IO字符流五种方式复制文件

package com.qyh.io;

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

/*
 * 字符流复制文本文件
 * 
 * 
 */

public class CopyTextDemo {
    public static void main(String[] args) throws IOException {
        method1("a.txt", "b.txt");
        method2("a.txt", "c.txt");
        method3("a.txt", "d.txt");
        method4("a.txt", "e.txt");
        method5("a.txt", "f.txt");
    }
    
    //高效字符流一次读取一行
    private static void method5(String srcString, String destString) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader(srcString));
        BufferedWriter bw = new BufferedWriter(new FileWriter(destString));
        
        String line = null;
        while((line=br.readLine())!=null) {
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        bw.close();
        br.close();
        
    }

    // 高效字符流一次读取一个字符数组
    private static void method4(String srcString, String destString) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader(srcString));
        BufferedWriter bw = new BufferedWriter(new FileWriter(destString));

        char[] ch = new char[1024];
        int len = 0;
        while ((len = br.read(ch)) != -1) {
            bw.write(ch, 0, len);
            bw.flush();
        }
        bw.close();
        br.close();

    }

    // 高效字符流一次读一个字符
    private static void method3(String srcString, String destString) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader(srcString));
        BufferedWriter bw = new BufferedWriter(new FileWriter(destString));

        int ch = 0;
        while ((ch = br.read()) != -1) {
            bw.write(ch);
        }
        bw.close();
        br.close();

    }

    // 一次读取一个字符数组
    private static void method2(String srcString, String destString) throws IOException {
        FileReader fr = new FileReader(srcString);
        FileWriter fw = new FileWriter(destString);

        char[] ch = new char[1024];
        int len = 0;
        while ((len = fr.read(ch)) != -1) {
            fw.write(ch, 0, len);
            fw.flush();
        }
        fw.close();
        fr.close();

    }

    // 一次读取一个字符
    private static void method1(String srcString, String destString) throws IOException {
        // 封装数据源
        FileReader fr = new FileReader(srcString);
        // 封装目的地
        FileWriter fw = new FileWriter(destString);
        // 读写数据
        int ch = 0;
        while ((ch = fr.read()) != -1) {
            fw.write(ch);
        }
        // 释放资源
        fw.close();
        fr.close();

    }

}