SpringBoot(第篇)：整合MyBatis

SpringBoot

项目springdemo1

前言

引入依赖

<!--springboot-mybatis整合包-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>
<!--mysql-jdbc驱动-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!--druid连接池-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.0.29</version>
</dependency>        

application.properties 添加相关配置

# 连接池配置
spring.datasource.url=jdbc:mysql://localhost/jfinal_demo?characterEncoding=utf8&zeroDateTimeBehavior=convertToNull
spring.datasource.password=root
spring.datasource.username=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver  
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource 

springboot会自动加载spring.datasource.*相关配置，数据源就会自动注入到sqlSessionFactory中，sqlSessionFactory会自动注入到Mapper中，对了你一切都不用管了，直接拿起来使用就行了。

以上的配置修改了springboot的默认数据库连接池为druid

创建User类

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@ToString
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);
}

单元测试

@RunWith(SpringRunner.class)
@SpringBootTest
public class Springdemo1ApplicationTests {
    @Autowired
    private UserMapper userMapper;
    @Test
    @Rollback
    public void findByName() throws Exception {
        userMapper.insert("bbbc", 20);
        User u = userMapper.findByName("bbbc");
        System.out.println(u);
    }
}

优化

UserMapper.java
去掉@Mapper注解
去掉@Select @Insert注解
最后变成

public interface UserMapper {
    User findByName(@Param("name") String name);
    int insert(@Param("name") String name, @Param("age") Integer age);
}

因为去掉@Mapper注解，所以Spring找不到该bean

@SpringBootApplication
@MapperScan("com.chen.springdemo1.mapper")
public class Springdemo1Application {
    public static void main(String[] args) {
        SpringApplication.run(Springdemo1Application.class, args);
    }
}

在UserMapper.java同级目录下创建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.chen.springdemo1.mapper.UserMapper">
    <select id="findUserById" parameterType="int" resultType="com.chen.springdemo1.domain.User">
        select * from user where id=#{id}
    </select>
</mapper>

在pom.xml添加

<!--在pom文件中的build标签中添加这段配置,让在src下的资源也能加载到classes目录-->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>