ThreadLocal类 线程间共享变量的应用

import java.util.HashMap; 

 import java.util.Map; 

 import java.util.Random; 



 public class ThreadLocalTest { 



private static ThreadLocal<Integer> x = new ThreadLocal<Integer>(); 

private static ThreadLocal<MyThreadScopeData> myThreadScopeData = new ThreadLocal<MyThreadScopeData>(); 

public static void main(String[] args) { 

for(int i=0;i<2;i++){ 

new Thread(new Runnable(){ 

@Override 

public void run() { 

int data = new Random().nextInt(); 

System.out.println(Thread.currentThread().getName()  

+ " has put data :" + data); 

x.set(data); 

 /* 
 MyThreadScopeData myData = new MyThreadScopeData(); 

myData.setName("name" + data); 

myData.setAge(data); 

myThreadScopeData.set(myData);*/ 

MyThreadScopeData.getThreadInstance().setName("name" + data); 

MyThreadScopeData.getThreadInstance().setAge(data); 

new A().get(); 

new B().get(); 

} 

}).start(); 

} 

} 

 

static class A{ 

public void get(){ 

int data = x.get(); 

System.out.println("A from " + Thread.currentThread().getName()  

+ " get data :" + data); 

 /* 
 MyThreadScopeData myData = myThreadScopeData.get();; 

System.out.println("A from " + Thread.currentThread().getName()  

+ " getMyData: " + myData.getName() + "," + 

myData.getAge());*/ 

MyThreadScopeData myData = MyThreadScopeData.getThreadInstance(); 

System.out.println("A from " + Thread.currentThread().getName()  

+ " getMyData: " + myData.getName() + "," + 

myData.getAge()); 

} 

} 

 

static class B{ 

public void get(){ 

int data = x.get(); 
 

System.out.println("B from " + Thread.currentThread().getName()  

+ " get data :" + data); 

MyThreadScopeData myData = MyThreadScopeData.getThreadInstance(); 

System.out.println("B from " + Thread.currentThread().getName()  

+ " getMyData: " + myData.getName() + "," + 

myData.getAge()); 
 

} 
  

} 

 } 



 class MyThreadScopeData{ 

private MyThreadScopeData(){} 

public static /*synchronized*/ MyThreadScopeData getThreadInstance(){ 

MyThreadScopeData instance = map.get(); 

if(instance == null){ 

instance = new MyThreadScopeData(); 

map.set(instance); 

} 

return instance; 

} 

//private static MyThreadScopeData instance = null;//new MyThreadScopeData(); 

private static ThreadLocal<MyThreadScopeData> map = new ThreadLocal<MyThreadScopeData>(); 

 

private String name; 

private int age; 

public String getName() { 

return name; 

} 

public void setName(String name) { 

this.name = name; 

} 

public int getAge() { 

return age; 

} 

public void setAge(int age) { 

this.age = age; 

} 

 }