mybatius 缓存

最新推荐文章于 2023-12-03 21:28:57 发布

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最新推荐文章于 2023-12-03 21:28:57 发布

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分类专栏： mybatis

本文链接：https://blog.youkuaiyun.com/nt19931231/article/details/80046335

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本文详细介绍了如何在MyBatis中配置和使用二级缓存，包括实现序列化接口、设置缓存、编写接口和XML配置文件，以及进行测试验证。

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一  配置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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.xinxue.mybatius</groupId>
    <artifactId>mybatis_day3</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- 配置 mybatis 核心依赖 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <!--配置ehcache 做二级缓存的实现包-->
        <dependency>
            <groupId>org.mybatis.caches</groupId>
            <artifactId>mybatis-ehcache</artifactId>
            <version>1.1.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.44</version>
        </dependency>
        <!-- 导入log4j 日志包 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.21</version>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.xml</include>
                    <include>**/*.properties</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>
</project>

二、SqlSessionMapper

<?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>

    <environments default="d1">
        <environment id="d1">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql:///xingxue27"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>


    <mappers>
        <mapper resource="com/xingxue/mybatis/mapper/UserInfoModelMapper.xml"/>
    </mappers>
</configuration>

配置ehcache.xml

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">
	<diskStore path="d:/storeobject"/>
	<defaultCache
					maxElementsInMemory="10000" 
					eternal="false"      
					timeToIdleSeconds="120" 
					timeToLiveSeconds="120" 
					overflowToDisk="true"
					maxElementsOnDisk="10000000" 
					diskPersistent="false"
					diskExpiryThreadIntervalSeconds="120"
					memoryStoreEvictionPolicy="LRU" />
</ehcache>
<!-- <diskStore path="java.io.tmpdir" /> -->
<!-- <defaultCache
					maxElementsInMemory="10000"     设置了缓存的上限,最多存储多少个记录对象  10000个
					eternal="false"                 是否永久保存，如果设置为true
					timeToIdleSeconds="120"         空闲时间为120秒，过后对象清除
					timeToLiveSeconds="120"         最大的存活时间为120秒
					overflowToDisk="true"           如果内存缓存的对象超过10000，写硬盘上写
					maxElementsOnDisk="10000000"    硬盘上保存缓存对象数量
					diskPersistent="false"          硬盘保存的数据是否持久化
					diskExpiryThreadIntervalSeconds="120"
					memoryStoreEvictionPolicy="LRU" />  存储的算法 LRU 会回收不经常使用的数据 -->

配置日志

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

log4j.rootLogger=warn, stdout


log4j.logger.com.xingxue=debug

三，要实现二级缓存必须实现序列化接口Serializable

package com.xingxue.mybatis.model;

import java.io.Serializable;

// mybatis 的二级缓存数据，该数据类型必须实现 序列化接口Serializable
public class UserInfoModel implements Serializable {


    private Long userid;
    private String logname;
    private String password;

    public Long getUserid() {
        return userid;
    }

    public void setUserid(Long userid) {
        this.userid = userid;
    }

    public String getLogname() {
        return logname;
    }

    public void setLogname(String logname) {
        this.logname = logname;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "UserInfoModel{" +
                "userid=" + userid +
                ", logname='" + logname + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

四设置缓存

package com.xingxue.mybatis.util;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class SessionUtil {

    private static final SqlSessionFactory factory;


    static {
        try {
            factory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("SqlMapConfig.xml"));
        }catch (Exception e){
            throw new RuntimeException(e);
        }

    }
    /*二级缓存*/
    public  static SqlSessionFactory getFactory()
    {
        return factory;
    }

    /*一级缓存*/
    public static SqlSession getSession(){

        return factory.openSession();
    }
}

五写接口

package com.xingxue.mybatis.mapper;

import com.xingxue.mybatis.model.UserInfoModel;

public interface UserInfoModelMapper {


    UserInfoModel getById(Long id);


}

六写实现.xml 也就是写SQL

<?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.xingxue.mybatis.mapper.UserInfoModelMapper">

    <!--开启二级缓存-->
    <cache type="org.mybatis.caches.ehcache.EhcacheCache"/>

    <select id="getById" resultType="com.xingxue.mybatis.model.UserInfoModel">

        SELECT  * FROM TB_USERINFO WHERE USERID = #{ID}

    </select>

</mapper>

七测试

package com.xingxue.mybatis.test;


import com.xingxue.mybatis.mapper.UserInfoModelMapper;
import com.xingxue.mybatis.model.UserInfoModel;
import com.xingxue.mybatis.util.SessionUtil;
import org.apache.ibatis.session.SqlSession;

import java.io.IOException;

public class App {

    public static void main(String[] args) throws IOException {

        //一级缓存在作用  sqlSession 对象
        SqlSession session = SessionUtil.getSession();

        UserInfoModelMapper mapper = session.getMapper(UserInfoModelMapper.class);

        UserInfoModel user = mapper.getById(9L);

        System.out.println(user);

        session.close();

        System.out.println("=================================================");

        SqlSession session2 = SessionUtil.getSession();

         mapper = session2.getMapper(UserInfoModelMapper.class);

        UserInfoModel user2 = mapper.getById(9L);

        System.out.println(user2);


    }

}