结合Poi实现可读取Excel的文件选择对话框

第一步：ApachePoi的jar包导全，不全会出现异常。

第二步：写就完事了：此例为读取特定模板的excel，仅供参考，根据实际需求改写。

package 自建包;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.WindowConstants;
import javax.swing.filechooser.FileFilter;

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.xssf.usermodel.XSSFWorkbook;

 

public class FileChooserUtils2 implements ActionListener {

//初始面板

 private JFrame f = null;
 private JLabel label = null;
 private JTextArea textarea = null;
 private JFileChooser fileChooser = null;

 public FileChooserUtils2() {
  f = new JFrame("FileChooser Example");
  Container contentPane = f.getContentPane();
  textarea = new JTextArea();
  JScrollPane scrollPane = new JScrollPane(textarea);
  scrollPane.setPreferredSize(new Dimension(350, 300));

  JPanel panel = new JPanel();
  JButton b1 = new JButton("新建文件");
  b1.addActionListener(this);
  JButton b2 = new JButton("存储文件");
  b2.addActionListener(this);
  panel.add(b1);
  panel.add(b2);

  label = new JLabel(" ", JLabel.CENTER);

  fileChooser = new JFileChooser("C:\\Users\\xjung\\Desktop"); //默认是我的桌面，修改一下。

  contentPane.add(label, BorderLayout.NORTH);
  contentPane.add(scrollPane, BorderLayout.CENTER);
  contentPane.add(panel, BorderLayout.SOUTH);

  f.pack();
  f.setVisible(true);
  f.setDefaultCloseOperation(WindowConstants.HIDE_ON_CLOSE);//按x不会退出程序
 }

 

 public static void main(String[] args) {
  new FileChooserUtils2();
 }

 

 public void actionPerformed(ActionEvent e) {
  File file = null;
  int result;

  if (e.getActionCommand().equals("新建文件")) {
   fileChooser.setApproveButtonText("确定");
   fileChooser.setDialogTitle("打开文件");
   fileChooser.addChoosableFileFilter(new JAVAFileFilter("xls", "xlsx"));   //加载过滤器
   fileChooser.addChoosableFileFilter(new JAVAFileFilter("java"));
   result = fileChooser.showOpenDialog(f);
   textarea.setText("");
   if (result == JFileChooser.APPROVE_OPTION) {
    file = fileChooser.getSelectedFile();
    label.setText("您选择打开的文件名称为：" + file.getName());
   } else if (result == JFileChooser.CANCEL_OPTION) {
    label.setText("您没有选择任何文件");
   }
   String extension="";
   int index = file.toString().lastIndexOf('.');
   if (index > 0 && index < file.toString().length() - 1) {
    extension = file.toString().substring(index + 1).toLowerCase();
   }
   if("xls".equals(extension)||"xlsx".equals(extension)) {
    readExcel(file.toString());
   }else {
    readNoExcel(file.toString());
   }

  }
  if (e.getActionCommand().equals("存储文件")) {
   result = fileChooser.showSaveDialog(f);
   file = null;

   if (result == JFileChooser.APPROVE_OPTION) {
    file = fileChooser.getSelectedFile();
    label.setText("您选择存储的文件名称为：" + file.getName());
   } else if (result == JFileChooser.CANCEL_OPTION) {
    label.setText("您没有选择任何文件");
   }

   FileOutputStream fileOutStream = null;

   if (file != null) {
    try {
     fileOutStream = new FileOutputStream(file);
    } catch (FileNotFoundException e2) {
     label.setText("File Not Found");
     return;
    }

    String content = textarea.getText();

    try {
     fileOutStream.write(content.getBytes());
    } catch (IOException e2) {
     label.setText("写入文件错误");
    } finally {
     try {
      if (fileOutStream != null)
       fileOutStream.close();
     } catch (IOException e3) {

