Java 装饰模式

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());
}
}