002BIO中的基本使用

最新推荐文章于 2023-12-19 15:38:24 发布

原创最新推荐文章于 2023-12-19 15:38:24 发布 · 225 阅读

0 ·

CC 4.0 BY-SA版权

BIO 专栏收录该内容

3 篇文章

订阅专栏

本文深入探讨了Java中文件的读写操作，包括不同方式的文件复制和读取，以及对GB2312和GBK编码兼容ASCII的解析。通过具体代码示例，展示了如何使用FileInputStream、FileOutputStream、BufferedInputStream、BufferedOutputStream和自定义的MyBufferStream进行文件处理。

需注意gb2312和GBK都是兼容ascii编码的。也就是说gbk包含了ascii中的字符映射。
　
我觉得这个应该是1

package stream;


import java.io.*;

public class MyStream {
    public static void main(String[] args) throws Exception {
        writer001();
//        read001();
//        read002();
//            read003();
//            copy001();
        long sta = System.currentTimeMillis();

//        copy002();
        copy003();
        long end = System.currentTimeMillis();
        System.out.println(end-sta+"毫秒");

    }

    private static void copy003() throws Exception {
        MyBufferStream myBufferStream = new MyBufferStream(new FileInputStream("d:/清弄-叙世.mp3"));
        BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("d:/2.mp3"));
        int res = 0;
        while ((res=myBufferStream.myread())!=-1){
            out.write(res);
        }
        myBufferStream.close();
        out.close();

    }

    private static void copy002() throws Exception {
        BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream("d:/清弄-叙世.mp3"));
        BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("d:/1.mp3"));
        int res = 0;
        while ((res=inputStream.read())!=-1){
                out.write(res);
        }
        inputStream.close();
        out.close();

    }

    private static void copy001() throws Exception {
        FileInputStream in = new FileInputStream("d:/1.jpg");
        FileOutputStream out = new FileOutputStream("d:/jingse.jpg");
        byte[] arr = new byte[1234];
        int res = 0;
        while ((res = in.read(arr)) != -1) {
            out.write(arr);
        }
        in.close();
        out.close();
    }

    private static void read003() throws Exception {
        FileInputStream in = new FileInputStream("st.txt");
        byte[] arr = new byte[in.available()];
        in.read(arr);
        System.out.println(new String(arr));




    }

    private static void read002() throws Exception {
        FileInputStream in = new FileInputStream("st.txt");
        byte[] arr = new byte[1234];
        int res =0;

        while ((res = in.read(arr)) != -1) {
            System.out.println(new String(arr,0,res));
        }

    }

    private static void writer001() throws Exception {

        FileOutputStream out = new FileOutputStream("st.txt",true);
        out.write("alsdkjflksdjlffsldkfj".getBytes());
        out.close();

    }

    private static void read001() throws Exception {
        FileInputStream inputStream = new FileInputStream("st.txt");
        int res = 0;
        while ((res = inputStream.read()) != -1) {
            System.out.println((char)res);
        }
        inputStream.close();

    }
}

字节的缓冲区返回int

package stream;

import java.io.IOException;
import java.io.InputStream;

public class MyBufferStream {
    private InputStream inputStream;
    private byte[] arr = new byte[1234];
    int position = 0;
    int count = 0;
    public MyBufferStream(InputStream inputStream) {
        this.inputStream = inputStream;
    }

    public int myread() throws IOException {
        if (count == 0) {


           count =  inputStream.read(arr);
            if (count < 0) {
                return -1;
            }
            position = 0;
        }
        count--;
        byte b = arr[position];

        position++;
        return b&255;//-1相关的问题


    }

    public void close() throws IOException {
        inputStream.close();
    }


}