     }

    }
   }
  }

 }
 

//读取非excel的文本方法
 private void readNoExcel(String file) {
  FileInputStream fileInStream = null;
  InputStreamReader isr = null;
  BufferedReader reader = null;
  if (file != null) {
   try {
    fileInStream = new FileInputStream(file);
    isr = new InputStreamReader(fileInStream, "UTF-8");
    reader = new BufferedReader(isr);
   } catch (FileNotFoundException e2) {
    label.setText("File Not Found");
    return;
   } catch (UnsupportedEncodingException e3) {
    label.setText("File Not Found");
    return;
   }

   String readStr;

   try {
    while ((readStr = reader.readLine()) != null) {
     textarea.append(readStr + "\n");
    }
   } catch (IOException e2) {
    label.setText("写入文件错误");
   } finally {
    try {
     if (fileInStream != null)
      fileInStream.close();
    } catch (IOException e3) {

    }
   }

  }
 }

 

//读取excel的内容
  private void readExcel(String fileName) {
         Workbook workbook = null;
         Row row = null;
       //获取Excel文档
         workbook = getWorkbook(fileName);
       //获取Excel文档的第一个sheet页
         Sheet sheet = workbook.getSheetAt(0);
       //获取文档中已保存数据的行数
         int rowNum = sheet.getPhysicalNumberOfRows();
       //获取第三行
         row = sheet.getRow(2);                                 //实现的是读取特定模板的excel，根据需求修改。
         int colnum=5;
         for (int i = 2; i < rowNum; i++) {
             row = sheet.getRow(i);
             if (null != row)
             {
              //获取当前行已保存数据的最大列数
              colnum = row.getPhysicalNumberOfCells();
                 for (int j = 0; j < colnum; j++) {
                     Cell cell =  row.getCell(j);
                     textarea.append(getValueFromCell(cell)+" ");
                     if(j==colnum-1) {
                      textarea.append("\n");
                     }
                 }
             }
         }
     }

 

     private static Workbook getWorkbook(String fileName) {//根据后缀获取Excel表格
         Workbook workbook = null;
         String suffix = fileName.substring(fileName.lastIndexOf(".") + 1);
         InputStream in = null;
         try {
             in = new FileInputStream(fileName);
             if ("xls".equals(suffix))
             {
                 workbook = new HSSFWorkbook(in);
             }
             else if ("xlsx".equals(suffix))
             {
                 workbook = new XSSFWorkbook(in);
             }
         } catch (FileNotFoundException e) {
             e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }
         return workbook;
     }
    
     private static String getValueFromCell(Cell cell) {//获取单元格的值ֵ
         String value = null;
         if (null == cell)
         {
             return "";
         }
       //判断cell类型
         switch(cell.getCellType()){
         case NUMERIC:{
             value = ""+(int)cell.getNumericCellValue();
             break;
         }
        
         case STRING:{
             value = cell.getStringCellValue();
             break;
         }
         default:
             value = "";
         }
         return value;
     }
}

//文件过滤器

class JAVAFileFilter extends FileFilter {
 String ext;
 String ext2;

 public JAVAFileFilter(String ext) {
  this.ext = ext;
 }

 public JAVAFileFilter(String ext, String ext2) {
  this.ext = ext;
  this.ext2 = ext2;
 }

//返回true过滤出文件

 public boolean accept(File file) {
  if (file.isDirectory())
   return true;

  String fileName = file.getName();
  int index = fileName.lastIndexOf('.');
  if (index > 0 && index < fileName.length() - 1) {
   String extension = fileName.substring(index + 1).toLowerCase();
   if (extension.equals(ext) || extension.equals(ext2))
    return true;
  }
  return false;
 }

//描述

 public String getDescription() {
  if (ext.equals("java"))
   return "JAVA Source File (*.java)";
  if (ext.equals("xls") && ext2.equals("xlsx"))
   return "JAVA Source File (*.xls/.xlsx)";
  return "";
 }
}