java线程范围内的数据共享

1.不使用ThreadLocal，自己定义一个map，用来存放当前线程的数据

package com.norelax.www;

import java.util.Map;
import java.util.Random;
import java.util.concurrent.ConcurrentHashMap;

public class ThreadScopeDataShare {
	//不使用ThreadLocal，自己定义一个map，用来存放当前线程的数据
	public static Map<Thread, Integer> threadData=new ConcurrentHashMap<Thread, Integer>();
	public static void main(String[] args) {
		//开启两个线程，分别向threadData放数据
		for (int i = 1; i <=2; i++) {
			new Thread(new Runnable() {
				public void run() {
					int data = new Random().nextInt();
					System.out.println(Thread.currentThread().getName()+"has put data:"+data);
					//放入数据
					threadData.put(Thread.currentThread(),data);
					//获取数据
					new A().getData();
					new B().getData();
				}
			}).start();
		}
		
	}
	
	static class A {
		public void getData() {
			Integer data = threadData.get(Thread.currentThread());
			System.out.println("A from" + Thread.currentThread().getName() + "get data :"
					+ data);
		}
	}
	
	static class B {
		public void getData() {
			Integer data = threadData.get(Thread.currentThread());
			System.out.println("B from" + Thread.currentThread().getName() + "get data :"
					+ data);
		}
	}


}

特别要注意，这里面的  class A和 class B都是static类型的，不然在编译时出现

No enclosing instance of type ThreadScopeDataShare is accessible. Must qualify the allocation with an enclosing instance of type ThreadScopeDataShare (e.g. x.new A() 
 where x is an instance of ThreadScopeDataShare).

因为类A和类B都是在static方法中被调用
效果如下：

Thread-1has put data:1766462033
Thread-0has put data:1524868127
A fromThread-0get data :1524868127
A fromThread-1get data :1766462033
B fromThread-0get data :1524868127
B fromThread-1get data :1766462033

2.使用ThreadLocal保证线程范围内的数据共享

简单粗暴，直接上代码：

package com.norelax.www;

import java.util.Random;

import com.norelax.www.ThreadScopeDataShare.A;
import com.norelax.www.ThreadScopeDataShare.B;

public class ThreadLocalTest {
	private static ThreadLocal<Integer> shareData = new ThreadLocal<Integer>();

	public static void main(String[] args) {
		for (int i = 1; i <= 2; i++) {
			new Thread(new Runnable() {
				public void run() {
					int data = new Random().nextInt();
					System.out.println(Thread.currentThread().getName()
							+ "has put data:" + data);
					//输入数据
					shareData.set(data);
					//获取数据
					new A().getData();
					new B().getData();
				}
			}).start();
		}
	}

	static class A {
		public void getData() {
			Integer data = shareData.get();
			System.out.println("A from" + Thread.currentThread().getName()
					+ "get data :" + data);
		}
	}

	static class B {
		public void getData() {
			Integer data = shareData.get();
			System.out.println("B from" + Thread.currentThread().getName()
					+ "get data :" + data);
		}
	}

}

结果如下：

Thread-1has put data:-2027879383
Thread-0has put data:1157262527
A fromThread-0get data :1157262527
A fromThread-1get data :-2027879383
B fromThread-0get data :1157262527
B fromThread-1get data :-2027879383

3.如果共享的数据是对象呢？

package com.norelax.www;

import java.util.Random;


public class ThreadLocalObjectTest {

	public static void main(String[] args) {
		for (int i = 1; i <=2; i++) {
			new Thread(new Runnable() {
				public void run() {
					int data = new Random().nextInt();
					System.out.println(Thread.currentThread().getName() 
							+ " has put age :" + data+"has put name:norelax"+data);
					MyThreadScopeShareDate myThreadInstance = MyThreadScopeShareDate.getMyThreadInstance();
					myThreadInstance.setAge(data);
					myThreadInstance.setName("norelax"+data);
					new A().get();
					new B().get();
					
				}
			}).start();
		}
	}
	
	static class A{
		public void get(){
			MyThreadScopeShareDate myData = MyThreadScopeShareDate.getMyThreadInstance();
			System.out.println("A from " + Thread.currentThread().getName() 
					+ " getMyData: " + myData.getName() + "," +
					myData.getAge());
		}
	}
	
	static class B{
		public void get(){
			MyThreadScopeShareDate myData = MyThreadScopeShareDate.getMyThreadInstance();
			System.out.println("B from " + Thread.currentThread().getName() 
					+ " getMyData: " + myData.getName() + "," +
					myData.getAge());			
		}		
	}
	
}
//要共享的数据对象
class MyThreadScopeShareDate{
	private MyThreadScopeShareDate() {};
	private static ThreadLocal<MyThreadScopeShareDate> myThreadScopeShareDate=new ThreadLocal<MyThreadScopeShareDate>();
	<span style="color:#ff0000;">//单利模式获取对应实体
	public static MyThreadScopeShareDate getMyThreadInstance(){
		MyThreadScopeShareDate myThreadScopeShare = myThreadScopeShareDate.get();
		if (myThreadScopeShare==null) {
			myThreadScopeShare=new MyThreadScopeShareDate();
			myThreadScopeShareDate.set(myThreadScopeShare);
		}
		return myThreadScopeShare;
	}</span>
	
	private String name;
	private Integer age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	
}

结果如下：

Thread-1 has put age :-1848631193has put name:norelax-1848631193
Thread-0 has put age :542514109has put name:norelax542514109
A from Thread-0 getMyData: norelax542514109,542514109
A from Thread-1 getMyData: norelax-1848631193,-1848631193
B from Thread-1 getMyData: norelax-1848631193,-1848631193
B from Thread-0 getMyData: norelax542514109,542514109