对文件file的操作

对于文件的知识了解的很少，工作中对于这部分用的还是比较多的，而且用的还是比较深。自己应该好好学习学习这方面的知识。 
/**
      * 读取数据
      */ 
     public static String ReadDate() { 
        String url = "e:/2.txt"; 
        String file=null;
        try { 
             FileReader read = new FileReader(new File(url)); 
             StringBuffer sb = new StringBuffer(); 
             char ch[] = new char[1024]; 
             int d = read.read(ch); 
             while(d!=-1){ 
                 String str = new String(ch,0,d); 
                sb.append(str); 
                d = read.read(ch); 
              } 
            System.out.print(sb.toString());
             file=sb.toString();
         } catch (FileNotFoundException e) { 
              e.printStackTrace(); 
         } catch (IOException e) { 
            e.printStackTrace(); 
         } 
         return file;
     } 
      
     /**
      * 写入数据
      */ 
     public static void WriteDate() { 
          
            try{ 
                File file = new File("D:/abc.txt"); 
                if (file.exists()) { 
                     
                    file.delete(); 
                } 
                 
                file.createNewFile(); 
                 
                BufferedWriter output = new BufferedWriter(new FileWriter(file));  
                 
                ArrayList ResolveList = new ArrayList(); 
                 
               
                      String name=Test.ReadDate();
                    ResolveList.add(name); 
                     
               
                 
                for (int i=0 ;i<ResolveList.size(); i++) { 
                    output.write(String.valueOf(ResolveList.get(i)) + "\n"); 
                } 
                output.close(); 
            } catch (Exception ex) { 
                System.out.println(ex); 
            } 
          
     }