读写锁(独占锁，共享锁)-手写缓存

package com.demo.lock;


import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

class MyCache   //资源类
{
    //手动实现缓存基本都要 volatile 修饰
   private volatile Map<String,Object> map=new HashMap<>();
   private ReentrantReadWriteLock rwLock=new ReentrantReadWriteLock();

   public void put(String key,Object value){

       rwLock.writeLock().lock();//独占锁
       System.out.println(Thread.currentThread().getName()+"正在写入……");
       try {
           TimeUnit.MILLISECONDS.sleep(300);
           map.put(key,value);
           System.out.println(Thread.currentThread().getName()+"写入完成*****");
       } catch (InterruptedException e) {
           e.printStackTrace();
       }finally {
           rwLock.writeLock().unlock();
       }


   }
    public void get(String key){

        rwLock.readLock().lock();//共享锁
        System.out.println(Thread.currentThread().getName()+"正在读取……");
        try {
            TimeUnit.MILLISECONDS.sleep(300);
            Object value = map.get(key);
            System.out.println(Thread.currentThread().getName()+"读取完毕："+value);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            rwLock.readLock().unlock();
        }
    }
}

public class ShareLock {

    public static void main(String[] args) {
        MyCache myCache=new MyCache();

        for (int i = 1; i <5 ; i++) {
            final int tempInt=i;
            new Thread(()->{
                myCache.put(tempInt+"",tempInt+"");
            },String.valueOf(i)).start();

        }
        for (int i = 1; i <5 ; i++) {
            final int tempInt=i;
            new Thread(()->{
                myCache.get(tempInt+"");
            },String.valueOf(i)).start();

        }


    }


}