二級緩存是多個SqlSession共享的,其做用域是mapper的同一個namespace,不一樣的sqlSession兩次執行相同namespace下的sql語句且向sql中傳遞參數也相同即最終執行相同的sql語句,第一次執行完畢會將數據庫中查詢的數據寫到緩存(內存),第二次會從緩存中獲取數據將再也不從數據庫查詢,從而提升查詢效率。Mybatis默認沒有開啓二級緩存須要在setting全局參數中配置開啓二級緩存。html
下面是使用Ehcache來做爲Mybatis二級緩存的實例:java
==mybatis.configuration.cache-enabled=true==mysql
默認二級緩存是開啓的git
server.port=80 # 數據源配置 spring.datasource.url=jdbc:mysql://localhost:3306/ssb_test spring.datasource.driver-class-name=com.mysql.jdbc.Driver spring.datasource.username=root spring.datasource.password=root #鏈接池配置 #spring.datasource.type=org.apache.commons.dbcp2.BasicDataSource #mybatis #entity掃描的包名 mybatis.type-aliases-package=com.xiaolyuh.domain.model #Mapper.xml所在的位置 mybatis.mapper-locations=classpath*:/mybaits/*Mapper.xml #開啓MyBatis的二級緩存 mybatis.configuration.cache-enabled=true #pagehelper pagehelper.helperDialect=mysql pagehelper.reasonable=true pagehelper.supportMethodsArguments=true pagehelper.params=count=countSql #日誌配置 logging.level.com.xiaolyuh=debug logging.level.org.springframework.web=debug logging.level.org.springframework.transaction=debug logging.level.org.mybatis=debug debug=false
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <artifactId>spring-boot-student-mybatis-ehcache</artifactId> <packaging>jar</packaging> <name>spring-boot-student-mybatis-ehcache</name> <description>Demo Mybatis ehcache for Spring Boot</description> <parent> <groupId>com.xiaolyuh</groupId> <artifactId>spring-boot-student</artifactId> <version>0.0.1-SNAPSHOT</version> <relativePath /> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.0</version> </dependency> <!--pagehelper --> <dependency> <groupId>com.github.pagehelper</groupId> <artifactId>pagehelper-spring-boot-starter</artifactId> <version>1.1.1</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.31</version> </dependency> <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache</artifactId> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-ehcache</artifactId> <version>1.0.0</version> </dependency> </dependencies> </project>
在src\main\resources目錄下建立ehcache.xml文件,內容以下:github
<?xml version="1.0" encoding="UTF-8"?> <ehcache> <!-- http://www.cnblogs.com/lzy1991/p/5335249.html http://www.cnblogs.com/little-fly/p/6251439.html 緩存配置 diskStore:指定數據在磁盤中的存儲位置。 name:緩存名稱。 defaultCache:當藉助CacheManager.add("demoCache")建立Cache時,EhCache便會採用<defalutCache/>指定的的管理策略,如下屬性是必須的: maxElementsInMemory:緩存最大個數。 eternal:對象是否永久有效,一但設置了,timeout將不起做用。 timeToIdleSeconds:設置對象在失效前的容許閒置時間(單位:秒)。僅當eternal=false對象不是永久有效時使用,可選屬性,默認值是0,也就是可閒置時間無窮大。 timeToLiveSeconds:設置對象在失效前容許存活時間(單位:秒)。最大時間介於建立時間和失效時間之間。僅當eternal=false對象不是永久有效時使用,默認是0.,也就是對象存活時間無窮大。 overflowToDisk:當內存中對象數量達到maxElementsInMemory時,Ehcache將會對象寫到磁盤中。 diskSpoolBufferSizeMB:這個參數設置DiskStore(磁盤緩存)的緩存區大小。默認是30MB。每一個Cache都應該有本身的一個緩衝區。 maxElementsOnDisk:硬盤最大緩存個數。 diskPersistent:是否緩存虛擬機重啓期數據 Whether the disk store persists between restarts of the Virtual Machine. The default value is false. diskExpiryThreadIntervalSeconds:磁盤失效線程運行時間間隔,默認是120秒。 memoryStoreEvictionPolicy:當達到maxElementsInMemory限制時,Ehcache將會根據指定的策略去清理內存。默認策略是LRU(最近最少使用)。你能夠設置爲FIFO(先進先出)或是LFU(較少使用)。 clearOnFlush:內存數量最大時是否清除。 --> <diskStore path="e:\ehcache" /> <defaultCache maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="120" timeToLiveSeconds="120" overflowToDisk="true" maxElementsOnDisk="10000000" diskPersistent="false" diskExpiryThreadIntervalSeconds="120" memoryStoreEvictionPolicy="LRU" /> </ehcache>
<cache /> 添加這個節點會默認將該namespace下全部的的select語句緩存。若是不須要進行緩存,須要設置useCache="false"。web
<select id="findByPage" resultMap="BaseResultMap" useCache="false">
完整的Mapper文件,以下:spring
