字符流

字符输入流Reader

 

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;public class Demo04 {public static void main(String[] args) throws IOException {method1();method2();method3();copy();}
FileReader类

 

//文本文件建议用字符流读取public static void method1() throws IOException{//创建字符输入流FileReader fr=new FileReader("E:\\java\\demo.txt");int len=0;while((len=fr.read())!=-1){System.out.println((char)len);}fr.close();}public static void method2() throws IOException{FileReader fr=new FileReader("E:\\java\\demo.txt");char[] ch=new char[2];int len=0;while((len=fr.read(ch))!=-1){System.out.println(new String(ch,0,len));//解码
        }fr.close();}
字符输出流Writer

 

FileWriter类
构造方法

 

//往文件里写public static void method3() throws IOException{FileWriter fw=new FileWriter("E:\\java\\demo.txt",true);fw.write(100);fw.flush();//刷一下char[] ch={'a','中'};fw.write(ch);fw.flush();fw.write("你好，小猪佩奇");fw.close();}
flush()和close()的区别？

 

复制文本文件//复制文本文件public static void copy() throws IOException{//明确数据源FileReader fr=new FileReader("E:\\java\\demo.txt");//明确目的文件FileWriter fw=new FileWriter("E:\\java\\c.txt");int len=0;char[] ch=new char[2];while((len=fr.read(ch))!=-1){fw.write(ch, 0, len);fw.flush();}fr.close();fw.close();}
}