代码语言：javascript复制
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;
/**
* @author: xiepanpan
* @Date: 2020/2/17
* @Description:
*/
@Service
public class RedisIncrService {
@Autowired
StringRedisTemplate redisTemplate;
private Object obj = new Object();
//这个锁大家都用一个。
//this当前对象。当前service对象。spring的组件是单例的。this一个。
//this相同，锁相同，锁ok
//RedisIncrService对象一个。自动注入；StringRedisTemplate，redisTemplate也只能注入唯一一个。
//RedisIncrService对象创建的时候赋值，RedisIncrService一个 private Object obj = new Object();
//1）、synchronized(this)：能
//2）、synchronized (redisTemplate)：能
//3）、synchronized (new Object())：锁不住
//4）、synchronized (obj)：锁得住？锁得住
//5）、synchronized (obj())；锁的住
//6）、synchronized (RedisIncrService.class)；锁得住
public void incr() {
synchronized (this){
ValueOperations<String, String> stringStringValueOperations = redisTemplate.opsForValue();
String num = stringStringValueOperations.get("num");
if(num!=null){
Integer i = Integer.parseInt(num);
i = i 1;
stringStringValueOperations.set("num",i.toString());
}
}
}
public Object obj() {
return obj;
}
//肯定锁不住
//public Object obj() {
// Object o = new Object();
// BeanUtils.copyProperties(obj, o);
// return o;
//}
}synchronized的锁是基于对象的 只要是同一个对象 锁就能起作用
代码语言：javascript复制import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;
/**
* @author: xiepanpan
* @Date: 2020/2/17
* @Description:
*/
@Service
public class RedisIncrService {
@Autowired
StringRedisTemplate redisTemplate;
ReentrantLock lock = new ReentrantLock();
public void incr() {
/**
* ReentrantLock lock = new ReentrantLock();应该在成员变量位置才锁得住
*/
//锁得住？
lock.lock();
ValueOperations<String, String> stringStringValueOperations = redisTemplate.opsForValue();
String num = stringStringValueOperations.get("num");
if (num != null) {
Integer i = Integer.parseInt(num);
i = i 1;
stringStringValueOperations.set("num", i.toString());
}
lock.unlock();
}
}ReentrantLock 应该在成员变量位置才锁得住
以上两种锁都是进程内的锁 单机跑，分布式肯定不好使
