阿里開源的這個庫，讓 Excel 導出不再複雜（簡簡單單的寫）

原創 看山 2021-10-12 15:03
{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"你好，我是看山。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"導出是中後臺常見的功能，Excel文件是常見的導出格式。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在Java棧中，常用的是","attrs":{}},{"type":"link","attrs":{"href":"https://sourceforge.net/projects/jexcelapi/","title":"","type":null},"content":[{"type":"text","text":"JXL（目前改名爲JExcel）","attrs":{}}]},{"type":"text","text":"和","attrs":{}},{"type":"link","attrs":{"href":"http://poi.apache.org/","title":"","type":null},"content":[{"type":"text","text":"Apache POI","attrs":{}}]},{"type":"text","text":"。其中jxl最後的更新時間是2012，除了老系統中能看到影子，幾乎見不到蹤跡了。目前基本上是POI一統天下。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"今天要說的EasyExcel阿里巴巴開源的Excel導出類庫，是對POI的封裝，實現了很多高級功能，並且留出擴展口，支持擴展定製化功能。打個比喻，POI相當於樂高積木，一個個的小積木可以自由組裝，只能動手能力強，就可以隨心所欲的組裝。EasyExcel更像是把這些小積木提前組裝好，想要搭建房子，就直接找組裝好的屋頂、圍牆就行。如果僅僅如此，那EasyExcel僅僅就是簡單的工具包，其更加吸引人的地方是對於內存的控制，它通過壓縮文件、分批讀取、拋棄不重要數據、文件緩存等多種方式，降低內存消耗。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"內容比較多，文內只會列出關鍵代碼，想要完整源碼，可以關注公號「看山的小屋」回覆“easyexcel”獲取。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"最簡單的寫表格","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"開始之前，先定義一下基礎類，這個類將貫穿全文，所有的功能都是在這個類的簡單變形。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"@Data\npublic class Item {\n @ExcelProperty(\"字符串標題\")\n private String string;\n @ExcelProperty(\"日期標題\")\n private Date date;\n @ExcelProperty(\"數字標題\")\n private Double doubleData;\n @ExcelIgnore\n private String ignore;\n}\n","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"根據頭對象和列表向一個工作表中寫一個表格","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這是最簡單的一種實現，只需要定義一個對象類，然後讀取數據列表即可。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"/**\n * 藉助{@link com.alibaba.excel.write.builder.ExcelWriterSheetBuilder}自動創建{@link com.alibaba.excel.ExcelWriter}寫入數據。\n *

\n * 提供列表和函數作爲數據源\n */\npublic static void writeAutoWriter() {\n final String fileName = defaultFileName(\"writeAutoWriter\");\n EasyExcelFactory.write(fileName)\n .head(Item.class)\n .sheet(\"模板\")\n .doWrite(WriteSample::sampleItems);\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"EasyExcel提供了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"EasyExcelFactory","attrs":{}}],"attrs":{}},{"type":"text","text":"類，API方法也是fluent方式，可以如絲般順滑的實現生成Excel文件。如果感覺","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"EasyExcelFactory","attrs":{}}],"attrs":{}},{"type":"text","text":"太長，還可以直接寫作","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"EasyExcel","attrs":{}}],"attrs":{}},{"type":"text","text":"，這是","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"EasyExcelFactory","attrs":{}}],"attrs":{}},{"type":"text","text":"的子類，類似於別名。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"不過，這種別名定義方式，在有些規範中屬於","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"smell 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* 手動創建{@link com.alibaba.excel.ExcelWriter}，指定sheet寫入數據。\n *

\n * 提供列表和函數作爲數據源\n */\npublic static void writeManualWither() {\n String fileName = defaultFileName(\"writeManualWriter\");\n ExcelWriter excelWriter = null;\n try {\n excelWriter = EasyExcelFactory.write(fileName)\n .head(Item.class)\n .build();\n final WriteSheet writeSheet1 = EasyExcelFactory.writerSheet(\"模板1\").build();\n excelWriter.write(WriteSample::sampleItems, writeSheet1);\n\n final WriteSheet writeSheet2 = EasyExcelFactory.writerSheet(\"模板2\").build();\n excelWriter.write(sampleItems(), writeSheet2);\n } finally {\n // 千萬別忘記finish 會幫忙關閉流\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"因爲是想多個工作表中寫數據，我們就不能直接使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"doWrite","attrs":{}}],"attrs":{}},{"type":"text","text":"方法了。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.ExcelWriter","attrs":{}}],"attrs":{}},{"type":"text","text":"類是Excel寫對象，用來創建Excel工作簿的。","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.write.metadata.WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"類是Sheet寫對象，用來創建Sheet工作表的。