第 20 講 SpringBoot整合Cache
阿新 • • 發佈：2018-12-20
第二十講 SpringBoot整合Cache
宣告式快取： Spring定義CacheManager和Cache介面用來統一不同的快取技術，例如：JCache,EhCache,Hazelcast,Guava,Redis等。在使用Spring整合Cache的時候，我們需要註冊實現CacheManager的Bean。Spring Boot為我們自動配置了JCacheCacheConfiguration,EhCacheCacheConfiguration,HazelcastCacheCnfiguration,GuavaCacheConfiguration、RedisCacheConfiguration、SimpleCacheConfiguration。
預設使用ConcurrenMapCacheManager
在我們不使用其他第三方快取依賴的時候，Spring自動採用ConcurrenMapCacheManager
2.1 SpringBoot整合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` 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 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匯入依賴
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
2.3 entity層：Account.java
public class Account {
private Integer id;
private String name;
private Double money;
......
}
2.4 dao層 ：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層：
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") /**開啟快取策略*/
public String queryBook(Integer num) {
simulateSlowService();
return num + "-- > Some Book";
}
/**
* @Description: 延時三秒
* @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 沒有開啟快取功能測試：
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: 沒有開啟快取，每隔三秒列印一次記錄
* @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 開啟快取測試
2.6.1 添加註解@EnableCaching
2.6.2 需要快取的方法添加註解@Cacheable
2.6.3 測試，當快取有這個資料時，會直接返回資料，不會等待資料庫去查詢資料
只有前面兩個資料，程式等待了3秒，之後的資料瞬間列印在了控制檯上，這說明快取起了作用。