ThreadLocal的简单使用

 package com.thread;

 public class ThreadLocalTest {
     public static void main(String[] args) {
         final Person p = new Person();
             new Thread(new Runnable() {
                 @Override
                 public void run() {
                     p.setName("zhangsan");
                     p.setAge(100);
                     try {
                         Thread.sleep(1000);
                     } catch (InterruptedException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                     System.out.println("1:"+p.getName());
                 }
             }).start();

             new Thread(new Runnable() {
                 @Override
                 public void run() {
                     p.setName("lisi");
                     p.setAge(20);
                     try {
                         Thread.sleep(1000);
                     } catch (InterruptedException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                     System.out.println("2:"+p.getName());
                 }
             }).start();
     }
 }

 class Person {
     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;
     }

 }

如上述执行结果：

1:lisi
2:lisi
多个线程共享同一个变量时，如果想让这个变量成为各自线程的一个副本(线程的局部变量),这样每个线程的数据就不会收到其他线程的影响

ThreadLocal很好的解决了这个问题

 package com.thread;

 public class ThreadLocalTest {
     public static void main(String[] args) {
             new Thread(new Runnable() {
                 @Override
                 public void run() {
                     Person.getThreadInstance().setName("zhangsan");
                     Person.getThreadInstance().setAge(100);
                     try {
                         Thread.sleep(1000);
                     } catch (InterruptedException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                     System.out.println("1:"+Person.getThreadInstance().getName());
                 }
             }).start();

             new Thread(new Runnable() {
                 @Override
                 public void run() {
                     getPerson().setName("lisi");
                     getPerson().setAge(20);
                     try {
                         Thread.sleep(1000);
                     } catch (InterruptedException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                     System.out.println("2:"+getPerson().getName());
                 }
             }).start();
     }

     public static Person getPerson(){
         return Person.getThreadInstance();
     }
 }

 class Person {
     private String name;
     private int age;
     private static ThreadLocal<Person> local = new ThreadLocal<>();
     private static Person p = null;
     private Person(){
     }
     //这儿可不需要synchonized
     public static Person getThreadInstance(){
         p = local.get();
         if(p==null){
             p = new Person();
             local.set(p);
         }
         return p;
     }
     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;
     }

 }