import java.util.HashMap;import java.util.Map;import java.util.Random;

public class ThreadScopeShareData {

/**     *  多个线程访问同一个成员变量，因该是每一个线程拿到的变量是不同的     *  比如银行的转账     *  张三对李四     *  王五对赵六     *  如果成员变量不和线程绑定那么王五就可能在转账时操作张三的钱     *  如下程序因该是每个getData都要从自己的线程拿到自己的数据     *  然而实际情况并非如此*/

//    public static void main(String[] args) {////        for(int i=0;i<9;i++){//            new Thread(new Runnable(){//                @Override//                public void run() {//                    int data = new Random().nextInt();//                    System.out.println(Thread.currentThread().getName()+" has put data of " + data);//                    new A().getData();//                    new B().getData();//                }//                //            }).start();//        }//        //    }////    static class A{//        void getData(){//            System.out.println("A thread from "+Thread.currentThread().getName()+" get data of " + data);//        }//    }//    //    static class B{//        void getData(){//            System.out.println("B thread from "+Thread.currentThread().getName()+" get data of " + data);//            //        }//    }

/*     * 我们知道一个线程就对应一个数据，这就相当于map的key和value     * 把每个线程和对应的值填入一个map     * 下面就是一种解决方法*///    private static Map<Thread, Integer> dataMap = new HashMap<Thread, Integer>();//    public static void main(String[] args) {////        for(int i=0;i<9;i++){//            new Thread(new Runnable(){//                @Override//                public void run() {//                    int data = new Random().nextInt();//                    dataMap.put(Thread.currentThread(),data);//                    System.out.println(Thread.currentThread().getName()+" has put data of " + data);//                    new A().getData();//                    new B().getData();//                }//                //            }).start();//        }//        //    }////    static class A{//        void getData(){//            int data = dataMap.get(Thread.currentThread());//            System.out.println("A thread from "+Thread.currentThread().getName()+" get data of " + data);//        }//    }//    //    static class B{//        void getData(){//            int data = dataMap.get(Thread.currentThread());//            System.out.println("B thread from "+Thread.currentThread().getName()+" get data of " + data);//            //        }//    }

//    /*//     * java也提供了一个类来控制线程和变量之间的绑定：ThreadLocal//     * ThreadLocal就相当于上例的map//     *///    

//    private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>();//    public static void main(String[] args) {////        for(int i=0;i<9;i++){//            new Thread(new Runnable(){//                @Override//                public void run() {//                    int data = new Random().nextInt();////调用threadLocal.set();参数是要保存的数字//                    threadLocal.set(data);//                    System.out.println(Thread.currentThread().getName()+" has put data of " + data);//                    new A().getData();//                    new B().getData();//                }//                //            }).start();//        }//        //    }////    static class A{//        void getData(){////threadLocal.get()不用指定当前线程，他代表的就是当前线程//            int data = threadLocal.get();//            System.out.println("A thread from "+Thread.currentThread().getName()+" get data of " + data);//        }//    }//    //    static class B{//        void getData(){////threadLocal.get()不用指定当前线程，他代表的就是当前线程//            int data = threadLocal.get();//            System.out.println("B thread from "+Thread.currentThread().getName()+" get data of " + data);//            //        }//    }//    //    /*//     * 总结：一个threadLocal代表一个变量，故其中只能放一个数据，如果有两个变量要线程共享//     * 则要定义两个ThreadLocal对象，如果有很多的变量要共享，就可以考虑把这些变量封装//     * 然后在ThreadLocal中存储这个对象//     * 下面示例是多个变量//     */

/*     * 一个线程和多个变量之间的绑定*///    //    private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>();//    private static ThreadLocal<MyThreadScopeData> myThreadLocal = new ThreadLocal<MyThreadScopeData>();//    public static void main(String[] args) {////        for(int i=0;i<9;i++){//            new Thread(new Runnable(){//                @Override//                public void run() {//                    int data = new Random().nextInt();//                    threadLocal.set(data);//                    System.out.println(Thread.currentThread().getName()+" has put data of " + data);//                    //////                    MyThreadScopeData myData = new MyThreadScopeData();//                    myData.setName("name" + data);//                    myData.setAge(data);//                    myThreadLocal.set(myData);//                    //                    new A().getData();//                    new B().getData();//                }//                //            }).start();//        }//        //    }////    static class A{//        void getData(){//            int data = threadLocal.get();//            System.out.println("A thread from "+Thread.currentThread().getName()+" get data " + data);//            //            MyThreadScopeData myData = myThreadLocal.get();//            System.out.println("A thread from "+Thread.currentThread().getName()+" get data " + myData.getAge() + " , " +myData.getAge());//        }//    }//    //    static class B{//        void getData(){//            int data = threadLocal.get();//            System.out.println("B thread from "+Thread.currentThread().getName()+" get data " + data);//            //            MyThreadScopeData myData = myThreadLocal.get();//            System.out.println("B thread from "+Thread.currentThread().getName()+" get data " + myData.getAge() + " , " +myData.getAge());//            //        }//    }//    //    /*//     * 首先定义一个类封装数据//     *///    static 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;//        }//    }

//一种更为优雅的实现方式,可以隐藏ThreadLocal    private static ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>();public static void main(String[] args) {

for(int i=0;i<9;i++){new Thread(new Runnable(){                @Overridepublic void run() {int data = new Random().nextInt();                    threadLocal.set(data);                    System.out.println(Thread.currentThread().getName()+" has put data of " + data);

                    MyThreadScopeData.getInstance().setName("name is "+data);                    MyThreadScopeData.getInstance().setAge(data);

new A().getData();new B().getData();                }

            }).start();        }

    }

static class A{void getData(){int data = threadLocal.get();            System.out.println("A thread from "+Thread.currentThread().getName()+" get data " + data);

            MyThreadScopeData myData = MyThreadScopeData.getInstance();            System.out.println("A thread from "+Thread.currentThread().getName()+" get data " + myData.getAge() + " , " +myData.getAge());        }    }

static class B{void getData(){int data = threadLocal.get();            System.out.println("B thread from "+Thread.currentThread().getName()+" get data " + data);

            MyThreadScopeData myData = MyThreadScopeData.getInstance();            System.out.println("B thread from "+Thread.currentThread().getName()+" get data " + myData.getAge() + " , " +myData.getAge());

        }    }

/*     * 实现这个类的单例*/static class MyThreadScopeData{/*饱汉模式创建单例        private MyThreadScopeData(){}        private static MyThreadScopeData instance = new MyThreadScopeData();        public synchronized MyThreadScopeData getInstance(){            return instance;        }*/

/* 饥汉模式创建单例        private MyThreadScopeData(){}        private static MyThreadScopeData instance = null;        public synchronized MyThreadScopeData getInstance(){            if(instance == null){                instance = new MyThreadScopeData();            }            return instance;        }*/

//将ThreadLocal放在了单例的实现里，外部就不用了解内部的实现，外部的调用自然就是与线程有关的实例        private MyThreadScopeData(){}//        private static MyThreadScopeData instance = null;        private static ThreadLocal<MyThreadScopeData> local = new ThreadLocal<MyThreadScopeData>();public static /*synchronized就可以不用了*/ MyThreadScopeData getInstance(){            MyThreadScopeData instance= local.get();if(instance == null){                instance = new MyThreadScopeData();                local.set(instance);            }return instance;        }

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;        }    }}