Cirry's Blog

线程的命名与取得

构造方法：public Thread(Runnable target , String name);
设置名字：public final void setName(String name);
取得名字：public final String getName();

范例：

1
package cn.cccc.demo;
2
class MyThread implements Runnable{
3
    public void run (){
4
       System.out.println(Thread.currentThread().getName());
5
    }
6
}
7
public class ThreadDemo {
8
    public static void main(String[] args)  throws Exception {
9
       MyThread mt = new MyThread();
10
       new Thread(mt,"线程A").start();
11
       new Thread(mt).start();
12
       new Thread(mt,"线程B").start();
13
    }
14
}
15
//线程A
2 collapsed lines
16
//Thread-0
17
//线程B

线程的休眠休眠：public static void sleep(long millis ) throws InterruptedException; 休眠：public static void sleep(long millis, int nanos ) throws InterruptedException; 在进行休眠的时候可能会产生中断异常“InterruptedException”,中断异常属于Exception的子类必须处理。范例：

1
package cn.cccc.demo;
2
public class ThreadDemo {
3
    public static void main(String[] args)  throws Exception {
4
       new Thread(()->{
5
           for (int x= 0 ; x <10; x++){
6
               System.out.println(Thread.currentThread().getName()+"、x = " + x);
7
               try {
8
                  Thread.sleep(1000);   //暂缓执行
9
               } catch (Exception e) {
10
                  // TODO Auto-generated  catch block
11
                  e.printStackTrace();
12
               }
13
           }
14
       },"线程对象").start();
15
    }
1 collapsed line
16
}

线程中断在之前发现线程休眠提供有一个中断异常，实际上就证明线程的休眠是可以被打断的。在Thread类里面有提供这种中断执行的处理方法：判断线程是否被中断：public boolean isInterrupteed(); 中断线程执行：public void interrupt();

范例：

1
package cn.cccc.demo;
2
public class ThreadDemo {
3
    public static void main(String[] args)  throws Exception {
4
       Thread thread = new Thread(()->{
5
           System.out.println("我要睡觉了");
6
           try {
7
               Thread.sleep(3000);
8
               System.out.println("睡够了");
9
           } catch (Exception e) {
10
               // TODO Auto-generated catch  block
11
               System.out.println("敢打扰我睡觉，老子宰了你");
12
           }   //准备睡十秒
13

14
       });
15
       thread.start();
10 collapsed lines
16
       Thread.sleep(1000);
17
       if(!thread.isInterrupted()){
18
           System.out.println("打扰一下你睡觉");
19
           thread.interrupt();
20
       }
21
    }
22
}
23
//我要睡觉了
24
//打扰一下你睡觉
25
//敢打扰我睡觉，老子宰了你

所有执行的线程都是可以被中断的，中断线程必须进行异常的处理。

线程的强制执行：所为的线程的强制执行指的是当满足某些条件之后，某一个线程对象将可以一直独占资源，一直到该线程的程序执行结束。范例：观察一个没有强制执行的程序

1
package cn.cccc.demo;
2
public class ThreadDemo {
3
    public static void main(String[] args)  throws Exception {
4
       Thread thread = new Thread(()->{
5
           for (int x= 0; x < 100; x++) {
6
               System.out.println(Thread.currentThread().getName() + " 执行、 x = " + x);
7
           }
8
       },"玩耍的线程");
9
       thread.start();
10
       for(int x = 0; x < 100; x++){
11
           System.out.println("[霸道的main线程]number = " + x);
12
       }
13
    }
14
}

这个时候主线程和子线程都在交替执行，一直抢占资源。如果希望主程序独占执行，那么就可以利用：强制执行：public final void join() throws InterruptedException;

1
package cn.cccc.demo;
2
public class ThreadDemo {
3
    public static void main(String[] args)  throws Exception {
4
       Thread mainThread =  Thread.currentThread();   //获得主线程
5
       Thread thread = new Thread(()->{
6
           for (int x= 0; x < 100; x++) {
7
               if(x ==3 ){    // 如果执行到等于3 了，则霸道线程加入
8
                  try {
9
                      mainThread.join();
10
                  } catch (Exception e) {
11
                      // TODO Auto-generated  catch block
12
                      e.printStackTrace();
13
                  }
14
               }
15
               System.out.println(Thread.currentThread().getName() + " 执行、 x = " + x);
8 collapsed lines
16
           }
17
       },"玩耍的线程");
18
       thread.start();
19
       for(int x = 0; x < 100; x++){
20
           System.out.println("[霸道的main线程]number = " + x);
21
       }
22
    }
23
}

线程的礼让：线程的礼让指的是先将资源让出去让别的线程先执行。线程的礼让可以使用Thread中提供的方法：礼让：public static void yield(); 范例：礼让操作

1
package cn.cccc.demo;
2
public class ThreadDemo {
3
    public static void main(String[] args)  throws Exception {
4
       Thread mainThread =  Thread.currentThread();   //获得主线程
5
       Thread thread = new Thread(()->{
6

7
           for (int x= 0; x < 100; x++) {
8
               if(x %3 ==0 ){
9
                  Thread.yield();   //线程礼让
10
                  System.out.println("####线程的礼让操作####");
11
               }
12
               System.out.println(Thread.currentThread().getName() + " 执行、 x = " + x);
13
           }
14
       },"玩耍的线程");
15
       thread.start();
5 collapsed lines
16
       for(int x = 0; x < 100; x++){
17
           System.out.println("[霸道的main线程]number = " + x);
18
       }
19
    }
20
}

每次调用yeild()方法只会礼让一次。

线程的优先级：从理论上来讲，线程的优先级越高就越有可能先执行。在Thread类里面针对优先级操作有两个处理方法设置优先级:public final void setPriority(int newPriority) 获取优先级:public final int getPriority() 在进行优先级定义的时候都是通过int型的数字来完成的，而对于此数字的选择在Thread类里面就定义有三个常量：最高优先级：public static final int MAX_PRIORITY;(10) 中等优先级：public static final int NORM_PRIORITY;(5) 最低优先级：public static final int MIN_PRIORITY;(1)

1
package cn.cccc.demo;
2
public class ThreadDemo {
3
    public static void main(String[] args)  throws Exception {
4
       Runnable run = ()->{
5
           for(int x= 0; x < 5; x ++){
6
               try {
7
                  Thread.sleep(1000);
8
               } catch (Exception e) {
9
                  // TODO Auto-generated  catch block
10
                  e.printStackTrace();
11
               }
12
               System.out.println(Thread.currentThread().getName()+"执行");
13
           }
14
       };
15
       Thread threadA = new Thread(run , "线程对象A");
11 collapsed lines
16
       Thread threadB = new Thread(run , "线程对象B");
17
       Thread threadC = new Thread(run , "线程对象C");
18
       threadA.setPriority(1);
19
       threadB.setPriority(5);
20
       threadC.setPriority(10);
21
       threadA.start();
22
       threadB.start();
23
       threadC.start();
24

25
    }
26
}

优先级高的有可能限制性，而不是绝对先执行

线程常用的操作方法