SpringBoot mybatis integration and Notes

SpringBoot mybatis integration and Notes

The main steps

1. Add rely mybatis
2. Configuration data in the configuration file source information
3. Write pojo mapper interfaces mapeer mapping file
4. Manual configuration package scanning mybatis

Add @MapperScan the main startup class

1: import dependencies

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

2: Configuration Data source information

In the configuration application.yml

#DB Configation
spring:
  datasource:
    driverClassName: com.mysql.jdbc.Driver
　　　// Note If you can not connect to the database problem GMT, adding later tx useUnicode = true & characterEncoding = utf -8 & useSSL = false & serverTimezone = appear? 
    Url: jdbc: MySQL: // 127.0.0.1:3306/tx 
    username: root
    password: 813100
  jpa:
    database: MySQL
    show-sql: true
    generate-ddl: true

3: Writing pojo entity class and the corresponding interface and a mapper mapping file

pojo entity class

package com.offcn.springbootdemo1.pojo;


public class UUser {

    Private Integer ID;
     Private String username;
     Private String password;
     Private String name;
　　// add here set, get, and rewriting constructor toString 
}

mapper Interface

package com.offcn.springbootdemo1.mapper;

import com.offcn.springbootdemo1.pojo.UUser;

import java.util.List;

public  interface UUserMapper {
    List<UUser> selectUUser();
}

mapper mapping file

<?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