多线程-单例模式

单例模式

一、概念

饿汉模式、懒汉模式

二、示例

package com.study.current.thread.day02;

/**
 * 单例，多线程
 */
public class InnerSingleton {

	private static class Singletion{
		private static Singletion single = new Singletion();
	}
	
	public static Singletion getInstance(){
		return Singletion.single;
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}

}

package com.study.current.thread.day02;

import java.util.DuplicateFormatFlagsException;

public class DoubleCheckDemo {

	private static DoubleCheckDemo dc ;
	
	public static DoubleCheckDemo getDc(){
		if(dc == null){
			try {
				Thread.sleep(2000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			synchronized (DoubleCheckDemo.class) {
				if(dc == null){
					dc = new DoubleCheckDemo();
				}
			}
		}
		return dc ;
	}
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {

		Thread t1 = new Thread(new Runnable() {
			
			public void run() {
				System.out.println(DoubleCheckDemo.getDc().hashCode());
			}
		});
		
		Thread t2 = new Thread(new Runnable() {
			
			public void run() {
				System.out.println(DoubleCheckDemo.getDc().hashCode());
			}
		});
		
		t1.start();
		t2.start();
	}

}