缓存注解概念
|
名称 |
解释 |
| Cache | 缓存接口，定义缓存操作。实现有：RedisCache、EhCacheCache、ConcurrentMapCache等 |
| CacheManager | 缓存管理器，管理各种缓存（cache）组件 |
| @Cacheable | 主要针对方法配置，能够根据方法的请求参数对其进行缓存 |
| @CacheEvict | 清空缓存 |
| @CachePut | 保证方法被调用，又希望结果被缓存与@Cacheable区别在于是否每次都调用方法，常用于更新 |
| @EnableCaching | 开启基于注解的缓存 |
| keyGenerator | 缓存数据时key生成策略 |
| serialize | 缓存数据时value序列化策略 |
| @CacheConfig | 统一配置本类的缓存注解的属性 |
安装docker、redis
安装docker
yum -y install docker-ce
开机启动docker
systemctl start docker
检验docker是否安装成功
docker version
docker安装redis
docker pull redis
docker检测是否安装成功redis
docker images
docker启动redis并设置端口映射（-d表示后台运行）
docker run -p 6379:6379 -d redis:latest myredis
查看redis是否启动成功
docker ps
代码实现
在看代码前先看看目录结构吧（在这里使用ssm来整合redis）
数据库表结构
pom.xml文件，这里主要是引入spring-boot-starter-cache依赖
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <!-- mybatis 与 spring boot 2.x的整合包 --> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> <!--mysql JDBC驱动 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.39</version> </dependency> </dependencies>
配置文件application.yml，配置redis
spring:
datasource:
url: jdbc:mysql://localhost:3306/spring_boot_cache?useUnicode=true
driver-class-name: com.mysql.jdbc.Driver
username: root
password: lzh
redis:
# 这是redis所在服务器的ip
host: 192.168.126.129
timeout: 10000ms
database: 0
lettuce:
pool:
max-wait: -1ms
max-active: 8
max-idle: 8
min-idle: 0
cache:
type: redis
启动类加入@EnableCaching注解
package com.lzh.springbootstudytestcache;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
@SpringBootApplication
@EnableCaching
public class SpringBootStudyTestCacheApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootStudyTestCacheApplication.class, args);
}
}
UserController 类暴露接口
package com.lzh.springbootstudytestcache.controller;
import com.lzh.springbootstudytestcache.model.User;
import com.lzh.springbootstudytestcache.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
/**
* @author lzh
* create 2019-09-24-20:34
*/
@RestController
public class UserController {
@Autowired
UserService userService;
@GetMapping("/user/save")
public User saveUser(@RequestParam Integer id,@RequestParam String name,@RequestParam Integer age){
User user= userService.save(new User(id,name,age));
return user;
}
@GetMapping("/user/{id}")
public User getUserById(@PathVariable Integer id){
System.out.println("id="+id);
User user = userService.findUserById(id);
System.out.println("getUserById - "+user);
return user;
}
@GetMapping("/user/update")
public User updateUser(@RequestParam Integer id,@RequestParam String name,@RequestParam Integer age){
User user= userService.updateUser(new User(id,name,age));
return user;
}
@GetMapping("/user/del/{id}")
public String deleteUser(@PathVariable Integer id){
System.out.println("id="+id);
int num = userService.deleteUser(id);
if (num > 0){
return "删除成功";
} else {
return "删除失败";
}
}
}
UserService接口package com.lzh.springbootstudytestcache.service;
import com.lzh.springbootstudytestcache.model.User;
/**
* @author lzh
* create 2019-09-24-9:14
*/
public interface UserService {
User save(User user);
User findUserById(Integer id);
User updateUser(User user);
int deleteUser(Integer id);
}
UserService实现类
package com.lzh.springbootstudytestcache.service.impl;
import com.lzh.springbootstudytestcache.mapper.UserMapper;
import com.lzh.springbootstudytestcache.model.User;
import com.lzh.springbootstudytestcache.service.UserService;
import lombok.extern.log4j.Log4j2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
/**
* @author lzh
* create 2019-09-24-9:14
*/
@Service
@Log4j2
