Spring Boot 笔记 002 整合mybatis做数据库读取

概念

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。

mysql和mybatis依赖配置

    <!-- mysql驱动依赖   --><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</artifactId></dependency><!-- mybatis的起步依赖   --><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>3.0.0</version></dependency>

数据库创建

create database if not exists mybatis;use mybatis;create table user(id int unsigned primary key auto_increment comment 'ID',name varchar(100) comment '姓名',age tinyint unsigned comment '年龄',gender tinyint unsigned comment '性别, 1:男, 2:女',phone varchar(11) comment '手机号'
) comment '用户表';insert into user(id, name, age, gender, phone) VALUES (null,'白眉鹰王',55,'1','18800000000');
insert into user(id, name, age, gender, phone) VALUES (null,'金毛狮王',45,'1','18800000001');
insert into user(id, name, age, gender, phone) VALUES (null,'青翼蝠王',38,'1','18800000002');
insert into user(id, name, age, gender, phone) VALUES (null,'紫衫龙王',42,'2','18800000003');
insert into user(id, name, age, gender, phone) VALUES (null,'光明左使',37,'1','18800000004');
insert into user(id, name, age, gender, phone) VALUES (null,'光明右使',48,'1','18800000005');

数据库配置

spring:datasource:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/mybatisusername: rootpassword: root

创建实体类User

package com.geji.pojo;public class User {private Integer id;private String name;private Short age;private Short gender;private String phone;public User() {}public User(Integer id, String name, Short age, Short gender, String phone) {this.id = id;this.name = name;this.age = age;this.gender = gender;this.phone = phone;}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 Short getAge() {return age;}public void setAge(Short age) {this.age = age;}public Short getGender() {return gender;}public void setGender(Short gender) {this.gender = gender;}public String getPhone() {return phone;}public void setPhone(String phone) {this.phone = phone;}@Overridepublic String toString() {return "User{" +"id=" + id +", name='" + name + '\'' +", age=" + age +", gender=" + gender +", phone='" + phone + '\'' +'}';}
}

定义接口

package com.geji.mapper;import com.geji.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;@Mapper
public interface UserMapper {@Select("select * from user where id=#{id}")public User findById(Integer id);
}

package com.geji.service;import com.geji.pojo.User;public interface UserService {public User findById(Integer id);
}

创建查询类

package com.geji.service.impl;import com.geji.mapper.UserMapper;
import com.geji.pojo.User;
import com.geji.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class UserServiceImpl implements UserService {@Autowiredprivate UserMapper userMapper;@Overridepublic User findById(Integer id) {return userMapper.findById(id);}
}

编写controller

package com.geji.controller;import com.geji.pojo.User;
import com.geji.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class UserController {@Autowiredprivate UserService userService;@RequestMapping("/findById")public User findById(Integer id){return userService.findById(id);}
}