Mybatis學習記錄--延遲加載Lazyloading 和緩存機制ehcache

1， 聲明

本部落格所有内容來源于網絡、書籍、和各類手冊。

内容均為非盈利，旨為學習記錄，友善查詢、總結備份、開源分享。

部分轉載内容均有注明出處，如有侵權請告知，馬上删除.

2，參考連結

Mybatis(五) 延遲加載和緩存機制(一級二級緩存)

MyBatis-23MyBatis緩存配置【二級緩存】

Windows 啟動 Idea 報錯 if you already hava a 64-bit JDK…以及 failed to create jvm…

3， maven依賴管理

添加日志管理報log4j 和slf4j，橋接jar包slf4j-log4j12

<?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.hardes</groupId>
  <artifactId>MybatisEntry7_LazyLoad</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>MybatisEntry7_LazyLoad</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
    <!-- spring版本号 -->
    <spring.version>5.1.9.RELEASE</spring.version>
    <!-- Mybatis版本号 -->
    <mybatis.version>3.4.6</mybatis.version>
    <!-- log4j 版本号 -->
    <log4j.version>1.2.17</log4j.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <!-- spring核心包 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-oxm</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!-- 導入dbcp的jar包，用來在applicationContext.xml中配置資料庫 -->
    <dependency>
      <groupId>commons-dbcp</groupId>
      <artifactId>commons-dbcp</artifactId>
      <version>1.4</version>
    </dependency>
    <!-- mybatis核心包 -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>
    <!-- mybatis/spring包 -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.2</version>
    </dependency>

    <!-- 導入Mysql資料庫連結jar包 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.16</version>
    </dependency>

    <!-- 日志檔案管理包 -->
    <!-- log start -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>${log4j.version}</version>
    </dependency>

    <!-- slf4j日志包-->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.25</version>
    </dependency>
    <!-- slf4j+ log4j橋接 日志包-->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.25</version>
      <scope>test</scope>
    </dependency>


    <!-- 緩存架構(ehcache) -->
    <dependency>
      <groupId>net.sf.ehcache</groupId>
      <artifactId>ehcache-core</artifactId>
      <version>2.6.11</version>
    </dependency>

    <!-- 緩存架構(mybatis整合ehcache)-->
    <dependency>
      <groupId>org.mybatis.caches</groupId>
      <artifactId>mybatis-ehcache</artifactId>
      <version>1.1.0</version>
    </dependency>

  </dependencies>

  <build>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
        <plugin>
          <artifactId>maven-site-plugin</artifactId>
          <version>3.7.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
      </plugins>
    </pluginManagement>
    <resources>
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.xml</include>
        </includes>
      </resource>
    </resources>
  </build>
</project>


           

4, 工具

Idea 2019.2

maven 3.61

mysql 8.017

mybatis

Navicat

5，代碼結構

6， Mybatis Generator 配置檔案

SqlMapConfig.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>

    <settings>
        <!-- 用于輸出日志 log4j:LOG4J SLF4J -->
        <setting name="logImpl" value="SLF4J"/>
        <!--打開延遲加載的開關，預設為true-->
        <setting name="lazyLoadingEnabled" value="true"/>
        <!--積極的懶加載，預設是true，設定為false時，懶加載生效-->
        <setting name="aggressiveLazyLoading" value="false"/>
        <!--開啟二級緩存總開關-->
        <setting name="cacheEnabled" value="true"/>
    </settings>

    <typeAliases>
        <!-- 别名為類名首字母大小寫都可以 -->
        <package name="com.hardes.pojos"/>
    </typeAliases>


    <!-- 原先這裡還有連接配接資料庫的一些配置，與spring整合後，都交由spring來管理 -->
    <!-- 加載mapper映射檔案,使用通用的配置 -->
    <mappers>
        <package name="com.hardes.mappers"/>
    </mappers>