<?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.xiaolyuh.domain.mapper.PersonMapper"> <!--mybatis ehcache緩存配置 --> <!-- 如下兩個<cache>標籤二選一,第一個能夠輸出日誌,第二個不輸出日誌 --> <!--<cache type="org.mybatis.caches.ehcache.LoggingEhcache" /> <cache type="org.mybatis.caches.ehcache.EhcacheCache"/>--> <!--根據需求調整緩存參數:--> <cache type="org.mybatis.caches.ehcache.EhcacheCache"> <property name="timeToIdleSeconds" value="3600"/> <property name="timeToLiveSeconds" value="3600"/> <!-- 同ehcache參數maxElementsInMemory --> <property name="maxEntriesLocalHeap" value="1000"/> <!-- 同ehcache參數maxElementsOnDisk --> <property name="maxEntriesLocalDisk" value="10000000"/> <property name="memoryStoreEvictionPolicy" value="LRU"/> </cache> <resultMap id="BaseResultMap" type="com.xiaolyuh.domain.model.Person"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> <id column="id" property="id" jdbcType="BIGINT"/> <result column="name" property="name" jdbcType="VARCHAR"/> <result column="age" property="age" jdbcType="INTEGER"/> <result column="address" property="address" jdbcType="VARCHAR"/> </resultMap> <sql id="Base_Column_List"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> id, name, age, address </sql> <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Long"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> select <include refid="Base_Column_List"/> from person where id = #{id,jdbcType=BIGINT} </select> <delete id="deleteByPrimaryKey" parameterType="java.lang.Long"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> delete from person where id = #{id,jdbcType=BIGINT} </delete> <insert id="insert" parameterType="com.xiaolyuh.domain.model.Person"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> <selectKey resultType="java.lang.Long" keyProperty="id" order="AFTER"> SELECT LAST_INSERT_ID() </selectKey> insert into person (name, age, address ) values (#{name,jdbcType=VARCHAR}, #{age,jdbcType=INTEGER}, #{address,jdbcType=VARCHAR} ) </insert> <insert id="insertSelective" parameterType="com.xiaolyuh.domain.model.Person"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> <selectKey resultType="java.lang.Long" keyProperty="id" order="AFTER"> SELECT LAST_INSERT_ID() </selectKey> insert into person <trim prefix="(" suffix=")" suffixOverrides=","> <if test="name != null"> name, </if> <if test="age != null"> age, </if> <if test="address != null"> address, </if> </trim> <trim prefix="values (" suffix=")" suffixOverrides=","> <if test="name != null"> #{name,jdbcType=VARCHAR}, </if> <if test="age != null"> #{age,jdbcType=INTEGER}, </if> <if test="address != null"> #{address,jdbcType=VARCHAR}, </if> </trim> </insert> <update id="updateByPrimaryKeySelective" parameterType="com.xiaolyuh.domain.model.Person"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> update person <set> <if test="name != null"> name = #{name,jdbcType=VARCHAR}, </if> <if test="age != null"> age = #{age,jdbcType=INTEGER}, </if> <if test="address != null"> address = #{address,jdbcType=VARCHAR}, </if> </set> where id = #{id,jdbcType=BIGINT} </update> <update id="updateByPrimaryKey" parameterType="com.xiaolyuh.domain.model.Person"> <!-- WARNING - @mbggenerated This element is automatically generated by MyBatis Generator, do not modify. --> update person set name = #{name,jdbcType=VARCHAR}, age = #{age,jdbcType=INTEGER}, address = #{address,jdbcType=VARCHAR} where id = #{id,jdbcType=BIGINT} </update> <!-- 對這個語句useCache="true"默認是true,能夠不寫 --> <select id="findAll" resultMap="BaseResultMap" useCache="true"> select <include refid="Base_Column_List"/> from person </select> <!-- 對這個語句禁用二級緩存 --> <select id="findByPage" resultMap="BaseResultMap" useCache="false"> select <include refid="Base_Column_List"/> from person </select> </mapper>
package com.xiaolyuh.domain.model; import java.io.Serializable; public class Person implements Serializable { private Long id; /** * 名稱 */ private String name; /** * 年齡 */ private Integer age; /** * 地址 */ private String address; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } }
package com.xiaolyuh.domain.mapper; import com.github.pagehelper.Page; import com.xiaolyuh.domain.model.Person; import org.apache.ibatis.annotations.Mapper; import java.util.List; @Mapper//聲明成mybatis Dao層的Bean,也能夠在配置類上使用@MapperScan("com.xiaolyuh.domain.mapper")註解聲明 public interface PersonMapper { int deleteByPrimaryKey(Long id); int insert(Person record); int insertSelective(Person record); Person selectByPrimaryKey(Long id); int updateByPrimaryKeySelective(Person record); int updateByPrimaryKey(Person record); /** * 獲取全部數據 * @return */ List<Person> findAll(); /** * 分頁查詢數據 * @return */ Page<Person> findByPage(); }
