Spring Boot入门教程2-1、使用Spring Boot+MyBatis访问数据库（CURD）注解版

时间：2022-07-01 12:36:49

一、前言

  • 什么是MyBatis？
    MyBatis是目前Java平台最为流行的ORM框架
    https://baike.baidu.com/item/MyBatis/2824918

  • 本篇开发环境
    1、操作系统： Windows 10 X64
    2、Java SDK： jdk-8u141
    3、Maven：3.5
    4、IDE：IntelliJ IDEA 2017
    5、Spring Boot：1.5.6

本项目构建基于：https://ken.io/note/springboot-course-basic-helloworld

二、Spring Boot整合MyBatis

  • 引入核心依赖
package 说明
mybatis-spring-boot-starter MyBatis核心for Spring Boot
mysql-connector-java 用于连接MySQL

pom.xml文件：

<parent>

    <groupId>org.springframework.boot</groupId>

    <artifactId>spring-boot-starter-parent</artifactId>

    <version>1.5.6.RELEASE</version>

</parent>

<dependencies>

    <dependency>

      <groupId>org.springframework.boot</groupId>

      <artifactId>spring-boot-starter-web</artifactId>

    </dependency>

    <dependency>

      <groupId>org.mybatis.spring.boot</groupId>

      <artifactId>mybatis-spring-boot-starter</artifactId>

    </dependency>

    <dependency>

      <groupId>mysql</groupId>

      <artifactId>mysql-connector-java</artifactId>

      <version>5.1.38</version>

    </dependency>

    <dependency>

      <groupId>junit</groupId>

      <artifactId>junit</artifactId>

      <version>3.8.1</version>

      <scope>test</scope>

    </dependency>

</dependencies>
  • 配置数据库连接

在配置文件：application.yml中增加以下配置：

spring:

  datasource:

    driver-class-name: com.mysql.jdbc.Driver

    url: jdbc:mysql://localhost:3306/course?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8

    username: mysql

    password: password

数据库自行创建MySQL下载地址：https://dev.mysql.com/downloads/

  • Package创建
Package 说明
io.ken.springboot.course.model 用于存放实体
io.ken.springboot.course.dao 用于存放数据访问映射*mapper
  • user表&实体创建

1、user表创建脚本

DROP TABLE IF EXISTS `user`;

CREATE TABLE `user` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `name` varchar(255) DEFAULT NULL,

  `age` int(11) DEFAULT NULL,

  `hobby` varchar(500) DEFAULT NULL,

  PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2、user实体

package io.ken.springboot.course.model;

public class User {

    private int id;

    private String name;

    private int age;

    private String hobby;

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public int getAge() {

        return age;

    }

    public void setAge(int age) {

        this.age = age;

    }

    public String getHobby() {

        return hobby;

    }

    public void setHobby(String hobby) {

        this.hobby = hobby;

    }

}

getger和setter可以选中类名之后使用快捷键Alt+Insert生成

  • 创建UserMapper，用于User数据库操作映射
package io.ken.springboot.course.dao;

import io.ken.springboot.course.model.User;

import org.apache.ibatis.annotations.*;

import java.util.List;

@Mapper

public interface UserMapper {

    @Select("SELECT * FROM user WHERE id = #{id}")

    User queryById(@Param("id") int id);

    @Select("SELECT * FROM user")

    List<User> queryAll();

    @Insert({"INSERT INTO user(name,age,hobby) VALUES(#{name},#{age},#{hobby})"})

    int add(User user);

    @Delete("DELETE FROM user WHERE id = #{id}")

    int delById(int id);

    @Update("UPDATE user SET name=#{name},age=#{age},hobby=#{hobby} WHERE id = #{id}")

    int updateById(User user);

}
  • 创建UserController并提供API
package io.ken.springboot.course.controller;

import io.ken.springboot.course.dao.UserMapper;

import io.ken.springboot.course.model.User;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

@Controller

@RequestMapping("/user")

public class UserController {

    @Autowired

    UserMapper userMapper;

    @RequestMapping("/querybyid")

    @ResponseBody

    User queryById(int id) {

        return userMapper.queryById(id);

    }

    @RequestMapping("/queryall")

    @ResponseBody

    List<User> queryAll() {

        return userMapper.queryAll();

    }

    @RequestMapping("/add")

    @ResponseBody

    String add(User user) {

        return userMapper.add(user) == 1 ? "success" : "failed";

    }

    @RequestMapping("/updatebyid")

    @ResponseBody

    String updateById(User user) {

        return userMapper.updateById(user) == 1 ? "success" : "failed";

    }

    @RequestMapping("/delbyid")

    @ResponseBody

    String delById(int id) {

        return userMapper.delById(id) == 1 ? "success" : "failed";

    }

}
  • API测试
API 示例
添加用户 /user/add?name=tom&age=1&hobby=football
更新用户 /user/updatebyid?name=ken&age=18&hobby=coding&id=1
查询指定用户 /user/querybyid?id=1
查询所有用户 /user/queryall
删除指定用户 /user/delbyid?id=2

本文代码示例：https://github.com/ken-io/springboot-course/tree/master/chapter-02-01

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