public class UserServiceImpl implements UserService {
@Autowired
UserMapper userMapper;
@Cacheable(value = "user",key = "#user.id")
@Override
public User save(User user) {
int saveNum = userMapper.saveUser(user);
System.out.println("saveNum="+saveNum);
return user;
}
@Cacheable(value = "user",key = "#id")
@Override
public User findUserById(Integer id) {
log.info("进入findUserById方法");
return userMapper.findUserById(id);
}
@CachePut(value = "user", key = "#user.id")
@Override
public User updateUser(User user) {
int num = userMapper.updateUser(user);
System.out.println("num="+num);
return user;
}
@CacheEvict(value = "user")
@Override
public int deleteUser(Integer id) {
return userMapper.deleteUser(id);
}
}
User实体类，加入@Data相当于加入getset方法，@AllArgsConstructor全参构造方法，@ToString重写tostring方法，引入Lombok简化代码
package com.lzh.springbootstudytestcache.model;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.ToString;
import java.io.Serializable;
/**
* @author Levin
* @since 2018/5/10 0007
*/
@Data
@AllArgsConstructor
@ToString
public class User implements Serializable {
private Integer id;
private String name;
private Integer age;
}
UserMapper持久层，使用mybatis注解@Select、@Update、@Insert、@Delete实现
package com.lzh.springbootstudytestcache.mapper;
import com.lzh.springbootstudytestcache.model.User;
import org.apache.ibatis.annotations.*;
/**
* @author lzh
* create 2019-09-24-20:39
*/
@Mapper
public interface UserMapper {
@Select("SELECT * FROM User WHERE id = #{id}")
User findUserById(Integer id);
@Update("update user set name=#{name},age=#{age} where id=#{id}")
int updateUser(User user);
@Insert("insert into user set name=#{name},age=#{age}")
int saveUser(User user);
@Delete("DELETE FROM USER WHERE id=#{id}")
int deleteUser(Integer id);
}
改变默认jdk序列化器
package com.lzh.springbootstudytestcache.config;
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.*;
/**
* @author lzh
* create 2019-09-24-22:22
*/
import org.springframework.cache.CacheManager;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
import java.time.Duration;
//@Configuration
public class MyRedisConfig {
//@Bean(name = "redisTemplate")
public RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory redisConnectionFactory){
RedisTemplate<String,Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
redisTemplate.setKeySerializer(keySerializer());
redisTemplate.setHashKeySerializer(keySerializer());
redisTemplate.setValueSerializer(valueSerializer());
redisTemplate.setHashValueSerializer(valueSerializer());
return redisTemplate;
}
//@Primary
//@Bean
public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory){
//缓存配置对象
RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();
redisCacheConfiguration = redisCacheConfiguration.entryTtl(Duration.ofMinutes(30L)) //设置缓存的默认超时时间：30分钟
.disableCachingNullValues() //如果是空值，不缓存
.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(keySerializer())) //设置key序列化器
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer((valueSerializer()))); //设置value序列化器
return RedisCacheManager
.builder(RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory))
.cacheDefaults(redisCacheConfiguration).build();
}
private RedisSerializer<String> keySerializer() {
return new StringRedisSerializer();
}
private RedisSerializer<Object> valueSerializer() {
return new GenericJackson2JsonRedisSerializer();
}
}
测试
启动srpingboot访问http://localhost:8080/user/1
使用redis可视化工具查看发现多了一个user对象，这就是在执行查询语句的时候保存的缓存
看控制台这里打印出了日志，这是第一次查询，说明执行了sql语句
再次访问http://localhost:8080/user/1，没有执行findUserById方法说明没有执行sql语句，而是直接从redis缓存中读取