package com.xiaolyuh.service; import com.github.pagehelper.Page; import com.xiaolyuh.domain.model.Person; import java.util.List; /** * Created by yuhao.wang on 2017/6/19. */ public interface PersonService { List<Person> findAll(); /** * 分頁查詢 * @param pageNo 頁號 * @param pageSize 每頁顯示記錄數 * @return */ Page<Person> findByPage(int pageNo, int pageSize); void insert(Person person); }
package com.xiaolyuh.service.impl; import com.github.pagehelper.Page; import com.github.pagehelper.PageHelper; import com.xiaolyuh.domain.mapper.PersonMapper; import com.xiaolyuh.domain.model.Person; import com.xiaolyuh.service.PersonService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import java.util.List; /** * Created by yuhao.wang on 2017/6/19. */ @Service @Transactional(readOnly = true) public class PersonServiceImpl implements PersonService { @Autowired private PersonMapper personMapper; @Override public List<Person> findAll() { return personMapper.findAll(); } @Override public Page<Person> findByPage(int pageNo, int pageSize) { PageHelper.startPage(pageNo, pageSize); return personMapper.findByPage(); } @Override @Transactional public void insert(Person person) { personMapper.insert(person); } }
package com.xiaolyuh; import com.github.pagehelper.Page; import com.xiaolyuh.domain.model.Person; import com.xiaolyuh.service.PersonService; import org.junit.Assert; import org.junit.Before; import org.junit.Test; import org.junit.runner.RunWith; import com.alibaba.fastjson.JSON; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringRunner; import java.util.List; @RunWith(SpringRunner.class) @SpringBootTest public class PersonMapperTests { private Logger logger = LoggerFactory.getLogger(PersonMapperTests.class); @Autowired private PersonService personService; @Before public void testInsert() { Person person = new Person(); person.setName("測試"); person.setAddress("address"); person.setAge(10); personService.insert(person); Assert.assertNotNull(person.getId()); logger.debug(JSON.toJSONString(person)); } @Test public void testFindAll() { List<Person> persons = personService.findAll(); Assert.assertNotNull(persons); logger.debug(JSON.toJSONString(persons)); } @Test public void testFindByPage() { Page<Person> persons = personService.findByPage(1, 2); Assert.assertNotNull(persons); logger.debug(persons.toString()); logger.debug(JSON.toJSONString(persons)); } @Test public void testCacheByPage() { long begin = System.currentTimeMillis(); List<Person> persons = personService.findAll(); long ing = System.currentTimeMillis(); personService.findAll(); long end = System.currentTimeMillis(); logger.debug("第一次請求時間:" + (ing - begin) + "ms"); logger.debug("第二次請求時間:" + (end - ing) + "ms"); Assert.assertNotNull(persons); logger.debug(persons.toString()); logger.debug(JSON.toJSONString(persons)); } }
Cache Hit Ratio [com.xiaolyuh.domain.mapper.PersonMapper]: 0.5 2017-06-28 10:15:32.214 DEBUG 10472 --- [ main] org.mybatis.spring.SqlSessionUtils : Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@3f6c2763] 2017-06-28 10:15:32.214 DEBUG 10472 --- [ main] org.mybatis.spring.SqlSessionUtils : Transaction synchronization committing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@3f6c2763] 2017-06-28 10:15:32.214 DEBUG 10472 --- [ main] org.mybatis.spring.SqlSessionUtils : Transaction synchronization deregistering SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@3f6c2763] 2017-06-28 10:15:32.214 DEBUG 10472 --- [ main] org.mybatis.spring.SqlSessionUtils : Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@3f6c2763] 2017-06-28 10:15:32.223 DEBUG 10472 --- [ main] com.xiaolyuh.PersonMapperTests : 第一次請求時間:26ms 2017-06-28 10:15:32.223 DEBUG 10472 --- [ main] com.xiaolyuh.PersonMapperTests : 第二次請求時間:11ms
https://github.com/wyh-spring-ecosystem-student/spring-boot-student/tree/releasessql
spring-boot-student-mybatis-ehcache工程數據庫