</configuration>
           

7， ehcache.xml

放置在resource 路徑下面

<?xml version="1.0" encoding="UTF-8"?>
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">
    <!-- 緩存資料要存放的磁盤位址 -->
    <diskStore path="D:\CM_Library\java\maven\ehcache" />
    <!-- diskStore：指定資料在磁盤中的存儲位置。  defaultCache：當借助CacheManager.add("demoCache")建立Cache時，EhCache便會采用<defalutCache/>指定的的管理政策
        以下屬性是必須的：  maxElementsInMemory - 在記憶體中緩存的element的最大數目  maxElementsOnDisk
        - 在磁盤上緩存的element的最大數目，若是0表示無窮大  eternal - 設定緩存的elements是否永遠不過期。如果為true，則緩存的資料始終有效，如果為false那麼還要根據timeToIdleSeconds，timeToLiveSeconds判斷
         overflowToDisk - 設定當記憶體緩存溢出的時候是否将過期的element緩存到磁盤上 以下屬性是可選的：  timeToIdleSeconds
        - 當緩存在EhCache中的資料前後兩次通路的時間超過timeToIdleSeconds的屬性取值時，這些資料便會删除，預設值是0,也就是可閑置時間無窮大
         timeToLiveSeconds - 緩存element的有效生命期，預設是0.,也就是element存活時間無窮大 diskSpoolBufferSizeMB
        這個參數設定DiskStore(磁盤緩存)的緩存區大小.預設是30MB.每個Cache都應該有自己的一個緩沖區.  diskPersistent
        - 在VM重新開機的時候是否啟用磁盤儲存EhCache中的資料，預設是false。  diskExpiryThreadIntervalSeconds
        - 磁盤緩存的清理線程運作間隔，預設是120秒。每個120s，相應的線程會進行一次EhCache中資料的清理工作  memoryStoreEvictionPolicy
        - 當記憶體緩存達到最大，有新的element加入的時候， 移除緩存中element的政策。預設是LRU（最近最少使用），可選的有LFU（最不常使用）和FIFO（先進先出） -->

    <!--defaultCache元素将僅在以程式設計方式建立緩存而未指定配置時使用-->
    <defaultCache maxElementsInMemory="1000"
                  maxElementsOnDisk="10000000" eternal="false" overflowToDisk="true"
                  timeToIdleSeconds="120" timeToLiveSeconds="120"
                  diskExpiryThreadIntervalSeconds="120" memoryStoreEvictionPolicy="LRU">
    </defaultCache>
    <!--  定義alldatas緩存
    <cache name="alldatas" maxEntriesLocalHeap="1000" eternal="false"
           timeToIdleSeconds="21600" timeToLiveSeconds="21600" memoryStoreEvictionPolicy="LRU"
           overflowToDisk="true"
           diskPersistent="false"
           diskExpiryThreadIntervalSeconds="120">

    </cache>
    -->

</ehcache>
           

8， Spring配置檔案

applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd ">
    <!-- 引用java配置檔案 -->
    <context:property-placeholder location="classpath:jdbc.properties"/>


    <!-- 配置資料源 -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="${db.driver}"/>
        <property name="url" value="${db.url}"/>
        <property name="username" value="${db.username}"/>
        <property name="password" value="${db.password}"/>
        <property name="maxActive" value="10"/>
        <property name="maxIdle" value="5"/>
    </bean>

    <!-- 配置SqlSessionFactory -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 指定mybatis的全局配置檔案的路徑 -->
        <property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"></property>
        <!-- 資料源 -->
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!-- 批量配置，這裡是批量配置mapper代理，那麼下面就不用配置id了。
       我們想要擷取哪個mapper代理用這個格式：類名首字母小寫
    -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.hardes.mappers"></property>
        <!-- 預設不需要配置，但是如果有多個資料源的配置，那麼就需要配置此項 -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

</beans>
           

9, properties

jdbc.properties

db.driver=com.mysql.cj.jdbc.Driver
db.url=jdbc:mysql:///test?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC
db.username=root
db.password=root
           

log4j.properties

# Global logging configuration
# 在開發環境下日志級别建議設定為DEBUG，生産環境設定成INFO或ERROR
log4j.rootLogger=DEBUG, stdout
# Console output
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPat
           

