SpringBoot整合mybatis及注意事项

主要步骤

1. 添加依赖 mybatis
2. 在配置文件中配置数据源信息
3. 编写pojo mapper接口 mapeer映射文件
4. 手动配置mybatis的包扫描

​ 　　　　在主启动类添加@MapperScan

1：导入依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.1.1</version>
</dependency>

2：配置数据源信息

在application.yml中进行配置

#DB Configation spring: datasource: driverClassName: com.mysql.jdbc.Driver 　　　//注意如果出现了无法连接数据库问题，在tx后面添加 ?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone = GMT
    url: jdbc:mysql://127.0.0.1:3306/tx
 username: root password: 813100 jpa: database: MySQL show-sql: true generate-ddl: true

3：书写pojo实体类和对应的mapper接口及映射文件

pojo实体类

package com.offcn.springbootdemo1.pojo; public class UUser { private Integer id; private String username; private String password; private String name; 　　//此处添加set，get，构造方法以及重写toString
}

mapper接口

package com.offcn.springbootdemo1.mapper; import com.offcn.springbootdemo1.pojo.UUser; import java.util.List; public interface UUserMapper { List<UUser> selectUUser(); }

mapper映射文件

<?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.offcn.springbootdemo1.mapper.UUserMapper">
<select id="selectUUser" resultType="com.offcn.springbootdemo1.pojo.UUser"> select * from user </select>
</mapper>

注意：如果mapper接口和mapper映射文件放在同一个地方

那么在运行会出现错误

解决方案：

1：在resources目录下建立一个和mapper接口相同的目录结构，把mapper映射文件放进去

2：如果想把mapper接口和mapper映射文件放在一起

那么在pom.xml中添加如下配置

　　<build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include> <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.*</include> </includes> <filtering>false</filtering> </resource> </resources> </build>

4：手动配置mybatis扫描 

 在启动类上添加注解@MapperScan 

package com.offcn.springbootdemo1; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication @MapperScan(basePackages = "com.offcn.springbootdemo1.mapper") public class Springbootdemo1Application { public static void main(String[] args) { SpringApplication.run(Springbootdemo1Application.class, args); } }

5：在Controller中进行测试

package com.offcn.springbootdemo1.controller; //导包
 @Controller public class UUserController { @Resource private UUserMapper userMapper; @RequestMapping("aa") @ResponseBody public List<UUser> selectUUser(){ List<UUser> uUsers = userMapper.selectUUser(); return uUsers; } }

6：在浏览器中及结果