字符流五种读写 字符流 BufferedWriter BufferedReader 带缓冲区的字符流

字符流五种读写

package test03;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import javax.annotation.processing.Filer;

public class CopyfileDemo {
    public static void main(String[] args) throws Exception {
        File src = new File("a.txt");
        File dest = new File("b.txt");
        copy1(src,dest);
        copy2(src,dest);
        copy3(src,dest);
        copy4(src,dest);
        copy5(src,dest);
    }
    //缓冲区字符流 特殊方法
    private static void copy5(File src, File dest) throws IOException {
        // TODO Auto-generated method stub
        BufferedReader br = new  BufferedReader(new FileReader(src));
        BufferedWriter bw = new BufferedWriter(new FileWriter(dest));
        
        String line = null;
        while((line  = br.readLine())!=null) {//一次读一行
            bw.write(line);
            bw.newLine();//换行
        }
        br.close();
        bw.close();
        
    }
    //带缓冲区字符流一次一个字符数组
    private static void copy4(File src, File dest) throws IOException {
        // TODO Auto-generated method stub
        BufferedReader br = new  BufferedReader(new FileReader(src));
        BufferedWriter bw = new BufferedWriter(new FileWriter(dest));
        int  len = 0;
        char[] chs = new  char[1024];
        while((len = br.read(chs))!=-1) {
            bw.write(chs, 0, len);
        }
        br.close();
        bw.close();
    }
    //缓冲区字符流 一次读一个字符
    private static void copy3(File src, File dest) throws Exception {
        // TODO Auto-generated method stub
        BufferedReader br = new  BufferedReader(new FileReader(src));
        BufferedWriter bw = new BufferedWriter(new FileWriter(dest));
        
        int  b = 0;
        while((b = br.read())!=-1) {
            bw.write(b);
        }
        br.close();
        bw.close();
        
        
    }
    //普通字符流 一次读写一个字符数组
    private static void copy2(File src, File dest) throws IOException {
        // TODO Auto-generated method stub
        FileReader fr  =new FileReader(src);
        FileWriter fw = new FileWriter(dest);
        
        int len = 0;
        char [] chs = new  char[1024];
        while((len = fr.read(chs))!=-1) {
            fw.write(chs,0,len);
        }
        fr.close();
        fw.close();
        
    }
    //普通字符流  一次读写一个字符
    private static void copy1(File src, File dest) throws IOException {
        // TODO Auto-generated method stub
        FileReader fr = new FileReader(src);
        FileWriter fw = new FileWriter(dest);
        
        int b = 0;
        while((b = fr.read())!=-1) {
            fw.write(b);
        }
        
        fr.close();
        fw.close();
        
        
    }
}

特殊方法

 BufferedReader

String

readLine()           读取一个文本行。

public class BufferedReaderDemo2 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("a.txt"));
        
        //一次读取一行
        /*String s = br.readLine();
        System.out.println(s);*/
        
        String line = null;
        while((line = br.readLine())!=null) {
            System.out.println(line);
        }    
        br.close();
    }
}

BufferedWriter

void	newLine()           写入一个行分隔符。

public static void main(String[] args) throws IOException {
        BufferedWriter bw = new  BufferedWriter(new FileWriter("a.txt"));
        bw.write(97);
        bw.write("helloword");
        bw.write("
");//换行符
        bw.newLine();//换行
        
        char[] ch = {'1','2','u','g','h','d'};
        bw.write(ch);
        bw.newLine();//换行
        
        bw.write("helloword");
        
        bw.close();
    }