1 /**
 2  * 线程范围类的数据共享
 3  * 核心：ThreadLocal类
 4  * 实际场景：
 5  * Hibernate的getCurrentSession方法，就是从线程范围内获取存在的session,如果不存在则新建一个并绑定到线程上
 6  * struts将一个请求里的所有参数绑定到一个线程范围内的对象里
 7  * @author yzl
 8  *
 9  */
10 public class ThreadPart_4 {
11     public static void main(String[] args) {
12         new Thread(new Runnable() {
13             public void run() {
14                 MyThreadLocalObj obj = MyThreadLocalObj.getInstance();
15                 while(obj.getData()<20){
16                     obj.add();
17                     System.out.println(Thread.currentThread().getName() + " after add method value :" + obj.getData());
18                     //这里操作其实就是同一个MyThreadLocalObj对象
19                     new MyAdd().add();
20                     System.out.println(Thread.currentThread().getName() + " after MyAdd add method value :" + obj.getData());
21                     try {
22                         Thread.sleep(1000);
23                     } catch (InterruptedException e) {
24                         e.printStackTrace();
25                     }
26                 }
27             }
28         }).start();
29
30         new Thread(new Runnable() {
31             public void run() {
32                 MyThreadLocalObj obj = MyThreadLocalObj.getInstance();
33                 while(obj.getData()>0){
34                     obj.sub();
35                     System.out.println(Thread.currentThread().getName() + " after sub method value :" + obj.getData());
36                     //这里操作其实就是同一个MyThreadLocalObj对象
37                     new MySub().sub();
38                     System.out.println(Thread.currentThread().getName() + " after MySub sub method value :" + obj.getData());
39                     try {
40                         Thread.sleep(1000);
41                     } catch (InterruptedException e) {
42                         e.printStackTrace();
43                     }
44                 }
45             }
46         }).start();
47     }
48 }
49
50 class MyAdd{
51     public void add(){
52         MyThreadLocalObj.getInstance().add();
53     }
54 }
55
56 class MySub{
57     public void sub(){
58         MyThreadLocalObj.getInstance().sub();
59     }
60 }
61
62 /**
63  * 单例模式下的
64  * 线程范围内共享
65  * 线程范围外互不影响
66  * @author yzl
67  *
68  */
69 class MyThreadLocalObj{
70     private int data = 10;
71
72     public void add(){
73         data++;
74     }
75
76     public void sub(){
77         data--;
78     }
79
80     private MyThreadLocalObj(){};
81     private static ThreadLocal<MyThreadLocalObj> local = new ThreadLocal<MyThreadLocalObj>();
82
83
84     public static MyThreadLocalObj getInstance(){
85         if(local.get() == null){
86             local.set(new MyThreadLocalObj());
87         }
88         return local.get();
89     }
90
91     public int getData() {
92         return data;
93     }
94 }

 1 Thread-0 after add method value :11
 2 Thread-1 after sub method value :9
 3 Thread-0 after MyAdd add method value :12
 4 Thread-1 after MySub sub method value :8
 5 Thread-1 after sub method value :7
 6 Thread-0 after add method value :13
 7 Thread-1 after MySub sub method value :6
 8 Thread-0 after MyAdd add method value :14
 9 Thread-1 after sub method value :5
10 Thread-0 after add method value :15
11 Thread-1 after MySub sub method value :4
12 Thread-0 after MyAdd add method value :16
13 Thread-0 after add method value :17
14 Thread-1 after sub method value :3
15 Thread-0 after MyAdd add method value :18
16 Thread-1 after MySub sub method value :2
17 Thread-0 after add method value :19
18 Thread-0 after MyAdd add method value :20
19 Thread-1 after sub method value :1
20 Thread-1 after MySub sub method value :0