ThreadLocal

最新推荐文章于 2024-10-20 08:30:00 发布

hxtxgfzs

最新推荐文章于 2024-10-20 08:30:00 发布

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分类专栏： coreJava 文章标签：线程

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三个线程共享一个SequenceNumber，通过ThreadLocal为每个线程提供单独的副本，产生独立的序列号。

package com.gfzs.Thread;

public class SequenceNumber {
	private static ThreadLocal<Integer> seqNum = new ThreadLocal<Integer>() {
		public Integer initialValue() {
			return 0;
		}
	};
	
	public int getNextNum() {
		
		seqNum.set(seqNum.get()+1);
		
		return seqNum.get();
	} 
	
	public static void main(String[] args) {
		SequenceNumber sn = new SequenceNumber();
		TestClient tc1 = new TestClient(sn);
		TestClient tc2 = new TestClient(sn);
		TestClient tc3 = new TestClient(sn);
		tc1.start();
		tc2.start();
		tc3.start();
	}
	private static class TestClient extends Thread{
		private SequenceNumber sn;
		public TestClient (SequenceNumber sn) {
			this.sn = sn;
		}
		public void run() {
			for (int i = 0; i < 3; ++i) {
				System.out.println("thread["+Thread.currentThread().getName()+"] sn["+sn.getNextNum()+"]");
			}
		}
	}
}

输出

thread[Thread-0] sn[1]
thread[Thread-1] sn[1]
thread[Thread-2] sn[1]
thread[Thread-1] sn[2]
thread[Thread-1] sn[3]
thread[Thread-0] sn[2]
thread[Thread-2] sn[2]
thread[Thread-0] sn[3]
thread[Thread-2] sn[3]

参考《精通Spring 4.x》11.2.3