IO流——文件内容的复制

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.*;

public class BisandBos_test {

    File file;
    FileInputStream fis;
    FileOutputStream fos;
    BufferedOutputStream bos;
    BufferedInputStream bis;

    //准备资源
    @Before
    public void creatFile() throws Exception {
       file = new File("resource//bis1.txt");

    }
    //写
    @Test
    public void write() throws  Exception {
        fos = new FileOutputStream(file,true);
        bos = new BufferedOutputStream(fos);
        bos.write("I love java".getBytes());
    }

    //读
    @Test
    public void read() throws  Exception {
        fis = new FileInputStream(file);
        bis = new BufferedInputStream(fis);
        byte[] bytes = new byte[1024];
        bis.read(bytes);
        System.out.println(new String(bytes));

    }

    //复制
    @Test
    public void copyFile() throws Exception {
        fis = new FileInputStream(file);
        bis = new BufferedInputStream(fis);

        fos = new FileOutputStream("resource//bis_copy.txt");
        bos = new BufferedOutputStream(fos);
        byte[] bytes1 = new byte[1024];
        int i = -1;
        while ((i = bis.read(bytes1)) != -1) {
            bos.write(bytes1);
        }


    }

    //关闭资源
    @After
    public void closeAll() throws  Exception {
        if (bos != null)  bos.close();
        if (bis != null)  bis.close();
        if (fos != null)  fos.close();
        if (fis != null)  fis.close();
    }



}