10, mappers

OrdersMapper.java

package com.hardes.mappers;

import com.hardes.pojos.Orders;
import com.hardes.pojos.OrdersExt;
import com.hardes.pojos.Users;

import java.util.List;

public interface OrdersMapper {

    List<OrdersExt> findOrdersAndUsersByOid1(int i);
    List<Orders> findOrdersAndUserLazyloading();

}

           

OrdersMapper.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">
<!--
    namespace命名空間，作用就是對sql進行分類化管理，将sql隔離
    注意：使用mapper代理方法開發，namespace有特殊重要的作用，namespace為對應的mapper接口位址
-->
<mapper namespace="com.hardes.mappers.OrdersMapper">
    <!--開啟二級緩存你，預設使用PerpetualCache-->
    <cache type="org.mybatis.caches.ehcache.EhcacheCache"/>

    <!--一對一映射,還用resultType-->
    <select id="findOrdersAndUsersByOid1" parameterType="int" resultType="com.hardes.pojos.OrdersExt">
        SELECT *

        FROM users,orders WHERE  orders.id=#{oid} AND orders.user_id= users.id
    </select>



   <resultMap id="OrdersAndUserLazyloading" type="com.hardes.pojos.Orders">
       <id column="orders_id"  property="oid"/>
       <result column="number" property="number"/>
       <result  column="user_id" property="user_id"/>
       <!-- users為Orders類中的屬性-->
       <association property="users"
                    column="user_id"
                    select="com.hardes.mappers.UsersMapper.findUserById"/>
   </resultMap>

    <select id="findOrdersAndUserLazyloading" resultMap="OrdersAndUserLazyloading" useCache="true" flushCache="false">
        SELECT
        orders.id orders_id,
        orders.number,
        orders.user_id,
        orders.*

        FROM orders
    </select>


</mapper>
           

UsersMapper.java

package com.hardes.mappers;

import com.hardes.pojos.Users;

import java.util.List;

public interface UsersMapper {

    List<Users> findOrdersAndUsersByOid2(int id);
    List<Users>   findUserById(int i);
}


           

UsersMapper.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">
<!--
    namespace命名空間，作用就是對sql進行分類化管理，将sql隔離
    注意：使用mapper代理方法開發，namespace有特殊重要的作用，namespace為對應的mapper接口位址
-->
<mapper namespace="com.hardes.mappers.UsersMapper">
    <!--開啟二級緩存你，預設使用PerpetualCache-->
     <cache type="org.mybatis.caches.ehcache.EhcacheCache"/>

    <resultMap id="findOrdersAndUsersReM" type="com.hardes.pojos.Users">
        <id column="uid" property="id"/>
        <result column="username" property="username"/>
        <result column="sex" property="sex"/>

        <!-- orders為Users類中的屬性-->
        <association property="orders" javaType="com.hardes.pojos.Orders">
            <id column="oid" property="id"/>
            <result column="number" property="number"/>
            <result column="user_id" property="userId"/>
            <result column="time"   property="time"/>
        </association>
    </resultMap>

    <select id="findOrdersAndUsersByOid2" parameterType="int" resultMap="findOrdersAndUsersReM">
        SELECT
            users.id uid,
            users.username,
            users.sex,
            orders.id oid,
            orders.number,
            orders.user_id,
            orders.time

         FROM users,orders WHERE  users.id=#{id} AND users.id=orders.user_id
    </select>

<!--lazy loading-->
    <select id="findUserById"   parameterType="int" resultType="com.hardes.pojos.Users"  useCache="true" flushCache="false">
        SELECT *
        FROM    users
        WHERE id=#{id}
    </select>



</mapper>
           

11， pojos類

Items.java

package com.hardes.pojos;

import java.util.Date;

public class Items {
    private Integer id;
    private String name;
    private String detail;
    private Float price;
    private String pic;
    private Date time;

    //訂單項集合
    //private List<Orders_detail> orders_detailList;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDetail() {
        return detail;
    }

    public void setDetail(String detail) {
        this.detail = detail;
    }

    public Float getPrice() {
        return price;
    }

    public void setPrice(Float price) {
        this.price = price;
    }

    public String getPic() {
        return pic;
    }

    public void setPic(String pic) {
        this.pic = pic;
    }

    public Date getTime() {
        return time;
    }

    public void setTime(Date time) {
        this.time = time;
    }
}

           

