poi操作excel記錄

好久沒有更新博客了，最近系統需要導出在導出各種各樣的Excel，所以就記錄一下poi導出Excel的文檔吧！

POI 概念

• Workbook：excel的文檔對象，一個文檔可以包含多個Sheet表格
• Sheet：excel的Sheet表格對象
• Row：excel的行對象
• Cell：excel的格子單元對象
• Font：excel字體對象
• CellStyle：cell樣式對象

封裝POI，根據模板導出文件

1.這裏隨意舉個例子：

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.*;
import java.lang.reflect.Field;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.*;

/**
 * 封裝Excel導出方法，使用公共模板導出
 */
public class ExcelUtils {
    private Workbook workbook;      // Excel對象，在此使用workbook來適配XSSFWorkbook和HSSFWorkbook兩種模式

    /**
     * 空的構造方法
     */
    public ExcelUtils() {
        this.workbook = new XSSFWorkbook();
    }

    /**
     * 構造Excel2007及其以後的版本
     * @param xssfWorkbook
     */
    public ExcelUtils(XSSFWorkbook xssfWorkbook) {
        this.workbook = xssfWorkbook;
    }

    /**
     * 構造Excel2007以前的版本
     * @param hssfWorkbook
     */
    public ExcelUtils(HSSFWorkbook hssfWorkbook) {
        this.workbook = hssfWorkbook;
    }

    /**
     * 根據模板渲染生成Excel時，讀取模板Excel
     * 系統會根據後綴名稱匹配Excel的版本信息，如果後綴不對，或者文件不存在，在返回null
     * @param excelPath
     * @return
     */
    public static ExcelUtils getExcelUtil(String excelPath) {

        File f = new File(excelPath);
        if(!f.exists())
            return null;

        try(FileInputStream fis = new FileInputStream(f)) {
            if(".xls".equals(excelPath.substring(excelPath.lastIndexOf(".")))) {
                return new ExcelUtils(new HSSFWorkbook(fis));
            } else if(".xlsx".equals(excelPath.substring(excelPath.lastIndexOf(".")))) {
                return new ExcelUtils(new XSSFWorkbook(fis));
            } else {
                throw null;
            }
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 清空指定下表的sheet中的全部內容
     */
    public void clear() {
        Sheet sheet = workbook.getSheetAt(0);
        for(int i = sheet.getLastRowNum();i >= 0;i--) {
            sheet.removeRow(sheet.getRow(i));
        }
        for (int i = sheet.getNumMergedRegions()-1;i >= 0;i--) {
            sheet.removeMergedRegion(i);
        }
    }

    /**
     * 生成一個sheet，並將主模板信息拷貝
     */
    public void copy() {
        Sheet record = workbook.createSheet();
        Sheet sheet = workbook.getSheetAt(0);
        for (int i = 0;i <= sheet.getLastRowNum();i++) {
            Row souRow = sheet.getRow(i);
            Row newRow = record.createRow(i);
            for (int j = 0;j < souRow.getLastCellNum();j++) {
                Cell newCell = newRow.createCell(j);
                newCell.setCellValue(souRow.getCell(j).getStringCellValue());
                newCell.setCellStyle(souRow.getCell(j).getCellStyle());
            }
        }
        for(int i = 0;i < sheet.getNumMergedRegions();i++) {
            CellRangeAddress souRange = sheet.getMergedRegion(i);
            CellRangeAddress newRange = new CellRangeAddress(souRange.getFirstRow(), souRange.getLastRow(), souRange.getFirstColumn(), souRange.getLastColumn());
            record.addMergedRegion(newRange);
        }
    }

    /**
     * 將拷貝模板追加到主模板尾部，重新填充
     */
    public void paste() {
        Sheet record = workbook.getSheetAt(workbook.getNumberOfSheets() - 1);
        Sheet sheet = workbook.getSheetAt(0);
        int lastNum = sheet.getLastRowNum() + 1;
        for (int i = 0;i <= record.getLastRowNum();i++) {
            Row souRow = record.getRow(i);
            Row newRow = sheet.createRow(lastNum + i);
            for (int j = 0;j < souRow.getLastCellNum();j++) {
                Cell cell = newRow.createCell(j);
                cell.setCellValue(souRow.getCell(j).getStringCellValue());
                cell.setCellStyle(souRow.getCell(j).getCellStyle());
            }
        }

        for(int i = 0;i < record.getNumMergedRegions();i++) {
            CellRangeAddress souRange = record.getMergedRegion(i);
            CellRangeAddress newRange = new CellRangeAddress(souRange.getFirstRow() + lastNum, souRange.getLastRow() + lastNum, souRange.getFirstColumn(), souRange.getLastColumn());
            sheet.addMergedRegion(newRange);
        }
    }

    /**
     * 刪除拷貝的模板
     */
    public void removeModel() {
        workbook.removeSheetAt(workbook.getNumberOfSheets() - 1);
    }


