ThreadLocal实现线程范围内的共享变量

ThreadLocal变量自动与当前线程相关联，替代Map，HashMap结构：

package cn.qy.heima2;import java.util.Random;public class ThreadLocalTest
{private static ThreadLocal<Integer> xLocal= new ThreadLocal<Integer>();public static void main(String[] args) {// TODO Auto-generated method stubfor(int i=0;i<2;i++){new Thread(new Runnable() {                @Overridepublic void run() {// TODO Auto-generated method stubint data=new Random().nextInt();                System.out.println(Thread.currentThread().getName()+"has put data:"+data);        xLocal.set(data);   //xLocal与当前线程相关，进行数据存放                                new A().get();new B().get();}}).start(); }}
static class A
{
public void get()
{
int data=xLocal.get();       //xLocal与当前线程相关，进行数据取出
System.out.println("A from"+Thread.currentThread().getName()+"get data:"+data);
}
}
static class B
{
public void get()
{
int data=xLocal.get();
System.out.println("B from"+Thread.currentThread().getName()+"get data:"+data);
}
}
}

将多个共享变量封装为一个对象放入ThreadLocal变量里面：

package cn.qy.heima2;
import java.util.Random;
public class ThreadLocalTest
{private static ThreadLocal<Integer> xLocal= new ThreadLocal<Integer>();private static ThreadLocal<MyThreadScopeData> mythreadScopedata=new ThreadLocal<MyThreadScopeData>();public static void main(String[] args) {// TODO Auto-generated method stubfor(int i=0;i<2;i++){new Thread(new Runnable() {                @Overridepublic void run() {// TODO Auto-generated method stubint data=new Random().nextInt();                System.out.println(Thread.currentThread().getName()+"has put data:"+data);        xLocal.set(data);   //xLocal与当前线程相关，进行数据存放MyThreadScopeData mydata= new MyThreadScopeData();mydata.setName("qianyong"+data);mydata.setAge(data);mythreadScopedata.set(mydata);new A().get();new B().get();}}).start(); }}
static class A
{
public void get()
{
int data=xLocal.get();       //xLocal与当前线程相关，进行数据取出
System.out.println("A from"+Thread.currentThread().getName()+"get data:"+data);
MyThreadScopeData mydata=mythreadScopedata.get();
System.out.println("A from"+Thread.currentThread().getName()+",get myName:"+mydata.getName()+",get myAge:"+mydata.getAge());
}
}
static class B
{
public void get()
{
int data=xLocal.get();
System.out.println("B from"+Thread.currentThread().getName()+"get data:"+data);
MyThreadScopeData mydata=mythreadScopedata.get();
System.out.println("B from"+Thread.currentThread().getName()+",get myName:"+mydata.getName()+",get myAge:"+mydata.getAge());
}
}
}class 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;
}
}

运行结果：

Thread-0has put data:-2141728227
Thread-1has put data:1848865996
A fromThread-1get data:1848865996
A fromThread-1,get myName:qianyong1848865996,get myAge:1848865996
A fromThread-0get data:-2141728227
A fromThread-0,get myName:qianyong-2141728227,get myAge:-2141728227
B fromThread-1get data:1848865996
B fromThread-1,get myName:qianyong1848865996,get myAge:1848865996
B fromThread-0get data:-2141728227
B fromThread-0,get myName:qianyong-2141728227,get myAge:-2141728227

通过ThreadLocal变量创建与某一线程相关联的单例对象：

package cn.qy.heima2;
import java.util.Random;
public class ThreadLocalTest
{private static ThreadLocal<Integer> xLocal= new ThreadLocal<Integer>();private static ThreadLocal<MyThreadScopeData> mythreadScopedata=new ThreadLocal<MyThreadScopeData>();public static void main(String[] args) {// TODO Auto-generated method stubfor(int i=0;i<2;i++){new Thread(new Runnable() {                @Overridepublic void run() {// TODO Auto-generated method stubint data=new Random().nextInt();                System.out.println(Thread.currentThread().getName()+"has put data:"+data);        xLocal.set(data);   //xLocal与当前线程相关，进行数据存放/*MyThreadScopeData mydata= new MyThreadScopeData();mydata.setName("qianyong"+data);mydata.setAge(data);mythreadScopedata.set(mydata);*/MyThreadScopeData.getThreadInstance().setName("qianyong"+data);MyThreadScopeData.getThreadInstance().setAge(data);new A().get();new B().get();}}).start(); }}
static class A
{
public void get()
{
int data=xLocal.get();         //xLocal与当前线程相关，进行数据取出
System.out.println("A from"+Thread.currentThread().getName()+",get data:"+data);
/*MyThreadScopeData mydata=mythreadScopedata.get();
System.out.println("A from"+Thread.currentThread().getName()+",get myName:"+mydata.getName()+",get myAge:"+mydata.getAge());*/
MyThreadScopeData mydata=MyThreadScopeData.getThreadInstance();
System.out.println("A from"+Thread.currentThread().getName()+",get myName:"+mydata.getName()+",get myAge:"+mydata.getAge());
}
}
static class B
{
public void get()
{
int data=xLocal.get();
System.out.println("B from"+Thread.currentThread().getName()+",get data:"+data);
/*MyThreadScopeData mydata=mythreadScopedata.get();
System.out.println("B from"+Thread.currentThread().getName()+",get myName:"+mydata.getName()+",get myAge:"+mydata.getAge());*/
MyThreadScopeData mydata=MyThreadScopeData.getThreadInstance();
System.out.println("B from"+Thread.currentThread().getName()+",get myName:"+mydata.getName()+",get myAge:"+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;
//创建单例,饥汉模式   //new MyThreadScopeData(); 创建单例，饱汉模式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;
}
}

转载于:https://www.cnblogs.com/dddyg/p/10715760.html

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