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();
}
}
}