    /**
     * 填充頭部信息，使用實體類的方式
     * 這裏不是代表頭，而是使用#開頭的單元格標識
     * @param object
     */
    public void replaceHead(Object object) {
        for (Row row : workbook.getSheetAt(0)) {
            for (Cell cell : row) {
                if(cell.getCellType() == 1) {
                    String cellValue = cell.getStringCellValue().trim();
                    if(cellValue.startsWith("#")) {
                        String key = cellValue.substring(1);
                        Class<?> clazz = object.getClass();
                        Field f = null;
                        try {
                            f = clazz.getDeclaredField(key);
                        } catch (NoSuchFieldException e) {
                            e.printStackTrace();
                        }
                        boolean flag = f.isAccessible();
                        f.setAccessible(true);
                        try {
                            String value = "";
                            if(f.get(object) != null){
                                if("timestamp".equalsIgnoreCase(f.getType().getSimpleName())){
                                    value = new SimpleDateFormat("YYYY-MM-dd").format((Timestamp) f.get(object));
                                }else{
                                    value = String.valueOf(f.get(object));
                                }
                            }
                            cell.setCellValue(value);
                        } catch (IllegalAccessException e) {
                            e.printStackTrace();
                        }
                        f.setAccessible(flag);
                    }
                }
            }
        }
    }

    /**
     * 填充頭部信息，使用Map的方式
     * 這裏不是代表頭，而是使用#開頭的單元格標識
     * @param map
     */
    public void replaceHead(Map<String, Object> map) {
        for (Row row : workbook.getSheetAt(0)) {
            for (Cell cell : row) {
                if(cell.getCellType() == 1) {
                    String cellValue = cell.getStringCellValue().trim();
                    if(cellValue.startsWith("#")) {
                        String key = cellValue.substring(1);

                        String value = "";
                        if(map.get(key) != null) {
                            if(map.get(key) instanceof Timestamp){
                                value = new SimpleDateFormat("YYYY-MM-dd").format((Timestamp) map.get(key));
                            }else{
                                value = String.valueOf(map.get(key));
                            }
                        } else {
                            value = "";
                        }
                        cell.setCellValue(value);
                    }
                }
            }
        }
    }

    /**
     * 填充單list模板身部
     * @param list
     */
    public void replaceList(List<?> list) {
        Sheet sheet = workbook.getSheetAt(0);
        int rowIndex = 0;
        Map<String, Cell> map = new HashMap<>();
        for (Row row : sheet) {
            for (Cell cell : row) {
                if(cell.getCellType() == 1) {
                    String cellValue = cell.getStringCellValue().trim();
                    if(cellValue.startsWith("list.")) {
                        rowIndex = row.getRowNum();
                        String key = cellValue.substring(5);
                        map.put(key, cell);
                    }
                }
            }
        }
        if(list.size() > 1) {
            int lastRowNo = sheet.getLastRowNum();
            sheet.shiftRows(rowIndex + 1, lastRowNo, list.size() - 1);
            for(int i = rowIndex + 1;i < list.size() + rowIndex;i++) {
                Row souRow = sheet.getRow(rowIndex);
                Row newRow = sheet.createRow(i);
                for (int j = 0;j < souRow.getLastCellNum();j++) {
                    Cell cell = newRow.createCell(j);
                    cell.setCellValue(souRow.getCell(j).getStringCellValue());
                    cell.setCellStyle(souRow.getCell(j).getCellStyle());
                }
            }
        }
        setListCell(list, rowIndex, map);
    }


    /**
     * 填充list數據到excel
     * @param list
     * @param start
     * @param map
     */
    private void setListCell(List<?> list, int start, Map<String, Cell> map) {
        Sheet sheet = workbook.getSheetAt(0);
        for (int i = 0; i < list.size(); i++) {
            // Row row = sheet.createRow(start++);
            Row row = sheet.getRow(start++);
            Object o = list.get(i);
            for (String s : map.keySet()) {
                Cell cell = map.get(s);
                Cell c = row.getCell(cell.getColumnIndex());
                setCell(c, o, s, cell);
            }
        }
    }

    /**
     * 設置單元格
     * @param c
     * @param object
     * @param fieldName
     * @param cell
     */
    private void setCell(Cell c, Object object, String fieldName, Cell cell) {
        Class<?> clazz = object.getClass();
        Field f = null;
        try {
            f = clazz.getDeclaredField(fieldName);
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        }
        boolean flag = f.isAccessible();
        f.setAccessible(true);
        try {
            c.setCellValue(String.valueOf(f.get(object)));
            if(String.valueOf(f.get(object))=="null"){
                c.setCellValue("");
            }

        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        f.setAccessible(flag);
    }


    /**
     * 以流的方式輸出Excel
     * @param out
     */
    public void writeStream(OutputStream out) {
        try {
            workbook.write(out);
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}