Runnable

如何编写一个线程类

package Chapter21_Concurrence;

public class Excersize1 implements Runnable{
    private static int count = 3;
    public Excersize1() {
        System.out.println("Start the thread");
    }
    @Override
    public void run() {
        while(count -- >0) {
            System.out.println("output"+count);
        }
    }
}

• 开启一个线程调用run方法

@Test
    public void testEx1() {
        Excersize1 ex1 = new Excersize1();

        Thread threadA = new Thread(ex1);
        threadA.start();    
    }

输出结果

Start the thread
output 2
output 1
output 0

• run方法未同步时开启两个线程调用同一个run方法

@Test
    public void testEx1NonSychronized() {
        Excersize1 ex1 = new Excersize1();

        Thread threadA = new Thread(ex1);
        Thread threadB = new Thread(ex1);
        threadA.start();
        threadB.start();
    }

输出结果

Start the thread
output 1
output 1
output 0

• 当在run方法上添加synchronized关键字时的输出结果

@Override
    public synchronized void run() {
        while(count -- >0) {
            System.out.println("output "+count);
        }
    }

输出结果

Start the thread
output 2
output 1
output 0

调用Thread.getName()获取线程的名称

    @Test
    public void testEx1ThreadName() {
        Excersize1 ex1 = new Excersize1();

        Thread threadA = new Thread(ex1);
        Thread threadB = new Thread(ex1);
        threadA.start();
        threadB.start();

        System.out.println("Name of Thread A : "+threadA.getName());
        System.out.println("Name of Thread B : "+threadB.getName());


    }

输出

Start the thread
Name of Thread A : Thread-0
Name of Thread B : Thread-1
output 2
output 1
output 0

• 调用Thread.getPriority()方法获取线程的优先级，当我们不设置线程的优先级时，默认使用的是优先级是5，最大优先级是10

@Test
    public void testEx1ThreadPriority() {
        Excersize1 ex1 = new Excersize1();

        Thread threadA = new Thread(ex1);
        Thread threadB = new Thread(ex1);
        threadA.start();
        threadB.start();
        System.out.println("Priority of Thread A : "+threadA.getPriority());
        System.out.println("Priority of Thread A : "+threadB.getPriority());
    }

输出结果

Start the thread
Priority of Thread A : 5
Priority of Thread A : 5
output 2
output 1
output 0