Spring整合MyBatis

Author：Exchanges

Version：9.0.2

目录

• Spring整合MyBatis
  • 1. 创建 t_user 表并添加数据
  • 2. pom.xml导入相关依赖
  • 3. 编写pojo
  • 4. 创建 UserController
  • 5. 创建 UserService
  • 6. 创建UserServiceImpl
  • 7. 创建UserMapper
  • 8. 创建mapper目录，然后再创建UserMapper.xml
  • 9. 创建 db.properties
  • 10. 创建log4j.properties
  • 11. 创建mybatis-config.xml
  • 12. 配置applicationContext.xml文件
  • 13. 测试
  • 14. 补充：创建数据源配置类
  • 15. 补充：添加分页操作
    • 15.1添加依赖
    • 15.2 第一种方式：在 applicationContext.xml 中添加配置分页
    • 15.3 第二种方式：在 mybatis-config.xml 中添加配置分页
    • 15.4 在 UserController 中添加方法
    • 15.5 测试

Spring整合MyBatis

---

1. 创建 t_user 表并添加数据

create table t_user(
  id int primary key auto_increment,
  name varchar(50),
  password varchar(50)
)default charset = utf8;

INSERT INTO t_user(NAME,PASSWORD) VALUES("jack","123");
INSERT INTO t_user(NAME,PASSWORD) VALUES("tom","456");
INSERT INTO t_user(NAME,PASSWORD) VALUES("rose","789");

2. pom.xml导入相关依赖

<dependencies>
    <!-- mybatis相关 -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.9</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.29</version>
    </dependency>

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.2.9</version>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.24</version>
    </dependency>

    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13.2</version>
        <scope>test</scope>
    </dependency>

    <!-- spring相关 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.3.20</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.3.20</version>
    </dependency>

    <!-- mybatis整合spring -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>2.0.7</version>
    </dependency>

</dependencies>

3. 编写pojo

package com.qf.pojo;

import lombok.Data;

@Data
public class User {

    private Integer id;
    private String name;
    private String password;

}

4. 创建 UserController

package com.qf.controller;

import com.qf.pojo.User;
import com.qf.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

import java.util.List;

@Controller
public class UserController {
    
    @Autowired
    public UserService userService;
    
    public List<User> findAll(){
        return userService.findAll();
    }
    
}

5. 创建 UserService

package com.qf.service;

import com.qf.pojo.User;

import java.util.List;

public interface UserService {

    List<User> findAll();

}

6. 创建UserServiceImpl

package com.qf.service.impl;

import com.qf.mapper.UserMapper;
import com.qf.pojo.User;
import com.qf.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> findAll() {
        return userMapper.findAll();
    }

}

7. 创建UserMapper

package com.qf.mapper;

import com.qf.pojo.User;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UserMapper {

    List<User> findAll();
}

8. 创建mapper目录，然后再创建UserMapper.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">

<mapper namespace="com.qf.mapper.UserMapper">
    <resultMap id="userMap" type="com.qf.pojo.User">
        <id property="id" column="id"></id>

        <result property="name" column="name"></result>
        <result property="password" column="password"></result>
    </resultMap>

    <sql id="baseSql">
        select id,name,password from t_user
    </sql>

    <select id="findAll" resultMap="userMap">
        <include refid="baseSql"></include>
    </select>

</mapper>

9. 创建 db.properties

db.username = root
db.password = root
db.url = jdbc:mysql://localhost:3306/java2203?serverTimezone=Asia/Shanghai&characterEncoding=UTF8
db.driver = com.mysql.cj.jdbc.Driver

10. 创建log4j.properties

# Global logging configuration
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.ConversionPattern=%5p [%t] - %m%n

11. 创建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>
    
    <!-- 配置日志 -->
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>

</configuration>

12. 配置applicationContext.xml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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- bean definitions here -->

        <!-- 扫描对应包下的注解 -->
        <context:component-scan base-package="com.qf"></context:component-scan>

        <!-- 引入配置文件-->
        <context:property-placeholder location="classpath:db.properties"></context:property-placeholder>

        <!-- 配置数据源 -->
        <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
                <property name="username" value="${db.username}"></property>
                <property name="password" value="${db.password}"></property>
                <property name="url" value="${db.url}"></property>
                <property name="driverClassName" value="${db.driver}"></property>
        </bean>

        <!-- 配置SqlSessionFactory -->
        <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
                <!-- 必选属性，配置dataSource数据源 -->
                <property name="dataSource" ref="dataSource"></property>
                <!-- 非必选属性，可引入mybatis-config.xml配置文件 -->
                <property name="configLocation" value="classpath:mybatis-config.xml"></property>
                <!-- 非必选属性，当Mapper接口和对应的Mapper.xml文件不在同一目录时，
                指定配置Mapper.xml文件的具体位置，这里使用的是通配符配置方式 -->
                <property name="mapperLocations" value="classpath:mapper/*.xml"></property>
        </bean>

