java中synchronized的范例
来源:互联网 发布:java 字符串乱码 编辑:程序博客网 时间:2024/05/21 06:18
java中Synchronized的范例:
(1)同步的关键:
同步的关键是多个线程对象竞争同一个共享资源即可。要想实现线程的同步,则多个线程必须去竞争一个唯一的共享的对象锁。
(二)描述:
创建10个线程,每个线程都打印从0到99这100个数字,我们希望线程之间不会出现交叉乱序打印,而是顺序地打印。
(1)方法一:
class MyThread implements java.lang.Runnable
{
private int threadId;
public MyThread(int id)
{
this.threadId = id;
}
@Override
public synchronized void run()
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + this.threadId + " : " + i);
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i)).start();
Thread.sleep(1);
}
}
}
分析:不可以顺序打印;
(2)方法二:
class MyThread implements java.lang.Runnable
{
private int threadId;
private Object lock;
public MyThread(int id, Object obj)
{
this.threadId = id;
this.lock = obj;
}
@Override
public void run()
{
synchronized(lock)
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + this.threadId + " : " + i);
}
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
Object obj = new Object();
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i, obj)).start();
Thread.sleep(1);
}
}
}
分析:通过外部创建共享资源,然后传递到线程中来实现。
(3)方法三:
class MyThread implements java.lang.Runnable
{
private int threadId;
private static Object lock = new Object();
public MyThread(int id)
{
this.threadId = id;
}
@Override
public void run()
{
synchronized(lock)
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + this.threadId + " : " + i);
}
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i)).start();
Thread.sleep(1);
}
}
}
分析:
利用类成员变量被所有类的实例所共享这一特性,因此可以将lock用静态成员对象来实现。
(四)方法四:
class MyThread implements java.lang.Runnable
{
private int threadId;
public MyThread(int id)
{
this.threadId = id;
}
@Override
public void run()
{
taskHandler(this.threadId);
}
private static synchronized void taskHandler(int threadId)
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + threadId + " : " + i);
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i)).start();
Thread.sleep(1);
}
}
}
分析:实例方法中加入sychronized关键字封锁的是this对象本身,而在静态方法中加入sychronized关键字封锁的就是类本身。静态方法是所有类实例对象所共享的,因此线程对象在访问此静态方法时是互斥访问的,从而可以实现线程的同步
(1)同步的关键:
同步的关键是多个线程对象竞争同一个共享资源即可。要想实现线程的同步,则多个线程必须去竞争一个唯一的共享的对象锁。
(二)描述:
创建10个线程,每个线程都打印从0到99这100个数字,我们希望线程之间不会出现交叉乱序打印,而是顺序地打印。
(1)方法一:
class MyThread implements java.lang.Runnable
{
private int threadId;
public MyThread(int id)
{
this.threadId = id;
}
@Override
public synchronized void run()
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + this.threadId + " : " + i);
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i)).start();
Thread.sleep(1);
}
}
}
分析:不可以顺序打印;
(2)方法二:
class MyThread implements java.lang.Runnable
{
private int threadId;
private Object lock;
public MyThread(int id, Object obj)
{
this.threadId = id;
this.lock = obj;
}
@Override
public void run()
{
synchronized(lock)
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + this.threadId + " : " + i);
}
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
Object obj = new Object();
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i, obj)).start();
Thread.sleep(1);
}
}
}
分析:通过外部创建共享资源,然后传递到线程中来实现。
(3)方法三:
class MyThread implements java.lang.Runnable
{
private int threadId;
private static Object lock = new Object();
public MyThread(int id)
{
this.threadId = id;
}
@Override
public void run()
{
synchronized(lock)
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + this.threadId + " : " + i);
}
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i)).start();
Thread.sleep(1);
}
}
}
分析:
利用类成员变量被所有类的实例所共享这一特性,因此可以将lock用静态成员对象来实现。
(四)方法四:
class MyThread implements java.lang.Runnable
{
private int threadId;
public MyThread(int id)
{
this.threadId = id;
}
@Override
public void run()
{
taskHandler(this.threadId);
}
private static synchronized void taskHandler(int threadId)
{
for (int i = 0; i < 100; ++i)
{
System.out.println("Thread ID: " + threadId + " : " + i);
}
}
}
public class ThreadDemo
{
/**
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException
{
for (int i = 0; i < 10; ++i)
{
new Thread(new MyThread(i)).start();
Thread.sleep(1);
}
}
}
分析:实例方法中加入sychronized关键字封锁的是this对象本身,而在静态方法中加入sychronized关键字封锁的就是类本身。静态方法是所有类实例对象所共享的,因此线程对象在访问此静态方法时是互斥访问的,从而可以实现线程的同步
0 0
- java中synchronized的范例
- Synchronized(一)------java中Synchronized的用法
- java中synchronized的用法
- java中synchronized的用法
- java 中synchronized的详解
- Java中synchronized的用法
- java中synchronized的用法
- java中synchronized的用法
- Java中synchronized的用法
- Java中synchronized的用法
- Java中synchronized的用法
- java中synchronized的用法
- java中synchronized的用法
- Java中synchronized的使用
- Java 中synchronized的理解
- Java中synchronized的使用方法
- Java中Synchronized的用法
- Java中Synchronized的用法
- java中线程的创建
- C++顺序栈
- 矩阵行列式
- SWIFT 开发环境
- 判断MAC地址与预设值是否相同
- java中synchronized的范例
- java中多线程的同步与锁
- leetcode - Convert Sorted List to Binary Search Tree
- 最长递增子序列
- 最长递增子序列
- Objective-C:场景间传递数据
- nyist 119 士兵杀敌(三)
- JVM垃圾回收算法之新生代和老年代
- 关于标准ASCII码