Spring 集成 Mybatis（包含xml和注解两种方式）

最新推荐文章于 2025-09-17 17:59:57 发布

原创最新推荐文章于 2025-09-17 17:59:57 发布 · 1.2k 阅读

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#mybatis #spring #java

Mybatis 简介

1.1 什么是Mybatis

MyBatis 是一款优秀的持久层框架，他支持自定义Sql，存储过程以及高级映射，MyBatis免除了几乎所有JDBC代码以及设置参数和获取结果集的工作，MyBatis可以通过简单的xml或这届来配置和映射原始类型，接口和java pojo 为数据库中的记录

MyBats官网

mybatis – MyBatis 3 | 简介

1.2 为什么是Mybatis

1）Mybatis 是一个半自动的持久化层框架

2）jdbc

3) Hibernate & Spring Data Jpa

长难度复杂sql,对于Hinbernate 而言处理也不容易

内部自动生成sql,不容易做特殊优化

全映射的全自动框架，大量自动的pojo进行部分映射时比较困难，导致数据库性能下降

1.3 ORM框架

ORM 表示 Object-RelationalMapping 。他时一个思想，其本质是吧数据库中的数据用对象来表示

2.xml文件配置Mybatis

2.1 导入依赖

<!--测试-->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>5.2.9.RELEASE</version>
</dependency>
<!--spring核心包-->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.2.9.RELEASE</version>
</dependency>
<!--Mybatis-->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.3</version>
</dependency>
<!--mybatis和spring集成的-->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>2.0.3</version>
</dependency>
<!--lombok-->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.0</version>
</dependency>
<!--Druid连接池-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.1.6</version>
</dependency>
<!--mysql驱动-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.17</version>
</dependency>

2.2 项目结构

【注意，config,dao,service包,SpringConfiguration类】是全注解配置时使用的，target包下如果没有mapper的编译文件，重新编译一下项目

2.3 编写Mybatis-config.xml 配置文件

<?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>
        <!--开启驼峰命名规则-->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <!--延迟加载的全局开关-->
        <setting name="lazyLoadingEnabled" value="true"/>
        <!--开启按需加载的开关-->
        <setting name="aggressiveLazyLoading" value="false"/>
        <!--开启二级缓存-->
        <setting name="cacheEnabled" value="true"/>
    </settings>
</configuration>

2.4 编写druid.properties 数据库配置文件

【注意】：我使用的MySql是8.0，请大家改成对应的

jdbc.driverClassName=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/cs?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8&useUnicode=yes
jdbc.username=root
jdbc.password=root

2.5 遍application.xml配置文件

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.alibaba.com/schema/stat"
       xmlns:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.alibaba.com/schema/stat http://www.alibaba.com/schema/stat.xsd http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring.xsd">

    <!--开启组件扫描-->
    <context:component-scan base-package="cn.zb.spring"/>

    <!--引入外部数据库配置文件-->
    <context:property-placeholder location="classpath:druid.properties"/>

    <!--配置数据库连接池-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <!--注册事务管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <!--开启事务的注解-->
    <tx:annotation-driven/>

    <!--配置接口扫描，因为UsersMapper.java没有实现类，所以必须依靠cglib在内存里构造代理对象-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--注入mapper接口所在的包-->
        <property name="basePackage" value="cn.zb.spring.mapper"/>
        <!--注入sqlSessionFactoryBeanName 也就时IOC容器里面的sqlSessionFactory-->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

    <!--在Spring容器中注册sqlSessionFactory的实例-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!--配置mybatis主配置文件-->
        <property name="configLocation" value="classpath:Mybatis-config.xml"/>
        <!--别名配置  可以修改别名的包路径-->
        <property name="typeAliasesPackage" value="cn.zb.spring.entity" />
        <!--配置 XML映射-->
        <property name="mapperLocations" value="classpath*:mapper/*.xml" />
    </bean>

    <!--批量配置映射器  可以修改映射器包路径-->
    <!--映射xml文件-->
    <!--<mapper resource="cn/zb/spring/mapper/UsersMapper.xml"/>-->
    <!--映射接口类-->
    <!--<mapper class="cn.zb.spring.mapper"/>-->
    <!--整个包映射-->
    <mybatis-spring:scan base-package="cn.zb.spring.mapper"/>

</beans>

3. Spring 整合lombok

3.1 下载插件，依赖前面导过了

3.2 编写实体类，了解Lombok基础注解

【注意】：实体类字段应于数据库字段对应，且是驼峰命名法

package cn.zb.spring.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data //提供类所有属性的get,set方法，此外还提供了equals,canEqual,hashCode.toString方法
@AllArgsConstructor //提供全参的构造方法
@NoArgsConstructor //提供无参的构造方法
public class Users {

    private Long userId;

    private String userName;

    private String userPwd;
}

3.3 编写UsersMapper接口以及UsersMapper.xml文件

package cn.zb.spring.mapper;

import cn.zb.spring.entity.Users;
import org.springframework.stereotype.Repository;

@Repository
public interface UsersMapper {
    //根据id查询，返回Users对象，方法名与UsersMapper.xml中id对应
    Users getByUserId(int userId);
    