通過","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.ExcelWriter#write()","attrs":{}}],"attrs":{}},{"type":"text","text":"方法，指定寫入數據和寫入的目標工作表，就可以實現向多個工作表中寫數據的功能。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"此處需要注意，我們在創建","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriter","attrs":{}}],"attrs":{}},{"type":"text","text":"對象時，調用了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"head()","attrs":{}}],"attrs":{}},{"type":"text","text":"方法定義了表頭，這是整個Excel的定義，sheet會繼承這個定義。這樣，整個Excel文件中的所有工作表，表頭都是相同的。不要停，後面會給出不同工作表定義不同表頭的示例。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/8f/8f2c86fea7f678a4456af7727f7feeb6.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"按照定義指定導出列","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在後臺系統中，會有行列權限的控制。行權限，通過數據行實現，只導出有權限的行數據即可。列權限，可以通過只導出有權限的列，排除沒有權限的列（通常是分等級的敏感數據）。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"有時候需要定製化導出，導出所有列表格比較大，用戶根據需要指定需要導出的列。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"排除指定列","attrs":{}}]},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeExcludeColumn() {\n String fileName = defaultFileName(\"writeExcludeColumn\");\n Set excludeColumnFiledNames = new HashSet<>();\n excludeColumnFiledNames.add(\"date\");\n\n EasyExcelFactory.write(fileName)\n .head(Item.class)\n .excludeColumnFiledNames(excludeColumnFiledNames)\n .sheet(\"模板\")\n .doWrite(WriteSample::sampleItems);\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這個需求，需要藉助","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.write.builder.AbstractExcelWriterParameterBuilder#excludeColumnFiledNames","attrs":{}}],"attrs":{}},{"type":"text","text":"方法。這個方法是在","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriterBuilder","attrs":{}}],"attrs":{}},{"type":"text","text":"、","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriterSheetBuilder","attrs":{}}],"attrs":{}},{"type":"text","text":"、","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriterTableBuilder","attrs":{}}],"attrs":{}},{"type":"text","text":"的父類中定義，也就是說，可以是整個Excel工作簿都排除指定字段，也可以是某個sheet工作表排除指定字段，還可以是table表格排除指定字段。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"除了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"excludeColumnFiledNames","attrs":{}}],"attrs":{}},{"type":"text","text":"通過字段名排除字段，還可以使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"excludeColumnIndexes","attrs":{}}],"attrs":{}},{"type":"text","text":"指定字段下標排除列，如果需要控制下標，需要在字段上定義","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelProperty","attrs":{}}],"attrs":{}},{"type":"text","text":"指明index屬性，這樣也能夠更好的固定字段下標。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/4e/4e0cc378e198949d197769add6820e99.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"只導出指定列","attrs":{}}]},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeIncludeColumn() {\n String fileName = defaultFileName(\"writeIncludeColumn\");\n Set includeColumnFiledNames = new HashSet<>();\n includeColumnFiledNames.add(\"date\");\n EasyExcelFactory.write(fileName)\n .head(Item.class)\n .includeColumnFiledNames(includeColumnFiledNames)\n .sheet(\"模板\")\n .doWrite(WriteSample::sampleItems);\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這個需求，需要藉助","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.write.builder.AbstractExcelWriterParameterBuilder#includeColumnFiledNames","attrs":{}}],"attrs":{}},{"type":"text","text":"方法。與","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"excludeColumnFiledNames","attrs":{}}],"attrs":{}},{"type":"text","text":"是相似，都是可以分級定義，用起來也是一樣的，只不過功能相反而已。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"同樣的，也可以使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"includeColumnIndexes","attrs":{}}],"attrs":{}},{"type":"text","text":"方法，通過指定字段下標指定列。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/4f/4f66653e0bea78329f4d5993b5d1c232.