project_01/Editor

import java.io.*;
public class Editor{
  private String content;           //文本文件的内容
  private String filepath;          //文本文件的路径
  private String  charsetName;      //文本文件的字符编码
  
  public Editor(String filepath,String charsetName){
    this.filepath=filepath;
    this.charsetName=charsetName;  
  }
  
  //把文件中的内容输入到content属性中    
  public void load(){
    try{
      InputStream in1=new FileInputStream(filepath);
      InputStreamReader in2= 
              new InputStreamReader(in1,charsetName);
    
      BufferedReader in3=new BufferedReader(in2);

      String data=null;
      content="";
      while((data=in3.readLine())!=null)
        content+=data+"\n";

      in3.close();
    }catch(IOException e){}
  }

  //把content属性的内容输出到文件中
  public void save(){ 
    try{
      OutputStream out1=new FileOutputStream(filepath);
      OutputStreamWriter out2
            =new OutputStreamWriter(out1,charsetName);
    
      PrintWriter out3=new PrintWriter(out2,true);
      out3.print(content);
      out3.close();
    }catch(IOException e){}
  }

  //获得文本内容 
  public String getContent(){  
    return content;
  }

  // 替换content属性中的特定字符串
  public void replace(String oldStr,String newStr){
    content=content.replace(oldStr,newStr);
  }  

  public static void main(String args[]){
    Editor editor=new Editor("D:\\mydir\\data.txt","UTF-8");
    editor.load();                    //加载data.txt文件
    editor.replace("Hello","Hi");  //替换特定字符串
    editor.save();                    //保存文件
  }
}