Java连载98-FileReader和FileWriter详解

Posted 2021-03-05 ruigege0000

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一、FileReader详解

1.java.io.Reader

java.io.InputStreamReader;转换流（字节输入流--->字符输入流）

java.io.FileReader?；文件字符输入流

2.java.io.Writer

java.io.OutputStreamWriter;转换流（字节输出流-->字节输出流）

java.io.FileWriter;文件字符输出流

 

package com.bjpowernode.java_learning;

import java.io.*;

public class D98_1_FileReaderAnalysis {

  public static void main(String[] args) {

    FileReader fr = null;

    FileWriter fw = null;

    try {

      //创建文件字符输入流

      fr = new FileReader("C:Userslenovo1WorkspacesMyEclipse CIJava_learningsrccomjpowernodejava_learning	emp1.txt");

      //开始读

      char[] chars = new char[512];//1kb

      int temp = 0;

      while((temp=fr.read(chars)) != -1) {

        //将char数组有效部分转换为字符串

        System.out.println(new String(chars,0,temp));

        //有一好处，读取文本类不会出现乱码，因为每次读取一个字符，而不是字节

      }

     

      //创建文件字符输出流

      fw = new FileWriter("C:Userslenovo1WorkspacesMyEclipse CIJava_learningsrccomjpowernodejava_learning	emp2.txt");

      //开始写

      fw.write("牛逼！");

      //将char数组的一部分写入

      char[] chars2 = {

        ‘我‘,‘是‘,‘中‘,‘国‘,‘人‘

      };

      fw.write(chars2);

      //刷新

      fw.flush();

      //关闭

      fw.close();

     

      //文件复制,只能复制纯文本文件

      FileReader fr2 = new FileReader("C:Userslenovo1WorkspacesMyEclipse CIJava_learningsrccomjpowernodejava_learning	emp1.txt");

      FileWriter fr3 = new FileWriter("C:Userslenovo1WorkspacesMyEclipse CIJava_learningsrccomjpowernodejava_learning	emp2.txt");

     

      char[] chars3 = new char[512];

      int temp2 = 0;

      while((temp2=fr2.read())!= -1) {

        fr3.write(chars3,0,temp2);

      }

      fr3.flush();

      fr3.close();   

    }catch(Exception e) {

      e.printStackTrace();

    }finally {  

    }

  }

}