Orders.java

package com.hardes.pojos;

import java.io.Serializable;
import java.util.Date;


public class Orders implements Serializable {
    private Integer oid;
    private Integer user_id;
    private String number;
    private Date time;
    private String note;
    private Users users;
    
    //訂單明細集合
   // private List<Orders_detail> detailList;


    public Integer getOid() {
        return oid;
    }

    public void setOid(Integer oid) {
        this.oid = oid;
    }

    public Integer getUser_id() {
        return user_id;
    }

    public void setUser_id(Integer user_id) {
        this.user_id = user_id;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public Date getTime() {
        return time;
    }

    public void setTime(Date time) {
        this.time = time;
    }

    public String getNote() {
        return note;
    }

    public void setNote(String note) {
        this.note = note;
    }

    public Users getUsers() {
        return users;
    }

    public void setUsers(Users users) {
        this.users = users;
    }

    @Override
    public String toString() {
        return "Orders{" +
                "oid=" + oid +
                ", user_id=" + user_id +
                ", number='" + number + '\'' +
                ", time=" + time +
                ", note='" + note + '\'' +
                ", users=" + users +
                '}';
    }
}

           

Orders_detail.java

package com.hardes.pojos;

public class Orders_detail {
    private Integer id;
    private Integer ordersId;
    private Integer itemsId;
    private Integer itemsNum;
    //商品資訊
   //private Items items;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getOrdersId() {
        return ordersId;
    }

    public void setOrdersId(Integer ordersId) {
        this.ordersId = ordersId;
    }

    public Integer getItemsId() {
        return itemsId;
    }

    public void setItemsId(Integer itemsId) {
        this.itemsId = itemsId;
    }

    public Integer getItemsNum() {
        return itemsNum;
    }

    public void setItemsNum(Integer itemsNum) {
        this.itemsNum = itemsNum;
    }

    @Override
    public String toString() {
        return "Orders_detail{" +
                "id=" + id +
                ", ordersId=" + ordersId +
                ", itemsId=" + itemsId +
                ", itemsNum=" + itemsNum +
                '}';
    }
}

           

OrdersExt.java

package com.hardes.pojos;


import java.io.Serializable;
import java.util.Date;

public class OrdersExt extends Orders implements Serializable {
    private String username;
    private Date birthday;
    private char sex;
    private String address;



    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public char getSex() {
        return sex;
    }

    public void setSex(char sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "OrdersExt{" +
                "username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex=" + sex +
                ", address='" + address + '\'' +
                ", "+super.toString()+

                '}';
    }
}

           

Users.java

package com.hardes.pojos;

import java.io.Serializable;
import java.util.Date;

public class Users implements Serializable {
    private int id;
    private String username;
    private String sex;
    private Date birthday;
    private String address;
    //private Orders orders;
    //訂單資訊集合
   // private List<Orders> ordersList;



    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Users{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                ", address='" + address + '\'' +
                '}';
    }
}

           

12, 測試檔案

package com.hardes;

import com.hardes.mappers.OrdersMapper;
import com.hardes.pojos.Orders;
import com.hardes.pojos.OrdersExt;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

public class TestUsers1 {
    @Test
    public void userTest1(){
        ApplicationContext ac = new ClassPathXmlApplicationContext("spring/applicationContext.xml");
        /**
         * 使用resultType作映射,查詢訂單orders 并關聯users的資訊
         */
        OrdersMapper ordersmapper= (OrdersMapper) ac.getBean("ordersMapper");

        List<OrdersExt> list = ordersmapper.findOrdersAndUsersByOid1(2);

        System.out.println(list);

        //隻查詢了一次sql，是以第二次通路是從ehcache緩存中拿的

        List<OrdersExt> list3 = ordersmapper.findOrdersAndUsersByOid1(2);

        System.out.println(list3);


