Java多线程基础（一）

发布时间：2020-12-14 06:33:48 所属栏目：Java 来源：网络整理

导读：1.什么是进程、线程 2.创建线程的方式（三种） 1. 采用实现 Runnable、Callable 接口的方式创建多线程时，线程类只是实现了 Runnable 接口或 Callable 接口，还可以继承其他类。 2. 使用继承 Thread 类的方式创建多线程时，编写简单，如果需要访问当前线程，

1.什么是进程、线程

2.创建线程的方式（三种）

1. 采用实现 Runnable、Callable 接口的方式创建多线程时，线程类只是实现了 Runnable 接口或 Callable 接口，还可以继承其他类。
2. 使用继承 Thread 类的方式创建多线程时，编写简单，如果需要访问当前线程，则无需使用 Thread.currentThread() 方法，直接使用 this 即可获得当前线程。

3.线程的状态及特性

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args) {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    MyThread myThread=<span style="color: #0000ff;"&gt;new</span> MyThread("name"<span style="color: #000000;"&gt;);
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt;myThread.run();</span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt;主线程</span>
    myThread.start();<span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt;多线程</span>

}

}
class MyThread extends Thread{

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; MyThread() {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}
public MyThread(String name) {
super(name);
}

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #0000ff;"&gt;for</span>(<span style="color: #0000ff;"&gt;int</span> i=0;i<20;i++<span style="color: #000000;"&gt;) {
        System.out.println(Thread.currentThread().getName()</span>+"→"+<span style="color: #000000;"&gt;i);
    }
}

}

创建线程，输出1~100之间的偶数。要求使用线程实现，继承Thread类

public class ThreadDemo2 {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args) {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    OutputEven outputEven=<span style="color: #0000ff;"&gt;new</span><span style="color: #000000;"&gt; OutputEven();
    outputEven.start();
}

}
class OutputEven extends Thread{

@Override
</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    <span style="color: #0000ff;"&gt;for</span>(<span style="color: #0000ff;"&gt;int</span> i=1;i<=100;i++<span style="color: #000000;"&gt;) {
        </span><span style="color: #0000ff;"&gt;if</span>(i%2==0<span style="color: #000000;"&gt;) {
            System.out.println(Thread.currentThread().getName()</span>+"→"+<span style="color: #000000;"&gt;i);
        }
    }
}

}

?使用线程模拟四个工人搬砖场景，谁抢到托运机谁去搬砖

public class ThreadDemo3 {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args) {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    Worker worker1=<span style="color: #0000ff;"&gt;new</span> Worker("张三1","搬砖"<span style="color: #000000;"&gt;);
    Worker worker2</span>=<span style="color: #0000ff;"&gt;new</span> Worker("张三2","搬砖"<span style="color: #000000;"&gt;);
    Worker worker3</span>=<span style="color: #0000ff;"&gt;new</span> Worker("张三3","搬砖"<span style="color: #000000;"&gt;);
    Worker worker4</span>=<span style="color: #0000ff;"&gt;new</span> Worker("张三4","搬砖"<span style="color: #000000;"&gt;);
    worker1.start();
    worker2.start();
    worker3.start();
    worker4.start();

}

}
class Worker extends Thread{
String name;
String task;

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; Worker() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>
    <span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
}

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; Worker(String name,String task) {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
    </span><span style="color: #0000ff;"&gt;this</span>.name =<span style="color: #000000;"&gt; name;
    </span><span style="color: #0000ff;"&gt;this</span>.task =<span style="color: #000000;"&gt; task;
}

@Override
</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>

work();
}
public void work() {
System.out.println(name+"正在"+task);
}
}

三个窗口都可以卖100张票。

public class ThreadDemo4 {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args) {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    WinTicket winTicket1=<span style="color: #0000ff;"&gt;new</span> WinTicket("窗口1"<span style="color: #000000;"&gt;);
    WinTicket winTicket2</span>=<span style="color: #0000ff;"&gt;new</span> WinTicket("窗口2"<span style="color: #000000;"&gt;);
    WinTicket winTicket3</span>=<span style="color: #0000ff;"&gt;new</span> WinTicket("窗口3"<span style="color: #000000;"&gt;);
    winTicket1.start();
    winTicket2.start();
    winTicket3.start();

}

}
class WinTicket extends Thread{
private int ticket=100;

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; WinTicket() {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}
public WinTicket(String name) {
super(name);
}
@Override
public void run() {
// TODO Auto-generated method stub
while(true) {
if(ticket>0) {
String name=Thread.currentThread().getName();
System.out.println(name+"卖出"+ticket--);
}else {
break;
}
}
}

}

?4.多个线程共享资源

public class ThreadDemo5 {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args) {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt;创建共享资源对象</span>
    TicketRes ticketRes=<span style="color: #0000ff;"&gt;new</span><span style="color: #000000;"&gt; TicketRes();
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt;创建线程对象</span>
    Thread w1=<span style="color: #0000ff;"&gt;new</span> Thread(ticketRes,"窗口1"<span style="color: #000000;"&gt;);
    Thread w2</span>=<span style="color: #0000ff;"&gt;new</span> Thread(ticketRes,"窗口2"<span style="color: #000000;"&gt;);
    Thread w3</span>=<span style="color: #0000ff;"&gt;new</span> Thread(ticketRes,"窗口3"<span style="color: #000000;"&gt;);
    w1.start();
    w2.start();
    w3.start();
}

