Java实现文件的读写，复制

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * 测试文件的读取、写入、复制功能
 * @package :java05
 * @author shaobn
 * @Describe :测试文件的读取、写入、复制功能
 * @Time: 2015-9-5 下午10:50:18
 */
public class TestCopyText {
    public static void main(String[] args) throws Exception{
        //读取文件并打印
        System.out.println(readText(new FileInputStream("D:\hello.txt")));
        //写入内容至文件
        writeText(new FileOutputStream("D:\hellocopy.txt"), "您好，读写文件一般都用字符流，这种方式不推荐！");
        //复制文件，上面写入文件内容不变
        writeText(new FileOutputStream("D:\hellocopy.txt",true),readText(new FileInputStream("D:\hello.txt")));
    }
    //用FileInputStream读取文件
    public static String readText(InputStream is){
        BufferedInputStream bis = null;
        String str = null;
        try {
            bis = new BufferedInputStream(is);
            int len = 0;
            byte[] by = new byte[1024];
            while((len=bis.read(by))!=-1){
                str = new String(by,0,len);
            }
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }finally{
            try {
                if(bis!=null){
                    bis.close();
                    return str;
                }
            } catch (Exception e2) {
                // TODO: handle exception
                e2.printStackTrace();
            }
        }
        return str;
    }
    //用FileOutputStream写入文件
    public static void writeText(OutputStream os,String str){
        BufferedOutputStream bos = null;
        try {
            bos = new BufferedOutputStream(os);
            bos.write(str.getBytes());
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }finally{
            try{
            if(bos!=null){
                bos.close();
            }
            }catch (Exception e) {
                // TODO: handle exception
                e.printStackTrace();
            }
            
        }
        
    }
}

声明一下：一般读写文本文件均为字符流，笔者用字节流来写，推荐大家使用字符流读写文本文件。