Spring Boot中使用MyBatis

整合MyBatis之前，先搭建一个基本的Spring Boot项目[。然后引入spring-boot-mybatis和数据库连接驱动（这里使用关系型数据库mysql）

添加mysql和mybaties的依赖

• 这里用到spring-boot-starter基础和spring-boot-starter-test用来做单元测试验证数据访问
• 引入连接mysql的必要依赖mysql-connector-java
• 引入整合MyBatis的核心依赖mybatis-spring-boot-starter
• 这里不引入spring-boot-starter-jdbc依赖，是由于mybatis-spring-boot-starter中已经包含了此依赖

在pom文件中添加：

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.tcbj</groupId>
    <artifactId>spring-boot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-mybatis</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--Mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>

        <!--Mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

不同版本的Spring Boot和MyBatis版本对应不一样，具体可查看官方文档：http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/。

• 在application.properties中配置mysql的连接配置

spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

使用MyBatis

• 在Mysql中创建User表，包含id(BIGINT)、name(INT)、age(VARCHAR)字段。同时，创建映射对象User

@Getter
@Setter
public class User {
    private Long id;
    private String name;
    private Integer age;
}

• 创建User映射的操作UserMapper，为了后续单元测试验证，实现插入和查询操作

@Mapper
public interface UserMapper {

    @Select("select * from User Where Name = #{name}")
    User findByName(@Param("name") String name);

    @Insert("insert into user(name,age) values(#{name},#{age})")
    int insert(@Param("name") String name, @Param("age") Integer age);
}

• 创建单元测试
  • 测试逻辑：插入一条name=AAA，age=20的记录，然后根据name=AAA查询，并判断age是否为20

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class SpringBootMybatisApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    @Rollback
    public void findByName() throws Exception {
        userMapper.insert("AAA", 20);
        User u = userMapper.findByName("AAA");
        Assert.assertEquals(20, u.getAge().intValue());
    }
}