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"表頭","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"表頭的定義是比較關鍵的，會直接影響Excel文件的質量。所以，EasyExcel提供了比較豐富的表頭定義方法。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"原始表頭","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這裏定義了一個新的基礎類：","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"EmptyItem","attrs":{}}],"attrs":{}},{"type":"text","text":"，與","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"Item","attrs":{}}],"attrs":{}},{"type":"text","text":"的區別是移除了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelProperty","attrs":{}}],"attrs":{}},{"type":"text","text":"的定義。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"@Data\npublic class EmptyItem {\n private String string;\n private Date date;\n private Double doubleData;\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在這種情況下，會直接使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"EmptyItem","attrs":{}}],"attrs":{}},{"type":"text","text":"對象的字段作爲表頭名稱。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeNoAnnotation() {\n final String fileName = defaultFileName(\"writeNoAnnotation\");\n EasyExcelFactory.write(fileName)\n .head(EmptyItem.class)\n .sheet(\"模板\")\n .doWrite(WriteSample::sampleItems);\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這裏可以看到，EasyExcel對於表頭對象、表體列表對象，沒有強制要求必須是相同的對象，只要字段一致，就能夠正常組裝數據。","attrs":{}}]}],"attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/fd/fd3de63f420592b02060c43a3911911f.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"自定義表頭","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"使用字段作爲表頭顯然不是我們想要的，EasyExcel提供了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelProperty","attrs":{}}],"attrs":{}},{"type":"text","text":"註解，可以定義表頭的名稱。這個註解還提供了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"index","attrs":{}}],"attrs":{}},{"type":"text","text":"、","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"order","attrs":{}}],"attrs":{}},{"type":"text","text":"兩個屬性，可以定義列的位置和順序。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"@Data\npublic class IndexItem {\n @ExcelProperty(value = \"字符串標題\", index = 1)\n private String string;\n @ExcelProperty(value = \"日期標題\", index = 3)\n private Date date;\n @ExcelProperty(value = \"數字標題\", index = 5)\n private Double doubleData;\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"使用起來也很簡單：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeWithIndex() {\n final String fileName = defaultFileName(\"writeWithIndex\");\n EasyExcelFactory.write(fileName)\n .head(IndexItem.class)\n .sheet(\"模板\")\n .doWrite(WriteSample::sampleItems);\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/d9/d9ebdc43639974914ff18dadef3f2a18.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這裏需要注意一下，在使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelProperty","attrs":{}}],"attrs":{}},{"type":"text","text":"註解時，index表示字段放置第幾列，order表示順序。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"根據index和order的不同語義，對兩者的控制不同。如果index相同，直接會拋出異常，因爲程序無法判斷這個列放那個字段。如果index值中間有空的數字，就會出現空列。如果order和index同時使用，index優先佔據位置，order做排序。index=-1的話，使用java默認排序，order值越小，列越靠前。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"codeinline","content":[{"type":"text","text":"ExcelProperty","attrs":{}}],"attrs":{}},{"type":"text","text":"的value屬性是字符串數組，相當於一個字段可以定義多個頭，這樣就可以實現多級表頭。同時，如果位置相鄰的列定義列明相同，還會合並列。比如：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"@Data\npublic class ComplexHeadItem {\n @ExcelProperty({\"大標題\", \"字符串標題\"})\n private String string;\n @ExcelProperty(\"日期標題\")\n private Date date;\n @ExcelProperty({\"大標題\", \"數字標題0\"})\n private Double doubleData;\n @ExcelProperty({\"數字標題\"})\n private Double doubleData1;\n @ExcelProperty({\"數字標題\"})\n private Double doubleData2 = 0.0;\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/5b/5b170b11eaa3f8d7ce8771c35752545c.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"動態表頭、表體","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"前面的例子中，表頭定義都是傳入一個對象，通過解析對象的屬性字段，抽取表頭定義。有的時候，我們沒有辦法提前定義表頭對象，或者說，表頭是根據條件、權限等因素動態變化的，這個時候，就可以使用EasyExcel提供的動態表頭功能了。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"/**\n * 動態表頭，傳入的是{@code List>}格式數據。\n *

