Spring Boot学习笔记(五)整合mybatis

pom文件里添加依赖

　　　　<!-- 数据库需要的依赖 -->        
　　
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>

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

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.0</version>
        </dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>

application.properties
我用的是springBoot 2.1 不需要配置驱动，配置驱动的话反而会出现警告

#数据库
spring.datasource.url=jdbc:mysql://192.168.238.130:3306/dev?useUniode=true&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123

Mapper.java文件

import java.util.ArrayList;

import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Many;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

import com.sc.Firstboot.entity.User;

public interface MainMapper {

    /**
     * 简单查询的话可以用下面这中注解的方式，比较简洁
     * 复杂查询还是需要用到mapper.xml配置文件来完成
     * @return
     */

    @Select("select * from user")
    public ArrayList<User> find();

    @Insert("insert into user(id,username,age,pwd) values(#{id},#{username},#{age},#{pwd})")
    public int insert(@Param("id") String id, @Param("username") String username, @Param("age") int age,
            @Param("pwd") String pwd);

    public ArrayList<User> findAllAndPro();
}

Mapper.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.sc.Firstboot.dao.MainMapper">

    <select id="findAllAndPro" resultMap="userMap">
        select
        us.id,us.username,us.pwd,us.age,pru.id as pid ,
        pru.productName,pru.price,pru.total
        from user us
        left join product pru on pru.uid = us.id
    </select>

    <!-- 注意：当多个表的字段名一样的时候，查询需要用别名，否则查询结果不理想 -->
    <resultMap id="userMap" type="com.sc.Firstboot.entity.User">
        <id property="id" column="id" />
        <result property="userName" column="userName" />
        <result property="pwd" column="pwd" />
        <result property="age" column="age" />
        <collection property="pList" ofType="com.sc.Firstboot.entity.Product">
            <id property="id" column="pid" />
            <result property="productName" column="productName" />
            <result property="total" column="total" />
        </collection>
    </resultMap>

</mapper>

service

@Service
public class MainService {

    @Autowired
    private MainMapper mainMapper;

    public String insert(User user){
        if(1 == mainMapper.insert("ewq", user.getUserName(),user.getAge(), user.getPwd()))return "success";
        return "faild";
    }

    public ArrayList<User> findAll(){
        return mainMapper.find();
    }

    public ArrayList<User> findAllAndPro(){
        return mainMapper.findAllAndPro();
    }

}

controller

@Controller
public class MainController {

    @Autowired
    private MainService mainSerice;

    /**
     * 传参的时候需要注意区分命名，尽量不要使用相同的命名，
     * 否则的框架会给形参列表中所有的实体里所有相同的属性名都赋值
     * 例如 User实体和Product实体中都有id属性
     * 那么传参的时候如果  id=XXX 那么两个实体的id都会被赋值XXX
     * @param user
     * @param product
     * @return
     */
    @ResponseBody
    @RequestMapping(path = {"/insertUser"}, method = {RequestMethod.GET, RequestMethod.POST})
    public String insertUser(User user,Product product){
        System.out.println(user.toString());
        System.out.println(product.toString());
        return mainSerice.insert(user);
    }

    @ResponseBody
    @RequestMapping(path = {"/findAll"}, method = {RequestMethod.GET, RequestMethod.POST})
    public ModelAndView findAll(){
        ModelAndView mv = new ModelAndView();
        Map<String,Object> map = new HashMap<>();
        map.put("userList",mainSerice.findAll());
        mv.setViewName("login/login");
        mv.addObject("result",map);
        return mv;
    }

    @ResponseBody
    @RequestMapping(path = {"/findAllAndPro"}, method = {RequestMethod.GET, RequestMethod.POST})
    public ModelAndView findAllAndPro(){
        ModelAndView mv = new ModelAndView();
        Map<String,Object> map = new HashMap<>();
        map.put("userList",mainSerice.findAllAndPro());
        mv.setViewName("login/login");
        mv.addObject("result",map);
        return mv;
    }
}

Application.java

/**
 * 启动mapper文件的扫描注解
 * 他会去制定的包范围下扫描所有以Mapper接吻的java文件
 * 默认扫整个项目
 * @author lenovo
 *
 */
@SpringBootApplication
@MapperScan(basePackages={"com.sc.myProject.dao"})
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}