@CachePut更新数据库和缓存

时间:2022-05-23 王某人i 人气:0

关于更新缓存，要注意两点

1、@Cacheable的key

要和@CachePut 的key一致

比如：

  @Cacheable(key = "'userCache'") //缓存,
    public Uuser findByEmail(String email) { 
        System.err.println("执行这里，说明缓存中读取不到数据，直接读取数据库....");
        return redisMapper.findByEmail(email);
    }
  @CachePut(key = "'userCache'") //userCache要加‘'单引号，表示这是一个字符串
    public Uuser updateSelf(String nickname, String email) {
        System.err.println("执行这里，更新数据库，更新缓存....");
        uuserMapper.updateSelf(nickname, email);
        Uuser uuser = redisMapper.findByEmail(email); 
        return uuser;  
    }

2、@CachePut的返回值

要和@Cacheable的返回值一样

如果@Cacheable 返回的是一个对象，@CachePut 返回也要是对象，否则会报类型转换异常，如上代码返回的都是 Uuser.

缓存的CachePut冲突Cacheable

CachePut 跟 Cacheable放在一起， Cacheable的效果就跟 CachePut 一样的，每次都会去查数据库，虽然有缓存。

/**
 *
 * @param id
 * @return
 */
@Caching( put = {
        @CachePut(key = "T(cn.a.b.constant.RedisKey).OPEN_MEDIUM_INFO + #result.mediumBankCard", unless="#result.mediumBankCard==null or #result.status !='2'"),
        @CachePut(key = "T(a.b.c.constant.RedisKey).ACCOUNT_CODE + #result.accountCode", unless="!{'0','1','2','3'}.contains(#result.mediumStatus)"),
        @CachePut(key = "T(a.b.c.constant.RedisKey).CERT_NO+ #result.certNo", unless="#result.certNo==null or !{'0','1','2','3'}.contains(#result.status)")
}
, cacheable = {@Cacheable(key="T(a.b.c.constant.RedisKey).ID  + #id")}
)
public XXXInfo selectByPrimaryKey(Long id){
    return mapper.selectByPrimaryKey(id);
}

可以分解成两个

Service.java
/**
 *
 * @param id
 * @return
 */
@Caching( put = {
        @CachePut(key = "T(cn.a.b.constant.RedisKey).OPEN_MEDIUM_INFO + #result.mediumBankCard", unless="#result.mediumBankCard==null or #result.status !='2'"),
        @CachePut(key = "T(a.b.c.constant.RedisKey).ACCOUNT_CODE + #result.accountCode", unless="!{'0','1','2','3'}.contains(#result.mediumStatus)"),
        @CachePut(key = "T(a.b.c.constant.RedisKey).CERT_NO+ #result.certNo", unless="#result.certNo==null or !{'0','1','2','3'}.contains(#result.status)")
}
)
public XXXInfo selectByPrimaryKey(Long id){
    return mapper.selectByPrimaryKey(id);
} 

Mapper.java
{
    @Cacheable(key="T(a.b.c.constant.RedisKey).ID  + #p0")
    XXXXInfo selectByPrimaryKey(Long id);
}

mybatis 接口类参数。用#参数名无效。只能用#p0, #p1

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。

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