    //查询所有
    List<Users> getAll();
}

【注意】： #{value} ,${value}都是占位符，${value} 有sql注入的风险，不会区分数据类型

<?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="cn.zb.spring.mapper.UsersMapper">

    <select id="getByUserId" resultType="cn.zb.spring.entity.Users">
        select * from users where user_id=#{userId}
    </select>
    <select id="getAll" resultType="cn.zb.spring.entity.Users">
        select * from users
    </select>
</mapper>

3.4 编写测试类

package cn.zb.test;

import cn.zb.spring.entity.Users;
import cn.zb.spring.mapper.UsersMapper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:application.xml")
public class SpringTest {

    @Autowired
    private UsersMapper usersMapper;

    @Test
    public void test1(){
        Users users = usersMapper.getByUserId(1);
        System.out.println(users);
    }

    @Test
    public void test2(){
        int pageIndex=0; //分页插件从0开始查
        int pageSize=5;
        PageInfo<Object> pageInfo = PageHelper.startPage(pageIndex,             pageSize).doSelectPageInfo(() -> usersMapper.getAll());
        //获取的对象集合
        pageInfo.getList().forEach(System.out::println);
        //表中共有多少数据条数
        System.out.println(pageInfo.getTotal());
    }
}

4. 通过注解配置Mybatis

4.1 编写SpringConfiguration配置类代替 application.xml

package cn.zb.spring;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@ComponentScan("cn.zb.spring") //开启包扫描
//@EnableAspectJAutoProxy(proxyTargetClass = true)
@EnableTransactionManagement //开启事务
@MapperScan("cn.zb.spring.mapper")
@Import({MybatisConfig.class}) //引入Mybatis配置类
public class SpringConfiguration {
}

4.2 编写DuridConfig类替代application.xml 中的数据源配置

package cn.zb.spring.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

@Configuration
@PropertySource(value = "classpath:druid.properties") //引入druid配置文件
public class DruidConfig {

    @Value("${jdbc.driverClassName}")
    private String driverClassName;

    @Value("${jdbc.url}")
    private String url;

    @Value("${jdbc.username}")
    private String username;

    @Value("${jdbc.password}")
    private String password;

    @Bean
    public DruidDataSource getDDruidDataSource(){
        DruidDataSource dataSource=new DruidDataSource();
        dataSource.setDriverClassName(driverClassName);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }
//    不通过配置文件获取，直接传属性
//    @Bean
//    public DruidDataSource getDDruidDataSource(){
//        DruidDataSource dataSource=new DruidDataSource();
//        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
//        dataSource.setUrl("jdbc:mysql://localhost:3306/cs?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8&useUnicode=yes");
//        dataSource.setUsername("root");
//        dataSource.setPassword("root");
//        return dataSource;
//    }

    //创建JdbcTemplate对象
    @Bean
    public JdbcTemplate getJdbcTemplate(DataSource dataSource){
        JdbcTemplate jdbcTemplate=new JdbcTemplate();
        jdbcTemplate.setDataSource(dataSource);
        return jdbcTemplate;
    }
}

4.3 编写MybatisConfig配置类，替代application.xml的Mybait配置

package cn.zb.spring.config;

import org.apache.ibatis.session.Configuration;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;

public class MybatisConfig {

    @Bean
    public SqlSessionFactoryBean sqlSessionFactoryBean(@Autowired DataSource dataSource) {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        sqlSessionFactoryBean.setTypeAliasesPackage("cn.zb.spring.entity");
        Configuration configuration = new Configuration();
        configuration.setMapUnderscoreToCamelCase(true);
        sqlSessionFactoryBean.setConfiguration(configuration);
        return sqlSessionFactoryBean;
    }

}

4.4 编写UsersMapper，使用注解开发接口

package cn.zb.spring.mapper;

import cn.zb.spring.entity.Users;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UsersMapper {
    //根据id查询，返回Users对象，方法名与UsersMapper.xml中id对应
    @Select("select * from users where user_id=#{userId}")
    //@Update("sql") //修改
    //@Delete("sql") //删除
    //@Insert("sql") //新增
    Users getByUserId(int userId);

    @Select("select * from users")
    List<Users> getAll();
}

4.5 编写测试类

package cn.zb.test;


import cn.zb.spring.SpringConfiguration;

import cn.zb.spring.mapper.UsersMapper;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class) //替换原来的运行期
@ContextConfiguration(classes = {SpringConfiguration.class}) //指定配置文件或配置类
public class SpringJunitTest {

    @Autowired
    private UsersMapper usersMapper;

    @Test
    public void test1(){
        System.out.println(usersMapper.getByUserId(1));
    }

    @Test
    public void test2(){
        int pageIndex=0; //分页插件从0开始查
        int pageSize=5;
        PageInfo<Object> pageInfo = PageHelper.startPage(pageIndex, pageSize).doSelectPageInfo(() -> usersMapper.getAll());
        //获取的对象集合
        pageInfo.getList().forEach(System.out::println);
        //表中共有多少数据条数
        System.out.println(pageInfo.getTotal());
    }

}

本文仅做记录使用，参考其他的文献