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第二十讲 SpringBoot集成Cache
文章目录
声明式缓存：
Spring定义CacheManager和Cache接口用来统一不同的缓存技术，例如：JCache,EhCache,Hazelcast,Guava,Redis等。在使用Spring集成Cache的时候，我们需要注册实现CacheManager的Bean。
Spring Boot为我们自动配置了JCacheCacheConfiguration,EhCacheCacheConfiguration,HazelcastCacheCnfiguration,GuavaCacheConfiguration、RedisCacheConfiguration、SimpleCacheConfiguration。
默认使用ConcurrenMapCacheManager
在我们不使用其他第三方缓存依赖的时候，Spring自动采用ConcurrenMapCacheManager
2.1 SpringBoot集成mybatis
create table `account` (
`id` int (11),
`name` varchar (60),
`money` double
);
insert into `account` (`id`, `name`, `money`) values('1','李四','1');
insert into `account` (`id`, `name`, `money`) values('2','王老五','5.6');
insert into `account` (`id`, `name`, `money`) values('3','张三','4');
application.yml
spring:
datasource:
driver-class-name : com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/ssm
username: root
password: root
mybatis:
type-aliases-package: com.springboot.cache
mapper-locations: classpath:mybatis/mapper/*.xml
config-location: classpath:mybatis/config/mybatis-config.xml
mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<typeAliases>
</typeAliases>
</configuration>
2.2 pom.xml导入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
2.3 entity层：Account.java
public class Account {
private Integer id;
private String name;
private Double money;
......
}
2.4 dao层 ：AccountDao.java
package com.springboot.cache.dao;
import com.springboot.cache.entity.Account;
import org.springframework.stereotype.Repository;
import java.util.List;
/**
* @Description:
* @CreateTime: 2018-10-17 21:11
* @Version:v1.0
*/
@Repository
public interface AccountDao {
List<Account> queryAll();
Account queryAccountById(Integer id);
}
AccountMapper.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.springboot.cache.dao.AccountDao">
<resultMap id="BaseResultMap" type="com.springboot.cache.entity.Account">
<id column="id" property="id" jdbcType="INTEGER"/>
<result column="name" property="name" jdbcType="VARCHAR"/>
<result column="money" property="money" jdbcType="DOUBLE"/>
</resultMap>
<sql id="Base_Column_List">
id,name,money
</sql>
<select id="queryAccountById" resultMap="BaseResultMap">
SELECT
<include refid="Base_Column_List"/>
FROM account
WHERE id = #{id,jdbcType=INTEGER}
</select>
<select id="queryAll" resultMap="BaseResultMap">
SELECT
<include refid="Base_Column_List"/>
FROM account
</select>
</mapper>
2.5 service层：
IAccountService.java
package com.springboot.cache.service;
import com.springboot.cache.entity.Account;
import java.util.List;
/**
* @Description:
* @CreateTime: 2018-10-17 21:29
* @Version:v1.0
*/
public interface IAccoutService {
List<Account> queryAll();
Account queryAccountById(Integer id);
String queryBook(Integer num);
}
AccountServiceImpl.java
package com.springboot.cache.service.impl;
import com.springboot.cache.dao.AccountDao;
import com.springboot.cache.entity.Account;
import com.springboot.cache.service.IAccoutService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
import java.util.List;
/**
* @Description:
* @Author: zrblog
* @CreateTime: 2018-10-17 21:30
* @Version:v1.0
*/
@Service
public class AccountService implements IAccoutService {
@Autowired
private AccountDao accountDao;
@Override
public List<Account> queryAll() {
return accountDao.queryAll();
}
@Override
@Cacheable("queryAccountById")
public Account queryAccountById(Integer id) {
simulateSlowService();
return accountDao.queryAccountById(id);
}
@Override
@Cacheable("books") /**开启缓存策略*/
public String queryBook(Integer num) {
simulateSlowService();
return num + "-- > Some Book";
}
/**
* @Description: 延时三秒
* @Date: 2018/10/18 22:32
* @Author: zr
* @param null
* @Return
*/
private void simulateSlowService() {
try {
long time = 3000L;
Thread.sleep(time);
} catch (InterruptedException e) {
throw new IllegalStateException(e);
}
}
}
2.5 没有开启缓存功能测试：
package com.springboot.cache;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.springboot.cache.entity.Account;
import com.springboot.cache.service.impl.AccountService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.List;
@RunWith(SpringRunner.class)
@SpringBootTest
@MapperScan(value = "com.springboot.cache.dao")
public class ApplicationTests {
@Autowired
private AccountService accountService;
@Test
public void contextLoads() {
}
@Test
public void testMybatis() throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
List<Account> accounts = accountService.queryAll();
System.out.println("result:"+mapper.writeValueAsString(accounts));
}
/**
* @Description: 没有开启缓存，每隔三秒打印一次记录
* @Date: 2018/10/17
* @Author: zr
* @param null
* @Return
*/
@Test
public void testCache() throws JsonProcessingException {
printlnAccount(1);
printlnAccount(2);
printlnAccount(1);
printlnAccount(1);
printlnAccount(2);
}
private void printlnAccount(Integer id) throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
Account account = accountService.queryAccountById(id);
String accountJson = mapper.writeValueAsString(account);
System.out.println("Account--" +id+ "-->" + accountJson);
}
2.6 开启缓存测试
2.6.1 添加注解@EnableCaching
2.6.2 需要缓存的方法添加注解@Cacheable
2.6.3 测试，当缓存有这个数据时，会直接返回数据，不会等待数据库去查询数据
只有前面两个数据，程序等待了3秒，之后的数据瞬间打印在了控制台上，这说明缓存起了作用。