}
//共享资源类
class TicketRes implements Runnable{
private int ticket=100;

@Override
</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    <span style="color: #0000ff;"&gt;while</span>(<span style="color: #0000ff;"&gt;true</span><span style="color: #000000;"&gt;) {
        </span><span style="color: #0000ff;"&gt;if</span>(ticket>=1<span style="color: #000000;"&gt;) {
            System.out.println(Thread.currentThread().getName()</span>+"卖第"+ticket+"张票"<span style="color: #000000;"&gt;);
            ticket</span>--<span style="color: #000000;"&gt;;
        }</span><span style="color: #0000ff;"&gt;else</span><span style="color: #000000;"&gt; {
            </span><span style="color: #0000ff;"&gt;break</span><span style="color: #000000;"&gt;;
        }
    }
}

}
//出现一个问题：第一百张票会同时在三个窗口卖出。这个涉及到同步和异步的问题？该怎么解决呢？<a href="https://www.cnblogs.com/loober/p/10235234.html" target="_blank">Java多线程基础（二）揭晓答案

5.线程调度

优先级

调度方法

public class JoinDemo {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span> main(String[] args) <span style="color: #0000ff;"&gt;throws</span><span style="color: #000000;"&gt; InterruptedException {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    System.out.println("主线程在执行..."<span style="color: #000000;"&gt;);
    JoinThread joinThread1</span>=<span style="color: #0000ff;"&gt;new</span> JoinThread("线程1"<span style="color: #000000;"&gt;);
    JoinThread joinThread2</span>=<span style="color: #0000ff;"&gt;new</span> JoinThread("线程2"<span style="color: #000000;"&gt;);
    JoinThread joinThread3</span>=<span style="color: #0000ff;"&gt;new</span> JoinThread("线程3"<span style="color: #000000;"&gt;);
    System.out.println(</span>"启动子线程..."<span style="color: #000000;"&gt;);
    joinThread1.start();
    joinThread2.start();
    joinThread3.start();
    joinThread1.join();
    joinThread2.join();
    joinThread3.join();
    </span><span style="color: #0000ff;"&gt;for</span>(<span style="color: #0000ff;"&gt;int</span> i=0;i<10;i++<span style="color: #000000;"&gt;) {
        System.out.println(</span>"主线程正在执行..."<span style="color: #000000;"&gt;);
    }
    System.out.println(</span>"结束"<span style="color: #000000;"&gt;);
}

}
class JoinThread extends Thread{

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; JoinThread() {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; JoinThread(String name) {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;(name);
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}

@Override
</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    <span style="color: #0000ff;"&gt;for</span>(<span style="color: #0000ff;"&gt;int</span> i=0;i<10;i++<span style="color: #000000;"&gt;) {
        System.out.println(Thread.currentThread().getName()</span>+"→"+<span style="color: #000000;"&gt;i);
    }
}

}

public class SleepDemo {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args){
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    SleepThread sleepThread=<span style="color: #0000ff;"&gt;new</span><span style="color: #000000;"&gt; SleepThread();
    sleepThread.start();
}

}
class SleepThread extends Thread{

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; SleepThread() {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; SleepThread(String name) {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;(name);
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}

@Override
</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    <span style="color: #0000ff;"&gt;for</span>(<span style="color: #0000ff;"&gt;int</span> i=10;i>=0;i--<span style="color: #000000;"&gt;) {
        </span><span style="color: #0000ff;"&gt;try</span><span style="color: #000000;"&gt; {
            Thread.sleep(</span>1000<span style="color: #000000;"&gt;);
            System.out.println(i);
        } </span><span style="color: #0000ff;"&gt;catch</span><span style="color: #000000;"&gt; (InterruptedException e) {
            </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated catch block</span>

e.printStackTrace();
}
}
}

}

public class YieldDemo {

</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;static</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; main(String[] args) {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    YieldThread yieldThread1=<span style="color: #0000ff;"&gt;new</span> YieldThread("线程1"<span style="color: #000000;"&gt;);
    YieldThread yieldThread2</span>=<span style="color: #0000ff;"&gt;new</span> YieldThread("线程2"<span style="color: #000000;"&gt;);
    yieldThread1.start();
    yieldThread2.start();
}

}
class YieldThread extends Thread{

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; YieldThread() {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;();
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}

</span><span style="color: #0000ff;"&gt;public</span><span style="color: #000000;"&gt; YieldThread(String name) {
    </span><span style="color: #0000ff;"&gt;super</span><span style="color: #000000;"&gt;(name);
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated constructor stub</span>

}

@Override
</span><span style="color: #0000ff;"&gt;public</span> <span style="color: #0000ff;"&gt;void</span><span style="color: #000000;"&gt; run() {
    </span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt; TODO Auto-generated method stub</span>
    <span style="color: #0000ff;"&gt;for</span>(<span style="color: #0000ff;"&gt;int</span> i=0;i<20;i++<span style="color: #000000;"&gt;) {
        System.out.println(Thread.currentThread().getName()</span>+"→"+<span style="color: #000000;"&gt;i);
        Thread.yield();</span><span style="color: #008000;"&gt;//</span><span style="color: #008000;"&gt;避让，谦让，让出CPU，还有再去抢的资格</span>

}
}

}

（编辑：李大同）

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