\n * 可以實現多層表頭。\n */\nprivate static void writeDynamicHead() {\n String fileName = defaultFileName(\"writeDynamicHead\");\n EasyExcelFactory.write(fileName)\n .head(dynamicHead())\n .sheet()\n .doWrite(sampleItems());\n}\n\nprivate static List> dynamicHead() {\n List> heads = new ArrayList<>();\n final List head0 = new ArrayList<>(Arrays.asList(\"頭0\", \"字符串標題【動態】\"));\n heads.add(head0);\n final List head1 = new ArrayList<>(Arrays.asList(\"頭0\", \"日期標題【動態】\"));\n heads.add(head1);\n final List head2 = new ArrayList<>(Collections.singletonList(\"數字標題【動態】\"));\n heads.add(head2);\n return heads;\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.metadata.AbstractParameterBuilder#head(java.util.List>)","attrs":{}}],"attrs":{}},{"type":"text","text":"方法，傳入","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"List>","attrs":{}}],"attrs":{}},{"type":"text","text":"類型的數據即可。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/5e/5ed1e13df09a2fc9feac3f6ec17c0197.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"當然，這樣做還不是徹底的動態。我們可以使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.write.builder.ExcelWriterSheetBuilder#doWrite(java.util.Collection>)","attrs":{}}],"attrs":{}},{"type":"text","text":"實現動態表體。代碼如下：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeDynamicData() {\n String fileName = defaultFileName(\"writeDynamicData\");\n EasyExcelFactory.write(fileName)\n .head(dynamicHead())\n .sheet()\n .doWrite(dynamicData());\n}\n\nprivate static List> dynamicData() {\n List> list = new ArrayList<>();\n for (int i = 0; i < 10; i++) {\n List data = new ArrayList<>();\n data.add(\"字符串\" + i);\n data.add(new Date());\n data.add((i + 1) * 0.1);\n list.add(data);\n }\n return list;\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/6f/6f8b454a5977797c53aada91290b1fc7.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"表頭國際化","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"互聯網無國界，很多時候，我們需要實現國際化。這個時候，我們可以使用動態表頭功能，傳入不同的表頭定義，生成不同的Excel文件。有時候，我們還需要提前定義表體的格式，使用動態表體可以實現。有沒有更加簡單方法呢？必須有。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"先定義格式化表頭對象：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"@Data\npublic class FormatContentItem {\n @ExcelProperty(value = \"字符串標題\", converter = TitleFormatConverter.class)\n private String string;\n @DateTimeFormat(\"yyyy年MM月dd日HH時mm分ss秒\")\n @ExcelProperty(value = \"日期標題\")\n private Date date;\n @NumberFormat(\"0.000%\")\n @ExcelProperty(\"數字標題\")\n private Double doubleData;\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"再實現國際化：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"/**\n * 可以同時設置head參數：\n * {@link AbstractParameterBuilder#head(java.util.List)}\n * {@link AbstractParameterBuilder#head(java.lang.Class)}\n *

\n * 對於表頭設置，最終起作用的是{@link AbstractParameterBuilder#head(java.util.List)}，這樣的話，我們可以實現國際化的配置。\n */\nprivate static void writeDynamicMultiHead() {\n String fileName = defaultFileName(\"writeDynamicMultiHead\");\n EasyExcelFactory.write(fileName)\n .head(dynamicHead())\n .head(FormatContentItem.class)\n .sheet()\n .doWrite(sampleItems());\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/ee/ee0b14846feb6d78eddb7c7720dee848.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"多次寫入","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"一般來說，中後臺的數據量都不小，有時候需要一次導出幾十萬行數據，甚至更多，而這種操作並不是常態，如果內存配置比較大，那大多數時間內存都是閒置狀態。此時，就可以藉助EasyExcel的文件緩存能力，分批寫入數據。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"向同一個excel同一個sheet中多次寫入","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"首先是比較常見的場景，向一個sheet工作表中分批寫入數據。