java FileWriter 追加文件及文件改名方式

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

public class FileWriterUtil {

     /**

      * 追加文件：使用FileWriter

      */

     public static void appendMethod(String fileName, String content) {

         try {

             //打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件

             FileWriter writer = new FileWriter(fileName, true );

             writer.write(content);

             writer.close();

         } catch (IOException e) {

             e.printStackTrace();

         }

     }

     /**

      * 修改文件名

      * @param oldFilePath

      * @param newFileName

      */

     public static void reNameLogFile(String oldFilePath,String newFileName){

         File f= new File(oldFilePath);

         String c=f.getParent();

//        File mm=new File(c + File.pathSeparator + newFileName + "_" + CommonUtil.getCurrTimeForString());

         File mm= new File(c + "/" + newFileName + "_" + CommonUtil.getBeforeDateStr());

         if (f.renameTo(mm)){

             System.out.println( "修改文件名成功!" );

         } else {

             System.out.println( "修改文件名失败" );

         }

     }

     public static void main(String[] args) {

         String fileName = "/Users/qin/Downloads/callLog.txt" ;

         String content = "new append!" ;

         FileWriterUtil.appendMethod(fileName, content);

         FileWriterUtil.appendMethod(fileName, "append end. \n" );

         FileWriterUtil.reNameLogFile( "/Users/qin/Downloads/callLog.txt" , "rayda" );

     }

}

import java.io.IOException;

import java.io.PrintWriter;

public class PrintWriteDemo

{

     public static void main(String[] args) throws IOException

     {

         PrintWriter out = new PrintWriter( "01.txt" );

         out.print( "the quick brown fox" );

         out.println( " jumps over the lazy dog." );

         out.write( "work is like a capricious lover whose " );

         out.write( "incessant demands are resented but who is missed terribly when she is not there\n" );

         out.close(); //如果不关闭文件，文件停留在buffer zone, 不会写进"01.txt"中

     }

}

import java.io.IOException;

import java.io.FileWriter;

public class FileWriterDemo

{

     public static void main(String[] args) throws IOException

     {

         FileWriter out = new FileWriter( "02.txt" );

         //constructor中添加true,即FileWriter out = new FileWriter("02.txt", true)就是往02.txt中追加文件了

         out.write( "work is like a capricious lover whose " );

         out.write( "incessant demands are resented but who is missed terribly when she is not there\n" );

         out.write( 98.7 + "\n" );

         out.close(); //很重要，一定记得关闭文件

     }

}