ThreadLocal 线程局部变量

ThreadLocal线程局部变量

package com.chen.thread;

import java.text.SimpleDateFormat;
import java.util.Random;

/**
* Created by CHEN on 2016/9/28.
*/
public class ThreadLocalExample implements Runnable {
//建立一个SimpleDateFormat的本地线程变量
private static final ThreadLocal<SimpleDateFormat> formatter =
new ThreadLocal<SimpleDateFormat>() {
//初始化
@Override
protected SimpleDateFormat initialValue() {
return new SimpleDateFormat("yyyyMMdd HHmm");
}
};

public static void main(String[] args) throws InterruptedException {
ThreadLocalExample obj = new ThreadLocalExample();
for (int i = 0; i < 10; i++) {
Thread t = new Thread(obj, "" + i);
Thread.sleep(new Random().nextInt(1000));
t.start();
}
}

@Override
public void run() {
//输出构造时的变量值
System.out.println("Thread Name= " + Thread.currentThread().getName() + " default Formatter = " + formatter.get().toPattern());
try {
Thread.sleep(new Random().nextInt(1000));
} catch (InterruptedException e) {
e.printStackTrace();
}
//对当前线程造成影响
formatter.set(new SimpleDateFormat());
//影响之后的结果
System.out.println("Thread Name= " + Thread.currentThread().getName() + " formatter = " + formatter.get().toPattern());
}

}