package com.coshaho.reflect;/*** ThreadLocal用法* @author coshaho**/
public class MyThreadLocal
{private static final ThreadLocal<Object> threadLocal = new ThreadLocal<Object>(){/*** ThreadLocal没有被当前线程赋值时或当前线程刚调用remove方法后调用get方法，返回此方法值*/@Overrideprotected Object initialValue(){System.out.println("调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！");return null;}};public static void main(String[] args){new Thread(new MyIntegerTask("IntegerTask1")).start();new Thread(new MyStringTask("StringTask1")).start();new Thread(new MyIntegerTask("IntegerTask2")).start();new Thread(new MyStringTask("StringTask2")).start();}public static class MyIntegerTask implements Runnable{private String name;MyIntegerTask(String name){this.name = name;}@Overridepublic void run() {for(int i = 0; i < 5; i++){// ThreadLocal.get方法获取线程变量if(null == MyThreadLocal.threadLocal.get()){// ThreadLocal.et方法设置线程变量MyThreadLocal.threadLocal.set(0);System.out.println("线程" + name + ": 0");}else{int num = (Integer)MyThreadLocal.threadLocal.get();MyThreadLocal.threadLocal.set(num + 1);System.out.println("线程" + name + ": " + MyThreadLocal.threadLocal.get());if(i == 3){MyThreadLocal.threadLocal.remove();}}try{Thread.sleep(1000);}catch (InterruptedException e){e.printStackTrace();}}   }}public static class MyStringTask implements Runnable{private String name;MyStringTask(String name){this.name = name;}@Overridepublic void run() {for(int i = 0; i < 5; i++){if(null == MyThreadLocal.threadLocal.get()){MyThreadLocal.threadLocal.set("a");System.out.println("线程" + name + ": a");}else{String str = (String)MyThreadLocal.threadLocal.get();MyThreadLocal.threadLocal.set(str + "a");System.out.println("线程" + name + ": " + MyThreadLocal.threadLocal.get());}try{Thread.sleep(800);}catch (InterruptedException e){e.printStackTrace();}}}}
<strong>}
</strong>

调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！
线程IntegerTask1: 0
调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！
线程IntegerTask2: 0
调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！
调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！
线程StringTask1: a
线程StringTask2: a
线程StringTask1: aa
线程StringTask2: aa
线程IntegerTask1: 1
线程IntegerTask2: 1
线程StringTask1: aaa
线程StringTask2: aaa
线程IntegerTask2: 2
线程IntegerTask1: 2
线程StringTask2: aaaa
线程StringTask1: aaaa
线程IntegerTask2: 3
线程IntegerTask1: 3
线程StringTask1: aaaaa
线程StringTask2: aaaaa
调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！
线程IntegerTask2: 0
调用get方法时，当前线程共享变量没有设置，调用initialValue获取默认值！
线程IntegerTask1: 0