javaÎļþºÍÎļþ¼ÐµÄ²Ù×÷

import java.io.BufferedReader;  
import java.io.File;  
import java.io.FileInputStream;  
import java.io.FileOutputStream;  
import java.io.FileWriter;  
import java.io.IOException;  
import java.io.InputStream;  
import java.io.InputStreamReader;  
import java.io.PrintWriter;  
import java.util.StringTokenizer;  
public class FileOperate {  
    private String message;  
    public FileOperate() {  
    }  
    /** 
     * ¶ÁÈ¡Îı¾ÎļþÄÚÈÝ 
     * @param filePathAndName ´øÓÐÍêÕû¾ø¶Ô·¾¶µÄÎļþÃû 
     * @param encoding Îı¾Îļþ´ò¿ªµÄ±àÂ뷽ʽ 
     * @return ·µ»ØÎı¾ÎļþµÄÄÚÈÝ 
     */  
    public String readTxt(String filePathAndName,String encoding) throws IOException{  
     encoding = encoding.trim();  
     StringBuffer str = new StringBuffer("");  
     String st = "";  
     try{  
      FileInputStream fs = new FileInputStream(filePathAndName);  
      InputStreamReader isr;  
      if(encoding.equals("")){  
       isr = new InputStreamReader(fs);  
      }else{  
       isr = new InputStreamReader(fs,encoding);  
      }  
      BufferedReader br = new BufferedReader(isr);  
      try{