装饰类:

package the_mass.decorator;import java.io.*;public class LogOutputStream extends OutputStream {    private OutputStream os;    public LogOutputStream(OutputStream outputStream) {        this.os = outputStream;    }    @Override    public void write(int b) throws IOException {        this.os.write(b);    }    @Override    public void write(byte[] b) throws IOException {        System.out.println("开始了");        super.write(b);        System.out.println("结束了");    }}

 

充当进度条：

package the_mass.decorator;import java.io.IOException;import java.io.OutputStream;public class ProgressOutStream extends OutputStream {    private OutputStream os;    public ProgressOutStream(OutputStream outputStream) {        this.os=outputStream;    }    @Override    public void write(int b) throws IOException {        this.os.write(b);    }    @Override    public void write(byte[] b) throws IOException {        System.out.println(">>>>>>>>>>>>>");        super.write(b);    }}

测试：

package the_mass.decorator;import java.io.FileOutputStream;import java.io.IOException;public class Main {    public static void main(String[] args) throws IOException {        FileOutputStream outputStream =new FileOutputStream("e:/aaa");        LogOutputStream los = new LogOutputStream(outputStream);        ProgressOutStream pos = new ProgressOutStream(outputStream);        los.write("welcome".getBytes()); //使用指定的字符集将字符串编码为 byte 序列，并将结果存储到一个新的 byte 数组中。        pos.write("Hello wrold".getBytes());}}