Spring连接MyBatis

MyBatis与Spring连接需要的包

<?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>org.example</groupId>
    <artifactId>Module-05-MyBatis</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.0.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
            <scope>runtime</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
    <!-- 添加xml文件过滤 -->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>
</project>

连接步骤

1. 实体类

   package org.example.pojo;
   
   import lombok.Data;
   
   @Data
   public class User {
       public int id;
       public String name;
       public String pwd;
   }
   

2. 核心配置文件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>
       <typeAliases>
           <package name="org.example.pojo"/>
       </typeAliases>
   
       <environments default="development">
           <environment id="development">
               <transactionManager type="JDBC"/>
               <dataSource type="POOLED">
                   <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                   <property name="url" value="jdbc:mysql://127.0.0.1:3306/test?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8&amp;allowMultiQueries=true"/>
                   <property name="username" value="${username}"/>
                   <property name="password" value="${password}"/>
               </dataSource>
           </environment>
       </environments>
   
       <mappers>
           <mapper class="org.example.mapper.UserMapper"/>
       </mappers>
   </configuration>
   

3. 接口

   每个实体类对应一个mapper接口，通常将接口文件放在mapper包下。同时每个接口对应一个xml配置文件。

   package org.example.mapper;
   
   import org.example.pojo.User;
   
   import java.util.List;
   
   public interface UserMapper {
       public List<User> selectUser();
   }
   

4. Mapper.xml

   每个实体类接口在同一包下对应一个xml配置文件

   <?xml version="1.0" encoding="UTF-8" ?>
   <!DOCTYPE mapper
           PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
           "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
   <mapper namespace="org.example.mapper.UserMapper">
       <select id="selectUser" resultType="user">
           select * from user;
       </select>
   
   </mapper>
   

5. 测试

   package org.example.pojo;
   
   import org.apache.ibatis.io.Resources;
   import org.apache.ibatis.session.SqlSession;
   import org.apache.ibatis.session.SqlSessionFactory;
   import org.apache.ibatis.session.SqlSessionFactoryBuilder;
   import org.example.mapper.UserMapper;
   import org.junit.Test;
   
   import java.io.IOException;
   import java.io.InputStream;
   import java.util.List;
   
   public class MyTest {
       @Test
       public void myTest() throws IOException {
           String resources = "mybatis-config.xml";
           InputStream inputStream = Resources.getResourceAsStream(resources);
           SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
           SqlSession sqlSession = sessionFactory.openSession(true);
   
           UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
           List<User> userList = userMapper.selectUser();
   
           for (User user : userList) {
               System.out.println(user);
           }
       }
   }