        /**
         * 使用resultType作映射,lazy loading
         */
        List<Orders> list1 = ordersmapper.findOrdersAndUserLazyloading();

        System.out.println(list1);
         //隻查詢了一次sql，是以第二次通路是從ehcache緩存中拿的
        List<Orders> list2 = ordersmapper.findOrdersAndUserLazyloading();

        System.out.println(list2);

    }

}
           

Note

測試檔案中的第一個是對resultMap作為映射的相關聯查詢，同時增加了list3作為檢驗ehcache架構的測試

OrdersMapper ordersmapper= (OrdersMapper) ac.getBean("ordersMapper");

        List<OrdersExt> list = ordersmapper.findOrdersAndUsersByOid1(2);

        System.out.println(list);

        //隻查詢了一次sql，是以第二次通路是從ehcache緩存中拿的

        List<OrdersExt> list3 = ordersmapper.findOrdersAndUsersByOid1(2);

        System.out.println(list3);
           

第二個測試項目才是延遲加載和緩存機制的測試，增加list2作為ehcache架構的測試

/**
         * 使用resultType作映射,lazy loading
         */
        List<Orders> list1 = ordersmapper.findOrdersAndUserLazyloading();

        System.out.println(list1);
         //隻查詢了一次sql，是以第二次通路是從ehcache緩存中拿的
        List<Orders> list2 = ordersmapper.findOrdersAndUserLazyloading();

        System.out.println(list2);
           