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeOneSheet() {\n String fileName = defaultFileName(\"writeOneSheet\");\n ExcelWriter excelWriter = null;\n try {\n excelWriter = EasyExcelFactory.write(fileName)\n .head(Item.class)\n .build();\n final WriteSheet writeSheet = EasyExcelFactory.writerSheet(\"模板\").build();\n for (int i = 0; i < 5; i++) {\n excelWriter.write(sampleItems(), writeSheet);\n }\n } finally {\n // 千萬別忘記finish 會幫忙關閉流\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"首先定義","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriter","attrs":{}}],"attrs":{}},{"type":"text","text":"可以操作整個Excel工作簿，然後定義","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriter","attrs":{}}],"attrs":{}},{"type":"text","text":"sheet工作表，接下來就是循環調用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.ExcelWriter.write(java.util.Collection>, com.alibaba.excel.write.metadata.WriteSheet)","attrs":{}}],"attrs":{}},{"type":"text","text":"方法，將數據寫入到指定的sheet工作表中。這裏需要注意的是，最後一定要調用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.ExcelWriter.finish","attrs":{}}],"attrs":{}},{"type":"text","text":"方法，表示停止寫入並關閉流。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/75/759cb99bac7dc8d7ed1b997bd5976210.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"向同一個excel不同sheet中多次寫入（表頭相同）","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"還有一種場景是按月導出全年的訂單數據，每個月一個sheet工作表，這種導出的方式，表頭都是相同的。根據上面的經驗，我們需要定義多個","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"工作表對象，然後向該對象中寫數據。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這裏還可能有一種情況，就是我們需要在多個","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"工作表對象之間切換寫入，爲了不會找錯對象，可以指定","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"sheetNo","attrs":{}}],"attrs":{}},{"type":"text","text":"。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"代碼如下：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeDiffSheetWithSameHead() {\n String fileName = defaultFileName(\"writeDiffSheetWithSameHead\");\n ExcelWriter excelWriter = null;\n try {\n excelWriter = EasyExcelFactory.write(fileName)\n .head(Item.class)\n .build();\n for (int i = 0; i < 5; i++) {\n final WriteSheet writeSheet = EasyExcelFactory.writerSheet(i, \"模板\" + i)\n .build();\n excelWriter.write(sampleItems(), writeSheet);\n }\n } finally {\n // 千萬別忘記finish 會幫忙關閉流\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/30/307c827618e07979b7eac7eddbeae0ca.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/3c/3cef53ea7774e84f5893b19a1ad8ab81.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"向同一個excel不同sheet中多次寫入（表頭不同）","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"還有一種場景，導出指定時間範圍的訂單信息，一個sheet工作表放具體的商品信息，另一個sheet工作表放訂單收貨地址信息。這種場景就需要不同的表頭，根據前面的講解，我們知道，只需要在定義","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"對象時指定不同的表頭對象即可。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"代碼如下：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeDiffSheetWithDiffHead() {\n String fileName = defaultFileName(\"writeDiffSheetWithDiffHead\");\n ExcelWriter excelWriter = null;\n try {\n excelWriter = EasyExcelFactory.write(fileName)\n .build();\n\n final WriteSheet writeSheet0 = EasyExcelFactory.writerSheet(0, \"模板1\")\n .head(Item.class)\n .build();\n excelWriter.write(sampleItems(), writeSheet0);\n\n final WriteSheet writeSheet1 = EasyExcelFactory.writerSheet(1, \"模板2\")\n .head(ComplexHeadItem.class)\n .build();\n excelWriter.write(sampleItems(), writeSheet1);\n } finally {\n // 千萬別忘記finish 會幫忙關閉流\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/91/917d64063f22ed597a5ba00202900754.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/89/897147abe41bb42e6ee33accb1347f2d.