MyBatis笔记1 开始使用

本节写个简单的Spring + MyBatis + MySQL应用

• Step 1. 新建一个目录：D:\Workspaces\MyStudyRepository\StudyMybatis
  
• Step 2. 运行：gradle init --type java-library
• Step 3. 在Eclipse中import gradle project, 选择这个目录
• Step 4. 在build.gradle中，加入需要的依赖

compile group: 'org.mybatis', name: 'mybatis', version: '3.4.2'

compile group: 'org.mybatis', name: 'mybatis-spring', version: '1.3.1'

compile group: 'mysql', name: 'mysql-connector-java', version: '6.0.5'

• Refresh Gradle Project, 下载jar包
• Step 5. 在Mysql中创建两个表做例子

CREATE TABLE `t_product_category` (

  `Id` int(11) NOT NULL AUTO_INCREMENT,

  `name` varchar(255) NOT NULL DEFAULT '',

  PRIMARY KEY (`Id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `t_product` (

  `Id` int(11) NOT NULL AUTO_INCREMENT,

  `name` varchar(255) NOT NULL DEFAULT '',

  `product_category_id` int(11) NOT NULL DEFAULT '0',

  PRIMARY KEY (`Id`),

  KEY `FK_PRODUCT_CATEGORY_ID` (`product_category_id`),

  CONSTRAINT `FK_PRODUCT_CATEGORY_ID` FOREIGN KEY (`product_category_id`) REFERENCES `t_product_category` (`Id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

• Step 6. 在Eclipse中，查找并安装插件：MyBatis Generator, 当前版本：1.3.5 (http://www.mybatis.org/generator/)
• Step 7. File/New/Others/MyBatis Generator Configuration File
  • 建立在StudyMybatis根目录下"generatorConfig.xml"， 文件内容

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>

  <classPathEntry    location="D:\gradle_repo\caches\modules-2\files-2.1\Mysql\mysql-connector-java\6.0.5\9d8df5a1f3273110f2a9ad304961bdd03d696d86\mysql-connector-java-6.0.5.jar"/>

  <context id="context1">

    <jdbcConnection 

        connectionURL="jdbc:mysql://***" 

        driverClass="com.mysql.cj.jdbc.Driver" 

        password="***" 

        userId="***" />

    <javaModelGenerator targetPackage="com.cloudboy.mybatis.model" targetProject="StudyMybatis\src\main\java" />

    <sqlMapGenerator targetPackage="mybatis" targetProject="StudyMybatis\src\main\resources" />

    <javaClientGenerator targetPackage="com.cloudboy.mybatis.mapper" targetProject="StudyMybatis\src\main\java" type="XMLMAPPER" />

    <table schema="feitu" tableName="t_product_category">

    </table>

    <table schema="feitu" tableName="t_product">

    </table>

  </context>

</generatorConfiguration>  

• 文件里配置了数据库连接URL及用户名密码，此工具需要读取数据库表结构，以便自动生成代码和配置xml
• javaModelGenerator: 配置java数据模型存放的位置
• sqlMapGenerator: 配置xml配置文件存放的位置
• javaClientGenerator: 配置java DAO接口文件的位置
• 配置了我们新建的两个表t_product_category, t_product
• Step 8. 右键点击这个文件，选择Run As/Run MyBatis Generator, 以下文件自动生成出来：
  • src/main/java/com.cloudboy.mybatis.model包下
    • TProduct.java    数据模型类，对应表T_PRODUCT
    • TProductCategory.java  数据模型类，对应表T_PRODUCT_CATEGORY
    • TProductExample.java 用来生成表T_PRODUCT查询条件的辅助类
      
    • TProductCategoryExample.java 用来生成表T_PRODUCT_CATEGORY查询条件的辅助类
      
  • src/main/java/com.cloudboy.mybatis.mapper包下
    • TProductMapper.java    // 访问表T_PRODUCT的接口，相当于DAO
      
    • TProductCategoryMapper.java  // 访问表T_PRODUCT_CATEGORY的接口，相当于DAO
      
  • src/main/resources/mybatis下
    • TProductMapper.xml   // 表的mapper配置
      
    • TProductCategoryMapper.xml          // 表的mapper配置
      
• Step 9. 新建  src/main/resources/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>

    <mappers>  

        <mapper resource="mybatis/TProductMapper.xml"/>

        <mapper resource="mybatis/TProductCategoryMapper.xml"/>

    </mappers>

</configuration>  

• 里面包含了2个表的Mapper
• Step 10. 新建 src/main/resources/myBatisBean.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"

    xmlns:aop="http://www.springframework.org/schema/aop"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

        http://www.springframework.org/schema/aop

        http://www.springframework.org/schema/aop/spring-aop-2.5.xsd

        http://www.springframework.org/schema/context

        http://www.springframework.org/schema/context/spring-context-2.5.xsd">

    

