[英]Unable to write again to xls File using Apache POI
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
public class WriteToExcel
{
public static int rowCount=0;
public static void main(String[] args) throws IOException
{
File xlsFile =new File("C:\\Users\\Atul.Patel_New\\Desktop\\IDFC_MerchantOnBoarding_DocDwnld\\Reports\\Test.xls");
FileInputStream lFin = null;
HSSFWorkbook lWorkBook = null;
HSSFSheet lWorkSheet = null;
FileOutputStream lFout = null;
//POIFSFileSystem lPOIfs = null;
HSSFRow lRow=null;
int columnCount=0;
if(xlsFile.exists())
{
System.out.println("In Exists");
lFout=new FileOutputStream(xlsFile,true);
lFin=new FileInputStream(xlsFile);
//lPOIfs = new POIFSFileSystem(lFin);
lWorkBook=new HSSFWorkbook(lFin);
lWorkSheet = lWorkBook.getSheet("Java Books");
System.out.println(lWorkSheet.toString());
System.out.println("lWorkSheet.getLastRowNum():"+lWorkSheet.getLastRowNum()+1);
lRow = lWorkSheet.createRow(lWorkSheet.getLastRowNum());
}
else
{
xlsFile.createNewFile();
lFout = new FileOutputStream(xlsFile,true);
lWorkBook = new HSSFWorkbook();
lWorkSheet = lWorkBook.createSheet("Java Books");
System.out.println("Else: lWorkSheet.getLastRowNum():"+lWorkSheet.getLastRowNum());
lRow = lWorkSheet.createRow(lWorkSheet.getLastRowNum());
//columnCount = 0;
}
Object[][] bookData =
{
{"Head First Java", "Kathy Serria", 79},
{"Effective Java", "Joshua Bloch", 36},
{"Clean Code", "Robert martin", 42},
{"Thinking in Java", "Bruce Eckel", 35},
};
for (Object[] aBook : bookData)
{
Row row = lWorkSheet.createRow(rowCount);
columnCount = 0;
for (Object field : aBook)
{
Cell cell = row.createCell(columnCount);
if (field instanceof String)
{
cell.setCellValue((String) field);
}
else if (field instanceof Integer)
{
cell.setCellValue((Integer) field);
}
++columnCount;
}
++rowCount;
}
System.out.println("rowCount: "+rowCount);
try
{
lFin=new FileInputStream(xlsFile);
lFout=new FileOutputStream(xlsFile,true);
lWorkBook.write(lFout);
lFout.flush();
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
lFout.close();
lFin.close();
}
System.out.println("Done");
}
}
第一次執行將數據成功寫入xls。 但是在第二次執行時,xls中會出現與第一次執行時寫入的相同數據。
我可以看到兩個原因,為什么您在第二次運行中寫入的數據相同。
首先,我認為這是因為Object[][] bookData
從未更改。 您將始終將以下數據寫入excel文件:
{"Head First Java", "Kathy Serria", 79},
{"Effective Java", "Joshua Bloch", 36},
{"Clean Code", "Robert martin", 42},
{"Thinking in Java", "Bruce Eckel", 35}
其次,您還要始終將rowCount
和columnCount
重置為0,並且每次運行時代碼都會覆蓋相同的行和列。
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