Java修改excel内容

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
  
/**
 * 将aaa文件中的所有Study Subject ID开头的换成 “研究主题”，Protocol ID开头的换成“协议”。这个可以自己修改，根据需求不同灵活变化
 * @author sun
 *
 */
  
    public class WriteExcelPOI {
    
        public void writeExcelPOI() {
            try {

                String fileName = "D:\\aaa.xlsx";  //修改d盘的aaa.xlsx文件
                XSSFWorkbook xwb = new XSSFWorkbook(new FileInputStream(fileName));
                Map<String, String> fields = new HashMap<String, String>();
                fields = getFieldMap();  //获取要修改字段的集合
                String fillStr="";    //存储aaa文件里的数据
                String[] fillSplit=null; 
                XSSFSheet xSheet = xwb.getSheetAt(0);  //获取excel表的第一个sheet
                for (int i = 0; i <= xSheet.getLastRowNum(); i++) {  //遍历所有的行
                    if(xSheet.getRow(i)==null){ //这行为空执行下次循环
                        continue;
                    }
                    
                    for (int j = 0; j <=  xSheet.getRow(i).getPhysicalNumberOfCells(); j++) {  //遍历当前行的所有列
                        if(xSheet.getRow(i).getCell(j)==null){//为空执行下次循环
//                            System.out.println("qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq");
                            continue;
                        }
                        fillStr = (xSheet.getRow(i)).getCell(j).toString();//获取当前单元格的数据
                        fillSplit=fillStr.split("_");//切割，本人的数据是以"_"为分隔符的这个可以根据自己情况改变
//                        XSSFRow xRow = xSheet.createRow(i);
//                        XSSFCell xCell = xRow.createCell(j);
                        XSSFCell xCell=xSheet.getRow(i).getCell(j); //获取单元格对象，这块不能向上边那两句代码那么写，不能用createXXX，用的话会只把第一列的数据改掉
                        xCell.setCellValue(fields.get(fillSplit[0].trim())==null?fillStr:fields.get(fillSplit[0].trim()));//修改数据，看数据是否和字段集合中的数据匹配，不匹配使用元数据
//                        System.out.println(fields.get(fillSplit[0].trim()));
                    }
                }

                FileOutputStream out = new FileOutputStream(fileName);
                xwb.write(out);
                out.close();

            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        private String getValue(XSSFCell xCell) {
            if (xCell.getCellType() == XSSFCell.CELL_TYPE_BOOLEAN) {

                return String.valueOf(xCell.getBooleanCellValue());
            } else if (xCell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC) {

                return String.valueOf(xCell.getNumericCellValue());
            } else {

                return String.valueOf(xCell.getStringCellValue());
            }

        }

        private Map<String, String> getFieldMap(){
            Map<String, String> fields = new HashMap<String, String>();
            fields.put("Study Subject ID", "研究主题");
            fields.put("Protocol ID", "协议");
//            try{
//            String fileName = "D:\\yuan.xlsx";
//            XSSFWorkbook xwb = new XSSFWorkbook(new FileInputStream(fileName));
//        
//            XSSFSheet xSheet = xwb.getSheetAt(3);
//            for (int i = 0; i <= xSheet.getLastRowNum(); i++) {
//                fields.put(xSheet.getRow(i).getCell(0).toString(),xSheet.getRow(i).getCell(1).toString());
////                System.out.println("---"+xSheet.getRow(i).getCell(0)+"*---"+fields.get("A1"));
//                }
//            }
//            catch(Exception e){
//                e.printStackTrace();
//            }
            return fields;
        }
         public static void main(String[] args) {
            WriteExcelPOI a = new WriteExcelPOI();
            
            a.writeExcelPOI();
        }
    }