理解高并发(18).编写自己的threadlocal

李四 当前投票次数 :5

张三 当前投票次数 :4

李四 当前投票次数 :6

张三 当前投票次数 :5

李四 当前投票次数 :7

张三 当前投票次数 :6

李四 当前投票次数 :8

张三 当前投票次数 :7

李四 当前投票次数 :9

张三 当前投票次数 :8

李四 当前投票次数 :10

张三 当前投票次数 :9

李四 over

张三 当前投票次数 :10

张三 over

源码如下：

• MyThreadLocal.java

package com.test.thread.demo12;

import java.util.HashMap;

import java.util.Map;

public abstract class MyThreadLocal<T> {

public T get(){

MyThread thread = (MyThread) Thread.currentThread();

Map<String, Object> map = thread.map;

if(map == null){

thread.map = new HashMap<String, Object>();

thread.map.put(this.toString(), initValue());

return initValue();

}

return (T)thread.map.get(this.toString());

}

public void set(T t){

MyThread thread = (MyThread) Thread.currentThread();

Map<String, Object> map = thread.map;

if(map == null){

thread.map = new HashMap<String, Object>();

}

thread.map.put(this.toString(), t);

}

public void remove(){

//MyThread thread = (MyThread) Thread.currentThread();

//thread.map.clear();

}

abstract public T initValue();

}

• MyThread.java

package com.test.thread.demo12;

import java.util.Map;

public class MyThread extends Thread{

public Map<String, Object> map = null;

public MyThread(Runnable runnable){

super(runnable);

}

}

• Ticket.java

package com.test.thread.demo12;

public class Ticket {

MyThreadLocal<Integer> times = new MyThreadLocal<Integer>(){

@Override

public Integer initValue() {

return 0;

}

};

public void select() {

int t = times.get();

t++;

times.set(t);

System.out.println(Thread.currentThread().getName() + " 当前投票次数 :" + times.get());

if (times.get() == 10) {

System.out.println(Thread.currentThread().getName() + " over");

times.remove();

}

}

}

• TestClient.java

package com.test.thread.demo12;

public class TestClient {

public static void main(String[] args) {

final Ticket ticket = new Ticket();

Thread t = new MyThread(new Runnable(){

public void run(){

for(int j=0; j<10; j++){

ticket.select();

}

}

});

t.setName("张三");

Thread t2 = new MyThread(new Runnable(){

public void run(){

for(int j=0; j<10; j++){

ticket.select();

}

}

});

t2.setName("李四");

t.start();

t2.start();

}

}