JAVA Useful Program(1)

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#JAVA Useful Program

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本文介绍如何在Java中实现字符串与整数之间的转换、向文件追加内容、获取调用方法名、字符串转日期、日期类型转换、以及使用NIO进行高效文件复制。

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public static void main(String[] args){
    //字符串有整型的相互转换
         String str=String.valueOf(123);
         int i=Integer.parseInt(str);
         System.out.println(i);
         //向文件末尾添加内容
         BufferedWriter out = null;
         try{
        out = new BufferedWriter(new FileWriter("c://logs//log.out", true));
        out.write("aString");
         }catch(IOException ex){
        System.out.println(ex.getMessage());
         }finally{
        if(out!=null){
           try {
     out.close();
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
        }
         }
         //得到当前方法的名字
         String methodName = Thread.currentThread().getStackTrace()[1].getMethodName();
         System.out.println(methodName);

         //转字符串到日期
         SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );
         try {
   Date date = format.parse("01.01.2013");
   System.out.println(date);
  } catch (ParseException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

  //把 Java util.Date 转成 sql.Date
  java.util.Date utilDate = new java.util.Date();
  java.sql.Date sqlDate = new java.sql.Date(utilDate.getTime());
  System.out.println(sqlDate);

  //使用NIO进行快速的文件拷贝
  File f1=new File("c://logs//log.out");
  File f2=new File("c://logs//log1.out");
  FileChannel inChannel=null;
  FileChannel outChannel=null;
  try {
   inChannel = new FileInputStream(f1).getChannel();
      outChannel = new FileOutputStream(f2).getChannel();
   try{
    int maxCount = (64 * 1024 * 1024) - (32 * 1024);
    long size = inChannel.size();
    long position = 0;
    while ( position < size ){
     position += inChannel.transferTo( position, maxCount, outChannel );

    }
   }catch(FileNotFoundException ex){
    ex.printStackTrace();
   } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  } catch (FileNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }finally{
   if(inChannel!=null){
    try {
     inChannel.close();
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
   if(outChannel!=null){
    try {
     outChannel.close();
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
  }

     }

Output:

123
main
Tue Jan 01 00:00:00 CST 2013
2013-06-17