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"實現多表","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"EasyExcel對於Excel文件定義分成了三層，","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"numberedlist","attrs":{"start":1,"normalizeStart":1},"content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":1,"align":null,"origin":null},"content":[{"type":"text","text":"工作簿，也就是Excel文件","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","text":"工作表，對應是Excel文件中的Sheet","attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":3,"align":null,"origin":null},"content":[{"type":"text","text":"表格，對應是Sheet中的有表頭、表體的組合","attrs":{}}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這裏所說的功能就是在一個Sheet中創建多個表格。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"同一表單中創建表格","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"這個是開胃菜，演示一下怎麼單獨指定表格。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeTable() {\n String fileName = defaultFileName(\"writeTable\");\n final ExcelWriter excelWriter = EasyExcelFactory.write(fileName)\n .head(Item.class)\n .build();\n try {\n // 把sheet設置爲不需要頭 不然會輸出sheet的頭 這樣看起來第一個table 就有2個頭了\n WriteSheet writeSheet = EasyExcelFactory.writerSheet()\n .needHead(Boolean.FALSE)\n .build();\n\n // 這裏必須指定需要頭，table 會繼承sheet的配置，sheet配置了不需要，table 默認也是不需要\n WriteTable writeTable0 = EasyExcelFactory.writerTable(0)\n .needHead(Boolean.TRUE)\n .build();\n\n excelWriter.write(sampleItems(), writeSheet, writeTable0);\n } finally {\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以看到，除了前面提過的","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriter","attrs":{}}],"attrs":{}},{"type":"text","text":"和","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"，這裏還用到了","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteTable","attrs":{}}],"attrs":{}},{"type":"text","text":"，這個就是表格的寫對象。有了這個對象，我們只要多創建幾個，就能夠實現在一個Sheet工作表中，創建多個表格的功能。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/c0/c0865cc830c9043af1976e6011a939f5.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"與前面的例子完全沒有差別，條條大路通羅馬。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"同一表單中創建不同表格（相同表頭）","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"有了上面的鋪墊，我們直接上代碼：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeTables() {\n String fileName = defaultFileName(\"writeTables\");\n final ExcelWriter excelWriter = EasyExcelFactory.write(fileName)\n .build();\n try {\n // 把sheet設置爲不需要頭 不然會輸出sheet的頭 這樣看起來第一個table 就有2個頭了\n WriteSheet writeSheet = EasyExcelFactory.writerSheet()\n .head(Item.class)\n .needHead(Boolean.FALSE)\n .build();\n\n // 這裏必須指定需要頭，table 會繼承sheet的配置，sheet配置了不需要，table 默認也是不需要\n WriteTable writeTable0 = EasyExcelFactory.writerTable(0)\n .needHead(Boolean.TRUE)\n .build();\n\n WriteTable writeTable1 = EasyExcelFactory.writerTable(1)\n .needHead(Boolean.TRUE)\n .build();\n // 第一次寫入會創建頭\n excelWriter.write(sampleItems(), writeSheet, writeTable0);\n // 第二次寫如也會創建頭，然後在第一次的後面寫入數據\n excelWriter.write(sampleItems(), writeSheet, writeTable1);\n } finally {\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"因爲使用的是相同的表頭，我們可以直接在","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"中定義表頭對象，通過繼承的方式，實現兩個表格的表頭是相同的。這裏需要注意一下，","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteSheet","attrs":{}}],"attrs":{}},{"type":"text","text":"構建時，設置","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"needHead(Boolean.FALSE)","attrs":{}}],"attrs":{}},{"type":"text","text":"，如果不設置或者設置爲true，那第一個表格就會有兩個表頭。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/fb/fb0ec6caa90c9b0575658fb6eb51f0b8.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"同一表單中創建不同表格（不同表頭）","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"舉一反三，對於不同表頭，我們只需要爲","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"WriteTable","attrs":{}}],"attrs":{}},{"type":"text","text":"對象設置不同表頭即可：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeTablesWithDiffHead() {\n String fileName = defaultFileName(\"writeTablesWithDiffHead\");\n final ExcelWriter excelWriter = EasyExcelFactory.write(fileName)\n .build();\n try {\n WriteSheet writeSheet = EasyExcelFactory.writerSheet()\n .build();\n\n WriteTable writeTable0 = EasyExcelFactory.writerTable(0)\n .head(Item.class)\n .build();\n excelWriter.write(sampleItems(), writeSheet, writeTable0);\n\n WriteTable writeTable1 = EasyExcelFactory.writerTable(1)\n .head(ComplexHeadItem.class)\n .build();\n excelWriter.write(sampleItems(), writeSheet, writeTable1);\n } finally {\n if (excelWriter != null) {\n excelWriter.finish();\n }\n }\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"結果爲：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/cf/cf9de2bb33118cb352f1112dc4f3849b.