SpringBoot MyBatis简单快速入门例子

SpringBoot MyBatis简单快速入门例子

目录一、MyBatis简介二、MyBatis使用步骤

一、MyBatis简介

MyBatis 是一款优秀的持久层框架，它支持自定义 SQL、存储过程以及高级映射。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。MyBatis 可以通过简单的 XML 或注解来配置和映射原始类型、接口和 java POJO（Plain Old Java Objects，普通老式 Java 对象）为数据库中的记录。

二、MyBatis使用步骤

1、MyBatis工程总体目录结构

2、创建简单的SpringBoot工程

3、添加MyBatis依赖

mysql

mysql-connector-java

5.1.32

org.mybatis

mybatis

3.4.6

4、在数据库创建USER表

CREATE TABLE `user` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`username` varchar(20) NOT NULL DEFAULT '' COMMENT '用户名',

`password` varchar(50) NOT NULL DEFAULT '' COMMENT '密码',

PRIMARY KEY (`id`) USING BTREE

) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 ROW_FORMAT=DYNAMIC;

5、在application.properties配置数据库连接信息

#数据库相关配置

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useSSL=false&characterEncoding=utf8&allowMultiQueries=true&serverTimezone=Asia/Shanghai&useAffectedRows=true

spring.datasource.username=root

spring.datasource.password=QQ796413

#mybaits配置

#mapper加载路径

mybatis.mapper-locations= classpath:mapper/*.xml

#实体包位置

mybatis.type-aliases-package= com.example.mybatisdemo.entity

#myatbis配置文件

mybatis.config-location= classpath:mybatis-config.xml

6、创建USER表对应的实体类

package com.example.mybatisdemo.entity;

public class User {

private int id;

private String username;

private String password;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

@Override

public String toString() {

return "User{" +

"id=" + id +

", username='" + username + '\'' +

", password='" + password + '\'' +

'}';

}

7、在mapper/UserMapper创建UserMapper.java

package com.example.mybatisdemo.mapper;

import com.example.mybatisdemo.entity.User;

import org.apache.ibatis.annotations.Mapper;

@Mapper

public interface UserMapper{

User findUserById(Integer id);

}

8、在service/UserService新建UserService.java

package com.example.mybatisdemo.service;

import com.example.mybatisdemo.entity.User;

public interface UserService {

User findUserById(Integer id);

}

9、在service/impl/UserServiceImpl 创建UserServiceImpl.java

package com.example.mybatisdemo.service.impl;

import com.example.mybatisdemo.entity.User;

import com.example.mybatisdemo.mapper.UserMapper;

import com.example.mybatisdemo.service.UserService;

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

import org.springframework.stereotype.Service;

@Service

public class UserServiceImpl implements UserService {

@Autowired

private UserMapper userMapper;

@Override

public User findUserById(Integer id) {

return userMapper.findUserById(id);

}

}

10、在resources下新建mybatis-conf.xml

PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-config.dtd">

11、在resources下mapper文件下创建UserMapper.xml

select

id,

username,

password

from

user

where

id= #{id,jdbcType=INTEGER}

12、创建UserController.java

package com.example.mybatisdemo.controller;

import com.example.mybatisdemo.entity.User;

import com.example.mybatisdemo.service.UserService;

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

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

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

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

@RestController

public class UserController {

@Autowired

UserService userService;

@GetMapping("/findUserById")

public User findUserById(@RequestParam Integer id){

return userService.findUserById(1);

}

}

13、测试

工程可以去我的资源-

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