SpringBoot整合Mybatis进行数据持久化

1.SpringBoot构建已经Maven工程搭建

选择依赖：将Web内的Spring Web导入

2.修改配置文件：使用yml语法

将application.properties文件删除，创建application.yml配置文件（备注：其实SpringBoot底层会把application.yml文件解析为*application.properties*）

application.yml

spring:
  profiles:
    active: dev

application-dev.yml

server:
  port: 8080

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis:
  mapper-locations: classpath:mybatis/UserMapper.xml
  type-aliases-package: com.example.springboot.pojo

#showSql
logging:
  level:
    com:
      example:
        mapper : debug

注意：在实际项目中通常不使用application.properties来进行配置。

因为现在一个项目有好多环境，开发环境，测试环境，准生产环境，生产环境，每个环境的参数不同，所以我们就可以把每个环境的参数配置到yml文件中，这样在想用哪个环境的时候只需要在主配置文件中将用的配置文件写上就行如application.yml

笔记：在Spring Boot中多环境配置文件名需要满足application-{profile}.yml的格式，其中{profile}对应你的环境标识，比如：

application-dev.yml：开发环境
application-test.yml：测试环境
application-prod.yml：生产环境
至于哪个具体的配置文件会被加载，需要在application.yml文件中通过spring.profiles.active属性来设置，其值对应{profile}值。

配置中最好不要出现中文，否则可能会报错

3.在resource目录中建一个包来存放Mybatis的.xml文件(写sql，详情见Mybatis)

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.example.springboot.mapper.UserMapper">


    <select id="Sel" resultType="com.example.springboot.pojo.User">
        select * from user where id = #{id}
    </select>

4.业务流程： 创建包controller，pojo，mapper，service

实体类：pojo.User

package com.example.springboot.pojo;

import javax.annotation.sql.DataSourceDefinition;
public class User {
    private Integer id;
    private String name;
    private Integer age;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

mapper.UserMapper

package com.example.springboot.mapper;

import com.example.springboot.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;
import java.util.Map;

@Repository
public interface UserMapper {
    User Sel(int id);
    List<User> getUserList();
    //查询
    User getUserById(int id);
    //增加
    int addUser(User user);
    //删除
    int deleteUser(int id);
    //修改
    int updateUser(User user);
    //万能Map
    int addUser2(Map<String,Object> map);
    //Map修改
    int updateMapUser(Map<String,Object> map);
}

service.UserService

package com.example.springboot.Service;

import com.example.springboot.mapper.UserMapper;
import com.example.springboot.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserService {
    @Autowired
    UserMapper userMapper;
    public User Sel(int id){
        return userMapper.Sel(id);
    }
}

controller.UserController

package com.example.springboot.controller;

import com.example.springboot.Service.UserService;
import com.example.springboot.mapper.UserMapper;
import com.example.springboot.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/testBoot")
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("getUser/{id}")
    public String GetUser(@PathVariable int id){
        return userService.Sel(id).toString();
    }
}

5.完成以上 在启动类中给出需要扫描的mapper路径（添加注解@MapperScan(“url”) ）

package com.example.springboot;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;


@MapperScan("com.example.springboot.mapper")//@MapperScan 用户扫描MyBatis的Mapper
@SpringBootApplication
public class SpringbootApplication {

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

}

**最后启动，浏览器输入地址：**http://localhost:8080/testBoot/getUser/1**