SpringBoot与SpringCache

SpringBoot与SpringCache

1.SpringCache的概念2.SpringCache用法（redis版）

2.1 .SpringCache基本用法2.2 .SpringCache自定义缓存key2.3 .SpringCache更新缓存2.4 .SpringCache清空缓存2.5 .SpringCache其他用法 3.SpringCache用法（EhCache版） 1.SpringCache的概念

首先我们知道jpa,jdbc这些东西都是一些规范，比如jdbc，要要连接到数据库，都是需要用到数据库连接，预处理，结果集这三个对象，无论是连接到mysql还是oracle都是需要用到这个三个对象的，这是一种规范，而SpringCache是一种作为缓存的规范，具体实现有redis,EhCahe等

2.SpringCache用法（redis版） 2.1 .SpringCache基本用法

1.pom.xml

<?xml version="1.0" encoding="UTF-8"?> 4.0.0 org.springframework.boot spring-boot-starter-parent 2.6.3 com.yl cache_redis 0.0.1-SNAPSHOT cache_redis Demo project for Spring Boot 11 org.springframework.boot spring-boot-starter-cache org.springframework.boot spring-boot-starter-data-redis org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test org.springframework.boot spring-boot-maven-plugin

2.application.properties

# redis的配置spring.redis.host=192.168.244.135spring.redis.port=6379spring.redis.password=root123

3.实体类

package com.yl.cache_redis.domain;import java.io.Serializable;public class User implements Serializable { private Integer id; private String username; private String password; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + ''' + ", password='" + password + ''' + '}'; }}

4.service

package com.yl.cache_redis;import com.yl.cache_redis.domain.User;import org.springframework.cache.annotation.Cacheable;import org.springframework.stereotype.Service;@Servicepublic class UserService { @Cacheable(cacheNames = "u1") //这个注解作用就是将方法的返回值存到缓存中 public User getUserById(Integer id) { System.out.println("getUserById:" + id); User user = new User(); user.setId(id); user.setUsername("root"); user.setPassword("root"); return user; }}

5.主程序，加上开启缓存的注解

package com.yl.cache_redis;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cache.annotation.EnableCaching;@SpringBootApplication@EnableCaching //开启缓存功能public class CacheRedisApplication { public static void main(String[] args) { SpringApplication.run(CacheRedisApplication.class, args); }}

6.测试

6.1）userservice没加@Cacheable注解时

6.2）userservice加@Cacheable注解后，发现sevice中的方法只调用了一次

6.3）在redis中也可以看到缓存中有数据，key为定义好的cacheNames+::+方法的参数

2.2 .SpringCache自定义缓存key

1.SpringCache默认使用cacheNames和方法中的参数结合组成key的，那么如果有多个参数呢？它又是如何组成key的呢？我们可以指定key吗？

2.如何自定义key呢？
1）自定义key

package com.yl.cache_redis;import org.springframework.cache.interceptor.KeyGenerator;import org.springframework.stereotype.Component;import java.lang.reflect.Method;import java.util.Arrays;@Componentpublic class MyKeyGenerator implements KeyGenerator { @Override public Object generate(Object target, Method method, Object..、params) { return target.toString() + ":" + method.getName() + ":" + Arrays.toString(params); }}

2）测试

2.3 .SpringCache更新缓存

1.使用@CachePut注解来更新，注意：@CachePut中的key要和@Cacheable中的key一样，否则更新不了！

2.4 .SpringCache清空缓存

1.使用@CacheEvict注解，主要key和要@Cacheable中的key一致

2.测试

2.5 .SpringCache其他用法

1.@Caching注解，可以组合多个注解

2.@CacheConfig注解

3.SpringCache用法（EhCache版）

1.pom.xml

<?xml version="1.0" encoding="UTF-8"?> 4.0.0 org.springframework.boot spring-boot-starter-parent 2.6.3 com.yl ehcache 0.0.1-SNAPSHOT ehcache Demo project for Spring Boot 11 org.springframework.boot spring-boot-starter-cache org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test net.sf.ehcache ehcache 2.10.6 org.springframework.boot spring-boot-maven-plugin

2.实体类

package com.yl.ehcache.model;import java.io.Serializable;public class User implements Serializable { private Integer id; private String username; private String password; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + ''' + ", password='" + password + ''' + '}'; }}

3.service

package com.yl.ehcache.service;import com.yl.ehcache.model.User;import org.springframework.cache.annotation.CacheEvict;import org.springframework.cache.annotation.Cacheable;import org.springframework.stereotype.Service;@Servicepublic class UserService { @Cacheable(cacheNames = "user") public User getUserById(Integer id) { System.out.println("getUserById()..."); User user = new User(); user.setId(id); user.setUsername("root"); user.setPassword("root"); return user; } @CacheEvict(cacheNames = "user") public void delete(Integer id) { System.out.println("delete"); }}

4.主程序

package com.yl.ehcache;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cache.annotation.EnableCaching;@SpringBootApplication@EnableCachingpublic class EhcacheApplication { public static void main(String[] args) { SpringApplication.run(EhcacheApplication.class, args); }}

5.ehcache.xml

6.测试