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName">

            <value>com.mysql.cj.jdbc.Driver</value>

        </property>

        <property name="url">

            <value>jdbc:mysql://mysql.rdsm5qi8p7obva1.rds.gz.baidubce.com/feitu?useUnicode=true&characterEncoding=UTF-8</value>

        </property>

        <property name="username">

            <value>sysfeitu</value>

        </property>

        <property name="password">

            <value>xy65390856</value>

        </property>

    </bean>  

    

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

          <property name="dataSource" ref="dataSource" />

          <property name="configLocation" value="classpath:mybatis/mybatis-config.xml"></property>  

    </bean>

    

    <bean id="productMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">  

        <property name="mapperInterface" value="com.cloudboy.mybatis.mapper.TProductMapper"></property>  

        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>  

    </bean>

    

    <bean id="productCategoryMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">  

        <property name="mapperInterface" value="com.cloudboy.mybatis.mapper.TProductCategoryMapper"></property>  

        <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>  

    </bean>

</beans>

• 定义了数据库连接方式
• 定义了两个Mapper bean
• Step 11. 写一个总的spring配置文件：/src/main/resources/applicationContext.xml, 里面import myBatisBean.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:context="http://www.springframework.org/schema/context"

    xmlns:aop="http://www.springframework.org/schema/aop"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

        http://www.springframework.org/schema/aop

        http://www.springframework.org/schema/aop/spring-aop-2.5.xsd

        http://www.springframework.org/schema/context

        http://www.springframework.org/schema/context/spring-context-2.5.xsd">

    <context:annotation-config />

    <aop:aspectj-autoproxy />

    <import resource="classpath:mybatis/myBatisBean.xml"/>

</beans>  

• Step 12. 写测试类

package com.cloudboy.mybatis;

import java.util.List;

import org.junit.BeforeClass;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.cloudboy.mybatis.mapper.TProductCategoryMapper;

import com.cloudboy.mybatis.model.TProductCategory;

import com.cloudboy.mybatis.model.TProductCategoryExample;

import com.thoughtworks.xstream.XStream;

public class ProductCategoryTest {

    private static ApplicationContext ctx;

    private static TProductCategoryMapper dao = null;

    private static XStream xs = new XStream();

    @BeforeClass

    public static void setUpBeforeClass() throws Exception {

        ctx = new ClassPathXmlApplicationContext("applicationContext.xml");

        dao = (TProductCategoryMapper)ctx.getBean("productCategoryMapper");

    }

    @Test

    public void testInsert() {

        for(int i=0; i<10; i++) {

            TProductCategory data = new TProductCategory();

            data.setName("商品" + i);

            dao.insert(data);

        }

    }

    

    @Test

    public void testSelect() {

        TProductCategoryExample example = new TProductCategoryExample();

        // 啥条件也不写，则返回全部记录

        List<TProductCategory> result = dao.selectByExample(example);

        System.out.println(xs.toXML(result));

        

        // 选择id在3~5的记录

        example.createCriteria().andIdBetween(3, 5);

        result = dao.selectByExample(example);

        System.out.println(xs.toXML(result));

    }

    

    @Test

    public void testUpdate() {

        TProductCategory data = new TProductCategory();

        data.setId(4);

        data.setName("旅游4");

        TProductCategoryExample example = new TProductCategoryExample();

        example.createCriteria().andIdEqualTo(4);

        dao.updateByExample(data, example);

    }

}

本例的依赖

dependencies {

    testImplementation 'junit:junit:4.12'

    testImplementation  group:'com.thoughtworks.xstream', name:'xstream', version:'1.4.7'

    testImplementation  group:'xmlpull', name:'xmlpull', version:'1.1.3.4d_b4_min'

    compile group: 'org.mybatis', name: 'mybatis', version: '3.4.2'

    compile group: 'org.mybatis', name: 'mybatis-spring', version: '1.3.1'

    compile group: 'mysql', name: 'mysql-connector-java', version: '6.0.5'

    compile group: 'org.springframework', name: 'spring-context', version: '4.3.8.RELEASE'

    compile group: 'org.springframework', name: 'spring-jdbc', version: '4.3.8.RELEASE'

    compile group: 'org.aspectj', name: 'aspectjrt', version: '1.8.10'

}