        <!-- 扫描Mapper接口，生成代理对象 -->
        <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
                <property name="basePackage" value="com.qf.mapper"></property>
        </bean>

</beans>

13. 测试

package com.qf.test;

import com.qf.controller.UserController;
import com.qf.pojo.User;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.List;

public class SpringTest {

    @Test
    public void test_findAll(){

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

        UserController userController =
                (UserController)applicationContext.getBean("userController");

        List<User> list = userController.findAll();

        System.out.println(list);
    }
}

14. 补充：创建数据源配置类

可以将applicationContext.xml中数据源的相关配置注释掉，使用配置类完成配置

@PropertySource
作用：用于指定properties文件的位置
属性：value：指定文件的名称和路径。
关键字：classpath，表示类路径下

等同于xml中: <context:property-placeholder location="classpath:db.properties"/>

@Configuration
作用：指定当前类是一个配置类，服务器启动后会先加载

@Bean
作用：用于把当前方法的返回值作为bean对象存入spring的ioc容器中
属性: name和value: 用于指定bean的id，当不写时，默认值是当前方法的名称

package com.qf.config;

import com.alibaba.druid.pool.DruidDataSourceFactory;
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 javax.sql.DataSource;
import java.util.Properties;

@PropertySource(value = "classpath:db.properties")
@Configuration
public class DataSourceConfig {

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

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

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

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

    @Bean("dataSource")
    public DataSource getDataSource(){

        Properties pro = new Properties();
        pro.setProperty("url",url);
        pro.setProperty("username",username);
        pro.setProperty("password",password);
        pro.setProperty("driverClassName",driverClassName);

        DataSource dataSource = null;

        try {
            dataSource = DruidDataSourceFactory.createDataSource(pro);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return dataSource;

    }
}

15. 补充：添加分页操作

15.1添加依赖

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper</artifactId>
    <version>5.3.0</version>
</dependency>

15.2 第一种方式：在 applicationContext.xml 中添加配置分页

<?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" xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- bean definitions here -->

        <!-- 扫描对应包下的注解 -->
        <context:component-scan base-package="com.qf"></context:component-scan>

        <!-- 引入配置文件-->
<!--        <context:property-placeholder location="classpath:db.properties"></context:property-placeholder>-->

        <!-- 配置数据源 -->
<!--        <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">-->
<!--                <property name="username" value="${db.username}"></property>-->
<!--                <property name="password" value="${db.password}"></property>-->
<!--                <property name="url" value="${db.url}"></property>-->
<!--                <property name="driverClassName" value="${db.driver}"></property>-->
<!--        </bean>-->

        <!-- 配置SqlSessionFactory -->
        <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
                <!-- 必选属性，配置dataSource数据源 -->
                <property name="dataSource" ref="dataSource"></property>
                <!-- 非必选属性，可引入mybatis-config.xml配置文件 -->
                <property name="configLocation" value="classpath:mybatis-config.xml"></property>
                <!-- 非必选属性，当Mapper接口和对应的Mapper.xml文件不在同一目录时，
                指定配置Mapper.xml文件的具体位置，这里使用的是通配符配置方式 -->
                <property name="mapperLocations" value="classpath:mapper/*.xml"></property>

                <!-- 分页配置 -->
                <!-- 配置插件 -->
                <property name="plugins">
                        <array>
                                <bean class="com.github.pagehelper.PageInterceptor">
                                        <property name="properties">
                                        <!--使用下面的方式配置参数，一行配置一个 -->
                                                <value>
                                                        helperDialect=mysql
                                                        reasonable=true
                                                        supportMethodsArguments=true
                                                </value>
                                        </property>
                                </bean>
                        </array>
                </property>

        </bean>

        <!-- 扫描Mapper接口，生成代理对象 -->
        <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
                <property name="basePackage" value="com.qf.mapper"></property>
        </bean>

</beans>

15.3 第二种方式：在 mybatis-config.xml 中添加配置分页

<?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>
    
    <!-- 配置日志 -->
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>

    <plugins>
        <plugin interceptor="com.github.pagehelper.PageInterceptor">
            <property name="helperDialect" value="mysql"/>
            <property name="reasonable" value="true"/>
            <property name="supportMethodsArguments" value="true"/>
        </plugin>
    </plugins>

</configuration>

15.4 在 UserController 中添加方法

public PageInfo<User> findByPage(Integer pageNum,Integer pageSize){

    PageHelper.startPage(pageNum,pageSize);

    List<User> userList = userService.findAll();

    PageInfo<User> userPageInfo = new PageInfo<>(userList);

    return userPageInfo;
}

15.5 测试

@Test
public void test_findByPage(){

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

    UserController userController =
        (UserController)applicationContext.getBean("userController");

    PageInfo<User> pageInfo = userController.findByPage(0,2);

    System.out.println(pageInfo.getList());
}