SpringBoot--整合Mybatis & 删除无效的文件和文件夹

Posted 2021-07-09 Z && Y

1. SpringBoot--整和Mybatis

mybatis-spring-boot-autoconfigure官方文档

maven仓库地址

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1.1 新建一个项目

删除无效的文件和文件夹

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1.2 建立数据库表

create database `mybatis`;
USE `mybatis`;
CREATE TABLE `user` (
                        `id` INT NOT NULL PRIMARY KEY,
                        `name` VARCHAR ( 30 ) DEFAULT NULL,
                        `pwd` VARCHAR ( 30 ) DEFAULT NULL
) ENGINE = INNODB DEFAULT CHARSET = utf8;

INSERT INTO USER (`id`, `name`, `pwd`) VALUES
(1,'余余', '123456'),
(2, '磊磊', '123456'),
(3, '骄骄', '123456');

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1.3 导入 MyBatis 所需要的依赖

pom.xml

<!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.4</version>
</dependency>

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1.4 配置数据库连接信息

application.properties

spring.datasource.username=root
spring.datasource.password=317525
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

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1.5 创建实体类，导入 Lombok

Lombok相关依赖
pom.xml

<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.20</version>
    <scope>provided</scope>
</dependency>

User.java

package com.tian.springbootmybatis.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * ClassName: User
 * Description: User的实体类
 *
 * @author Tianjiao
 * @date 2021/5/27 15:07
 */

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    private int id;
    private String name;
    private String pwd;
} 

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1.6 创建mapper目录以及对应的 Mapper 接口

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package com.tian.springbootmybatis.mapper;

import com.tian.springbootmybatis.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * ClassName: UserMapper
 * Description: User实体类的映射
 *
 * @author Tianjiao
 * @date 2021/5/27 15:17
 */

// @Mapper : 表示本类是一个 MyBatis 的 Mapper
@Mapper
@Repository
public interface UserMapper {

    // 获取所有部门信息
    List<User> getUsers();

    // 通过id获得部门
    User getUserById(Integer id);

}

也可以在SpringbootMybatisApplication扫描mapper

package com.tian.springbootmybatis;

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

@SpringBootApplication
// 扫描这个包下面的mapper
@MapperScan("com.tian.springbootmybatis.mapper")
public class SpringbootMybatisApplication {

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

}

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1.7 编写对应的Mapper映射文件

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.tian.springbootmybatis.mapper.UserMapper">

    <select id="getUsers" resultType="User">
        select *
        from mybatis.user;
    </select>

    <select id="getUserById" resultType="User">
        select *
        from mybatis.user
        where id = #{id};
    </select>

</mapper>

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1.8 整合Mybatis

application.properties

spring.datasource.username=root
spring.datasource.password=317525
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 整合mybatis
# 配置别名
mybatis.type-aliases-package=com.tian.springbootmybatis.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

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1.9 编写相应的controller

UserController.java

package com.tian.springbootmybatis.controller;

import com.tian.springbootmybatis.mapper.UserMapper;
import com.tian.springbootmybatis.pojo.User;
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;

/**
 * ClassName: UserController
 * Description:
 *
 * @author Tianjiao
 * @date 2021/5/27 17:16
 */
@RestController
public class UserController {
    final UserMapper userMapper;

    public UserController(UserMapper userMapper) {
        this.userMapper = userMapper;
    }

    @RequestMapping("/users")
    List<User> getUsers() {
        return userMapper.getUsers();
    }

    @RequestMapping("/userByID/{id}")
    User getUser(@PathVariable("id") int id) {
        return userMapper.getUserById(id);
    }
}

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2.0 运行结果

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