synchronized一半同步一半异步（菜鸟玩线程）

一时失言乱红尘 2024-02-19 13:06 5阅读 0赞

## synchronized一半同步一半异步 ##

### 论证 ###

不在synchronized块中就是异步执行，在synchronized块中就是同步执行。

### 示例 ###

#### 自定义共享类 ####

package com.chapter02.thread4;
    
    public class Task {
        
        public void doLongTimeTask() {
        
            for (int i = 0; i < 100; i++) {
        
                System.out.println("NO SYNCHRONIZED THREAD NAME = " + Thread.currentThread().getName() + " i = " + (i + 1));
            }
           System.out.println("************************************************************************");
            synchronized (this) {
        
                for (int i = 0; i < 100; i++) {
        
                    System.out.println("SYNCHRONIZED THREAD NAME = " + Thread.currentThread().getName() + " i = " + (i + 1));
                }
            }
        }
    }

#### 自定义线程1 ####

package com.chapter02.thread4;
    
    
    public class MyThread1 extends Thread {
        
        private Task task;
    
        public MyThread1(Task task) {
        
            this.task = task;
        }
    
        @Override
        public void run() {
        
            super.run();
            task.doLongTimeTask();
        }
    }

#### 自定义线程2 ####

package com.chapter02.thread4;
    
    
    public class MyThread2 extends Thread {
        
        private Task task;
    
        public MyThread2(Task task) {
        
            this.task = task;
        }
    
        @Override
        public void run() {
        
            super.run();
            task.doLongTimeTask();
        }
    }

#### 启动类 ####

package com.chapter02.thread4;
    public class Run {
        
        public static void main(String[] args) {
        
            Task task = new Task();
            MyThread1 myThread1 = new MyThread1(task);
            myThread1.start();
    
            MyThread2 myThread2 = new MyThread2(task);
            myThread2.start();
        }
    }

#### 执行结果 ####

NO SYNCHRONIZED THREAD NAME = Thread-0 i = 1
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 2
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 3
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 4
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 5
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 6
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 7
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 8
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 9
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 10
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 11
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 12
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 13
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 14
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 15
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 16
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 17
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 18
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 19
    NO SYNCHRONIZED THREAD NAME = Thread-0 i = 20
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 1
    ************************************************************************************************
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 2
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 3
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 4
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 5
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 6
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 7
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 8
    SYNCHRONIZED THREAD NAME = Thread-0 i = 1
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 9
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 10
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 11
    SYNCHRONIZED THREAD NAME = Thread-0 i = 2
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 12
    SYNCHRONIZED THREAD NAME = Thread-0 i = 3
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 13
    SYNCHRONIZED THREAD NAME = Thread-0 i = 4
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 14
    SYNCHRONIZED THREAD NAME = Thread-0 i = 5
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 15
    SYNCHRONIZED THREAD NAME = Thread-0 i = 6
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 16
    SYNCHRONIZED THREAD NAME = Thread-0 i = 7
    SYNCHRONIZED THREAD NAME = Thread-0 i = 8
    SYNCHRONIZED THREAD NAME = Thread-0 i = 9
    SYNCHRONIZED THREAD NAME = Thread-0 i = 10
    SYNCHRONIZED THREAD NAME = Thread-0 i = 11
    SYNCHRONIZED THREAD NAME = Thread-0 i = 12
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 17
    SYNCHRONIZED THREAD NAME = Thread-0 i = 13
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 18
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 19
    NO SYNCHRONIZED THREAD NAME = Thread-1 i = 20
    ************************************************************************************************
    SYNCHRONIZED THREAD NAME = Thread-0 i = 14
    SYNCHRONIZED THREAD NAME = Thread-0 i = 15
    SYNCHRONIZED THREAD NAME = Thread-0 i = 16
    SYNCHRONIZED THREAD NAME = Thread-0 i = 17
    SYNCHRONIZED THREAD NAME = Thread-0 i = 18
    SYNCHRONIZED THREAD NAME = Thread-0 i = 19
    SYNCHRONIZED THREAD NAME = Thread-0 i = 20
    SYNCHRONIZED THREAD NAME = Thread-1 i = 1
    SYNCHRONIZED THREAD NAME = Thread-1 i = 2
    SYNCHRONIZED THREAD NAME = Thread-1 i = 3
    SYNCHRONIZED THREAD NAME = Thread-1 i = 4
    SYNCHRONIZED THREAD NAME = Thread-1 i = 5
    SYNCHRONIZED THREAD NAME = Thread-1 i = 6
    SYNCHRONIZED THREAD NAME = Thread-1 i = 7
    SYNCHRONIZED THREAD NAME = Thread-1 i = 8
    SYNCHRONIZED THREAD NAME = Thread-1 i = 9
    SYNCHRONIZED THREAD NAME = Thread-1 i = 10
    SYNCHRONIZED THREAD NAME = Thread-1 i = 11
    SYNCHRONIZED THREAD NAME = Thread-1 i = 12
    SYNCHRONIZED THREAD NAME = Thread-1 i = 13
    SYNCHRONIZED THREAD NAME = Thread-1 i = 14
    SYNCHRONIZED THREAD NAME = Thread-1 i = 15
    SYNCHRONIZED THREAD NAME = Thread-1 i = 16
    SYNCHRONIZED THREAD NAME = Thread-1 i = 17
    SYNCHRONIZED THREAD NAME = Thread-1 i = 18
    SYNCHRONIZED THREAD NAME = Thread-1 i = 19
    SYNCHRONIZED THREAD NAME = Thread-1 i = 20

### 结论 ###

如下所示，在进入synchronized代码块后则排队执行。