[移动开发]多线程 Java小结 【丑】——【上】

进程大致为一个可以独立运行的程序单位

线程的集合为进程，一般有main线程、gc线程

Thread? ? ? ? 创建线程【1】

package hk.Thread.deom1;

//继承Thread  ，重写run方法    ，调用start开启线程;
public class TextThread extends Thread{
    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println("run()——"+i);
        }
    }
    public static void main(String[] args) {

        //创建一个线程对象，调用start方法;开启线程；
        TextThread textThread = new TextThread();
        textThread.start();

        for (int i = 0; i < 5; i++) {
            System.out.println("main()——"+i);
        }
    }
}

?main（）for循环6次????????????????run（）for循环3次

??main（）for循环3次????????????????run（）for循环6次

?

?线程开启不一定立即执行；由cpu调度执行；=》同一程序每次运行次序有可能不同

package hk.Thread.deom1;
import org.apache.commons.io.FileUtils;
import java.io.File;
import java.io.IOException;
import java.net.URL;

public class TextDownloader extends Thread{
    private String url;
    private String name;
    public TextDownloader(String url ,String name){
        this.name=name;
        this.url=url;
    }
    @Override
    public void run() {
        Down down = new Down();
        down.down(this.url,this.name);
        System.out.println("下载结束    ："+name+"——:——"+url);
    }

    public static void main(String[] args) {
        TextDownloader textDownloader = new TextDownloader("https://staticls.tianqistatic.com/static/img/yujing.png","img1.jpg");
        TextDownloader textDownloader1 = new TextDownloader("https://content.pic.tianqistatic.com/contento/images/202204/05/e9aac8655667e3c4.jpg","img2.jpg");
        TextDownloader textDownloader2 = new TextDownloader("https://staticls.tianqistatic.com/static/img/yujing.png","img3.jpg");
        TextDownloader textDownloader0 = new TextDownloader("https://staticls.tianqistatic.com/static/img/logo_210.png","img0.jpg");

        textDownloader0.start();
        textDownloader.start();
        textDownloader1.start();
        textDownloader2.start();
    }
}
class Down{
    public void down(String url,String name){
        try {
            FileUtils.copyURLToFile(new URL(url),new File(name));
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("Down方法异常..."+url);
        }
    }
}

?多线程下载图片；没有ua伪装，有一个异常，其他三个成功多线程下载了

Runnable接口? ? ? ? 创建线程【2】? ? ? ? 【灵活方便? ? ? ? 推荐】

package hk.Thread.deom2;

public class Text1 implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 5; i++) {
            System.out.println("run——"+i);
        }
    }
    public static void main(String[] args) {
        Text1 text1 = new Text1();
        new Thread(text1).start();

        for (int i = 0; i < 3; i++) {
            System.out.println("main——"+i);
        }
    }
}

并发问题

多个线程同时操作同一资源，数据紊乱

package hk.Thread.deom3;

public class Text1 implements Runnable{
    private int ticketsum=5;

    @Override
    public void run() {
        while(true){
            if (ticketsum<=0){
                break;
            }
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName()+"ticket:    "+ticketsum--);
        }
    }

    public static void main(String[] args) {
        Text1 text1 = new Text1();

        new Thread(text1, "1").start();
        new Thread(text1, "2").start();
        new Thread(text1, "3").start();

    }
}

? Callable接口? ? ? ? 创建线程【3】? ? ? ? 可以定义返回值?

package hk.Thread.deom3;

import java.util.concurrent.*;

public class Text0 implements Callable {
    @Override
    public Boolean call() {
        for (int i = 0; i < 5; i++) {
            System.out.println(Thread.currentThread().getName()+"call——  "+i);
        }
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        Text0 text00 = new Text0();
        Text0 text01 = new Text0();
        //创建执行服务[线程个数]
        ExecutorService ser= Executors.newFixedThreadPool(2);
        //提交执行
        Future<Boolean> r0 =ser.submit(text00);
        Future<Boolean> r1 =ser.submit(text01);
        //获取结果
        boolean rs0=r0.get();
        boolean rs1=r1.get();
        System.out.println(rs0);
        System.out.println(rs1);
        //关闭服务
        ser.shutdown();
    }
}

?lambda 表达式 （参数）——> ?具体函数?

package hk.Thread.deom4;

public class Lambda {
    //2,静态内部类
    static class A2 implements A{
        @Override
        public void Fun() {
            System.out.println("A2——Fun()");
        }
    }
    public static void main(String[] args) {
        A a=new A1();
        a.Fun();

        a=new A2();
        a.Fun();

        //3,局部内部类
        class A3 implements A{
            @Override
            public void Fun() {
                System.out.println("A3——Fun()");
            }
        }
        a=new A3();
        a.Fun();

        //4,匿名内部类，没有类的名称，必须借助接口或者父类
        a=new A() {
            @Override
            public void Fun() {
                System.out.println("A4——Fun()");
            }
        };
        a.Fun();

        //5,lambda
        a=()-> {
            System.out.println("A5——Fun()");
        };
        a.Fun();
    }
}

//0.定义一个函数式接口
interface A{
    void Fun();
}

//1，实现类
class A1 implements A{
    @Override
    public void Fun() {
        System.out.println("A1——Fun()");
    }
}

package hk.Thread.deom4;

public class Text {
    public static void main(String[] args) {
        B b=(int...nums)->{
            int out=0;
            for (int num : nums) {
                out+=num;
            }
            System.out.println(out);
            return out;
        };
        int out=b.fun(1,2,3,4,5,6,7,8,9);
        System.out.println("out=    "+out);
    }
}
interface B{
    int fun(int...nums);
}

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