java 讀取 寫入 csv 文件

csv  是以逗號進行分隔的文件，以換行符表示下一條記錄

讀文件：構建hashmap

Map<String, Integer> tempMap = new HashMap<String, Integer>();
String filePath = "******";
BufferedReader bufReader = new BufferedReader(new FileReader(filePath));
String lineStr = "";
int rowNumber = 0;
while ((lineStr = bufReader.readLine()) != null) {
tempMap.put(lineStr.split(",")[0],
Integer.parseInt(lineStr.split(",")[7]));
rowNumber++;
System.out.printf("xx:%d...\n ", rowNumber);
}
bufReader.close();

根據hashmap 匹配然後補上最後一列：

String filePath1 = "D:\\Users\\YUYI179\\Desktop\\work\\hz.csv";
BufferedReader bufReader1 = new BufferedReader(
new FileReader(filePath1));
int rowNumber1 = 0;
StringBuffer nContent = new StringBuffer();
while ((lineStr = bufReader1.readLine()) != null) {
int addValue = 0;
if (rowNumber1 != 0) {
try{
if(tempMap.get(lineStr.split(",")[0].substring(12))!=null)
addValue = tempMap.get(lineStr.split(",")[0].substring(12));
}catch(Exception ee){
@SuppressWarnings("unused")
int jj=0;
}
}
if (lineStr.endsWith(",")) {
nContent.append(lineStr).append("\"" + addValue + "\"");
} else {
nContent.append(lineStr).append(",\"" + addValue + "\"");
}
rowNumber1++;
nContent.append("\r\n");
}
bufReader1.close();

把流進制文件寫入文件。

FileOutputStream fileOs = new FileOutputStream(new File(filePath1),
false);////true表示如果文件已經存在，沒執行程序一次便往文件追加一次內容，false會每一次的執行結果會覆蓋文件上一次執行結果
fileOs.write(nContent.toString().getBytes());
fileOs.close();