背景:
最近在项目用到了ThreadLocal,存放一些值。起线程异步获取ThreadLocal中的值,得到null。这是由于,ThreadLocal.get()会获取当前线程的一个map对象,以ThreadLocal为key获取对象。
demo:
这里定义了一个Person类,使用两个线程,一个向threadlocal set(),两个线程都使用threadLocal.get()获取存放的对象
其中一个线程没有获取到值
/**
* Created by GuanXF on 2017/12/8.
*/
public class ThreadLocalTest {
private static ThreadLocal<Person> personThreadLocal = new ThreadLocal<Person>(); public static void main(String[] args) throws InterruptedException {
Thread t1 = new Thread(new Runnable() {
public void run() {
Person gxf = new Person("Gxf", 18);
personThreadLocal.set(gxf);
System.out.println("From threadlocal : " + personThreadLocal.get());
}
});
Thread t2 = new Thread(new Runnable() {
public void run() {
System.out.println("From threadlocal : " + personThreadLocal.get());
}
});
t1.start();
t1.join();
t2.start(); } //Person实体类
static class Person{
private String name;
private int age; public Person(String name, int age) {
this.name = name;
this.age = 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;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
}