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"寫入模板文件（非填充）","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"有時候，我們需要按照某種模板導出數據，這類模板文件屬於固定樣式，沒有動態數據。比如前面幾行是標題、權限聲明、責任聲明之類的，緊跟着就是列表數據。如果全靠手工拼寫數據比較繁瑣，EasyExcel提供了寫入模板文件的方式。先看代碼：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"codeblock","attrs":{"lang":"java"},"content":[{"type":"text","text":"private static void writeByTemplate() {\n String fileName = defaultFileName(\"writeByTemplate\");\n String templateFile = getPath() + File.separator + \"template_write_after_fill.xlsx\";\n EasyExcelFactory.write(fileName)\n .withTemplate(templateFile)\n .head(Item.class)\n .sheet()\n .doWrite(sampleItems());\n}\n","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"需要使用","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"com.alibaba.excel.write.builder.ExcelWriterBuilder#withTemplate(java.lang.String)","attrs":{}}],"attrs":{}},{"type":"text","text":"指定模板文件路徑。withTemplate方法有幾個重載實現：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"numberedlist","attrs":{"start":1,"normalizeStart":1},"content":[{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":1,"align":null,"origin":null},"content":[{"type":"text","text":"指定模板文件路徑","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriterBuilder#withTemplate(java.lang.String)","attrs":{}}],"attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":2,"align":null,"origin":null},"content":[{"type":"text","text":"指定模板文件對象","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriterBuilder#withTemplate(java.io.File)","attrs":{}}],"attrs":{}}]}]},{"type":"listitem","attrs":{"listStyle":null},"content":[{"type":"paragraph","attrs":{"indent":0,"number":3,"align":null,"origin":null},"content":[{"type":"text","text":"指定模板文件輸入流","attrs":{}},{"type":"codeinline","content":[{"type":"text","text":"ExcelWriterBuilder#withTemplate(java.io.InputStream)","attrs":{}}],"attrs":{}}]}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"指定模板文件和模板文件對象都是操作文件的，需要有文件信息。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"指定模板文件輸入流是隻要文件流，這個可操作性空間就比較大了。比如，模板文件是可變的，我們可以基於一個帶變量的模板文件，使用填充寫入的方式初始化模板文件，然後再用模板寫入的方式，寫入列表。（這個會在技巧篇中詳細說明）","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"代碼中的模板文件內容：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/bd/bd2c93b8e3fc7db35f6a9a719a3602e4.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"導出文件的內容：","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/35/352a9db70240bc5d321c0430986e6292.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"可以看出，這種方式寫入的列表是以追加的方式寫入，原有的模板內容不會修改，會從第一行空白行開始寫列表信息。","attrs":{}}]},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"文末總結","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"本文從實戰角度說了一下 EasyExcel 如果實現寫表格，接下來會講解一下如何更好看的寫。","attrs":{}}]},{"type":"horizontalrule","attrs":{}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"你好，我是看山。遊於碼界，戲享人生。如果文章對您有幫助，請點贊、收藏、關注。我還整理了一些精品學習資料，關注公衆號「看山的小屋」，回覆“資料”即可獲得。","attrs":{}}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https://static001.geekbang.org/infoq/9e/9e305acd1cca75053c144cb28adc6061.png","alt":null,"title":null,"style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":null,"fromPaste":true,"pastePass":true}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}

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原創 2024-04-24 23:51:10

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原創 2024-04-24 23:51:03

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原創 2024-04-24 23:39:16

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