SpringBoot与SpringCache
#Hideonbush 人气:01.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"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.6.3</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.yl</groupId> <artifactId>cache_redis</artifactId> <version>0.0.1-SNAPSHOT</version> <name>cache_redis</name> <description>Demo project for Spring Boot</description> <properties> <java.version>11</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <artifactId>spring-boot-starter-data-redis</artifactId> <artifactId>spring-boot-starter-web</artifactId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
2.application.properties
# redis的配置 spring.redis.host=192.168.244.135 spring.redis.port=6379 spring.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; @Service public 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; @Component public 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"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.6.3</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.yl</groupId> <artifactId>ehcache</artifactId> <version>0.0.1-SNAPSHOT</version> <name>ehcache</name> <description>Demo project for Spring Boot</description> <properties> <java.version>11</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <artifactId>spring-boot-starter-web</artifactId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache</artifactId> <version>2.10.6</version> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
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; @Service public 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 @EnableCaching public class EhcacheApplication { public static void main(String[] args) { SpringApplication.run(EhcacheApplication.class, args); } }
5.ehcache.xml
<ehcache> <diskStore path="java.io.tmpdir/shiro-spring-sample"/> <defaultCache maxElementsInMemory = "1000" eternal = "false" timeToIdleSeconds = "120" timeToLiveSeconds = "120" overflowToDisk = "false" diskPersistent = "false" diskExpiryThreadIntervalSeconds = "120"/> <cache name = "user" maxElementsInMemory = "1000" eternal = "false" overflowToDisk = "true" diskPersistent = "true" diskExpiryThreadIntervalSeconds = "600"/> </ehcache>
6.测试
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