13， 測試結果

DEBUG [main] - JDBC Connection [jdbc:mysql:///test?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC, UserName=[email protected], MySQL Connector/J] will not be managed by Spring
DEBUG [main] - ==>  Preparing: SELECT * FROM users,orders WHERE orders.id=? AND orders.user_id= users.id 
DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <==      Total: 1
DEBUG [main] - put added 0 on heap
DEBUG [main] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@35038141]
[OrdersExt{username='Tom', birthday=Sun Oct 06 08:00:00 SGT 2019, sex=M, address='Jurong East', Orders{oid=null, user_id=1, number='2000', time=Mon Oct 07 21:47:26 SGT 2019, note='bread', users=null}}]
DEBUG [main] - Creating a new SqlSession
DEBUG [main] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c12f3ee] was not registered for synchronization because synchronization is not active
DEBUG [main] - Cache Hit Ratio [com.hardes.mappers.OrdersMapper]: 0.5
DEBUG [main] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1c12f3ee]
[OrdersExt{username='Tom', birthday=Sun Oct 06 08:00:00 SGT 2019, sex=M, address='Jurong East', Orders{oid=null, user_id=1, number='2000', time=Mon Oct 07 21:47:26 SGT 2019, note='bread', users=null}}]
DEBUG [main] - Creating a new SqlSession
DEBUG [main] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6d467c87] was not registered for synchronization because synchronization is not active
DEBUG [main] - Cache Hit Ratio [com.hardes.mappers.OrdersMapper]: 0.3333333333333333
DEBUG [main] - Fetching JDBC Connection from DataSource
DEBUG [main] - JDBC Connection [jdbc:mysql:///test?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC, UserName=[email protected], MySQL Connector/J] will not be managed by Spring
DEBUG [main] - ==>  Preparing: SELECT orders.id orders_id, orders.number, orders.user_id, orders.* FROM orders 
DEBUG [main] - ==> Parameters: 
DEBUG [com%002ehardes%002emappers%002e%004frders%004dapper.data] - fault removed 0 from heap
DEBUG [com%002ehardes%002emappers%002e%004frders%004dapper.data] - fault added 0 on disk
DEBUG [main] - <==      Total: 3
DEBUG [main] - put added 0 on heap
DEBUG [main] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6d467c87]
DEBUG [main] - Cache Hit Ratio [com.hardes.mappers.UsersMapper]: 0.0
DEBUG [main] - Fetching JDBC Connection from DataSource
DEBUG [main] - JDBC Connection [jdbc:mysql:///test?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC, UserName=[email protected], MySQL Connector/J] will not be managed by Spring
DEBUG [main] - ==>  Preparing: SELECT * FROM users WHERE id=? 
DEBUG [main] - ==> Parameters: 3(Integer)
DEBUG [main] - <==      Total: 1
DEBUG [main] - put added 0 on heap
DEBUG [main] - Cache Hit Ratio [com.hardes.mappers.UsersMapper]: 0.0
DEBUG [main] - Fetching JDBC Connection from DataSource
DEBUG [main] - JDBC Connection [jdbc:mysql:///test?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC, UserName=[email protected], MySQL Connector/J] will not be managed by Spring
DEBUG [main] - ==>  Preparing: SELECT * FROM users WHERE id=? 
DEBUG [main] - ==> Parameters: 1(Integer)
DEBUG [com%002ehardes%002emappers%002e%0055sers%004dapper.data] - fault removed 0 from heap
DEBUG [com%002ehardes%002emappers%002e%0055sers%004dapper.data] - fault added 0 on disk
DEBUG [main] - <==      Total: 1
DEBUG [main] - put added 0 on heap
DEBUG [main] - Cache Hit Ratio [com.hardes.mappers.UsersMapper]: 0.0
DEBUG [main] - Fetching JDBC Connection from DataSource
DEBUG [com%002ehardes%002emappers%002e%0055sers%004dapper.data] - fault removed 0 from heap
DEBUG [com%002ehardes%002emappers%002e%0055sers%004dapper.data] - fault added 0 on disk
DEBUG [main] - JDBC Connection [jdbc:mysql:///test?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC, UserName=[email protected], MySQL Connector/J] will not be managed by Spring
DEBUG [main] - ==>  Preparing: SELECT * FROM users WHERE id=? 
DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <==      Total: 1
DEBUG [main] - put added 0 on heap
[Orders{oid=1, user_id=3, number='1000', time=Sun Nov 03 21:46:51 SGT 2019, note='eggs', users=Users{id=3, username='sun liu', sex='M', birthday=Tue Aug 27 08:00:00 SGT 2019, address='Woodland Drive'}}, Orders{oid=2, user_id=1, number='2000', time=Mon Oct 07 21:47:26 SGT 2019, note='bread', users=Users{id=1, username='Tom', sex='M', birthday=Sun Oct 06 08:00:00 SGT 2019, address='Jurong East'}}, Orders{oid=3, user_id=2, number='3000', time=Tue Jun 22 23:54:56 SGT 2010, note='Prata', users=Users{id=2, username='Jerry', sex='F', birthday=Mon Jul 08 08:00:00 SGT 2019, address='Tampines West'}}]
DEBUG [main] - Creating a new SqlSession
DEBUG [main] - SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5b5c0057] was not registered for synchronization because synchronization is not active
DEBUG [main] - Cache Hit Ratio [com.hardes.mappers.OrdersMapper]: 0.5
DEBUG [main] - Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5b5c0057]
DEBUG [com%002ehardes%002emappers%002e%004frders%004dapper.data] - fault removed 0 from heap
DEBUG [com%002ehardes%002emappers%002e%004frders%004dapper.data] - fault added 0 on disk
[Orders{oid=1, user_id=3, number='1000', time=Sun Nov 03 21:46:51 SGT 2019, note='eggs', users=Users{id=3, username='sun liu', sex='M', birthday=Tue Aug 27 08:00:00 SGT 2019, address='Woodland Drive'}}, Orders{oid=2, user_id=1, number='2000', time=Mon Oct 07 21:47:26 SGT 2019, note='bread', users=Users{id=1, username='Tom', sex='M', birthday=Sun Oct 06 08:00:00 SGT 2019, address='Jurong East'}}, Orders{oid=3, user_id=2, number='3000', time=Tue Jun 22 23:54:56 SGT 2010, note='Prata', users=Users{id=2, username='Jerry', sex='F', birthday=Mon Jul 08 08:00:00 SGT 2019, address='Tampines West'}}]
DEBUG [com%002ehardes%002emappers%002e%0055sers%004dapper.data] - fault removed 0 from heap
DEBUG [com%002ehardes%002emappers%002e%0055sers%004dapper.data] - fault added 0 on disk
           

指定的路徑生成了緩存資料