spring-boot 整合 mybatis

news2024/10/2 15:18:34

文章目录

Spring boot 整合Mybatis将数据返回到浏览器
- 1. 准备数据
- 2. 导入依赖
- 3. 配置数据库连接
- 4. 创建一个 pojo 包，创建User实体类
- 5. 创建一个mapper包，写一个UserMapper接口
- 6. 创建一个service包，写一个UserService接口。
- 7. 在 Service 包下创建一个子包，impl 包，然后 implements UserService 接口，同时将 UserService 接口和 userMapper 类的抽象方法 findById 实现。
- 8. 创建 controller 包
- 9. 查看结果

Spring boot 整合Mybatis将数据返回到浏览器

1. 准备数据

将数据放在本地的mysql数据库中

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 varchar(100) comment '年龄',
    gender varchar(100) 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');

在这里插入图片描述

2. 导入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <!--boot 工程的父工程，用于管理起步依赖的版本-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.3.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ithiema</groupId>
    <artifactId>springboot-demo2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-demo2</name>
    <description>springboot-demo2</description>
    <url/>
    <licenses>
        <license/>
    </licenses>
    <developers>
        <developer/>
    </developers>
    <scm>
        <connection/>
        <developerConnection/>
        <tag/>
        <url/>
    </scm>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <!--mysql驱动依赖-->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <version>8.0.33</version>
        </dependency>

<!--        &lt;!&ndash;MYSQL 驱动&ndash;&gt;-->
<!--        <dependency>-->
<!--            <groupId>mysql</groupId>-->
<!--            <artifactId>mysql-connector-java</artifactId>-->
<!--            <version>8.0.26</version>-->
<!--        </dependency>-->

        <!--mybatis 的起步依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>3.0.3</version>
        </dependency>


        <!--web起步依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

3. 配置数据库连接

在 application.properties 配置文件里改

spring.application.name=springboot-demo2
spring:
  datasource:
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/mybatis
    spring.datasource.username=root
    spring.datasource.password=p@ssw0rd

在这里插入图片描述

4. 创建一个 pojo 包，创建User实体类

里面四个属性,id，姓名，年龄，性别，手机号跟数据库表里的字段一一对应。

package com.ithiema.springbootdemo2.pojo;

public class User {
    
    private Integer id;
    private String name;
    private String age;
    private String gender;
    private String phone;

    public User() {
    }

    public User(Integer id, String name, String age, String 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 String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

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

5. 创建一个mapper包，写一个UserMapper接口

里面定义一个 findByid这个方法，传入一个 id 查询之后返回一个User对象。

package com.ithiema.springbootdemo2.mapper;

import com.ithiema.springbootdemo2.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

/**
 * ClassName: UserMapper
 * Packge: com.ithiema.springbootdemo2.mapper
 * Description:
 *
 * @Author: aex
 * @Create 2024/9/29 10:32
 * @Version 1.0
 */
@Mapper
public interface UserMapper {
    @Select("select * from mybatis.user where id = #{id}")
    public User findById(Integer id);
}

6. 创建一个service包，写一个UserService接口。

跟刚刚Mapper 包里一样的方法。

package com.ithiema.springbootdemo2.service;


import com.ithiema.springbootdemo2.pojo.User;

/**
 * ClassName: UserService
 * Packge: com.ithiema.springbootdemo2.service
 * Description:
 *
 * @Author: aex
 * @Create 2024/9/29 10:36
 * @Version 1.0
 */
public interface UserService{
    public User findById(Integer id);
}

7. 在 Service 包下创建一个子包，impl 包，然后 implements UserService 接口，同时将 UserService 接口和 userMapper 类的抽象方法 findById 实现。

package com.ithiema.springbootdemo2.service.impl;

import com.ithiema.springbootdemo2.mapper.UserMapper;
import com.ithiema.springbootdemo2.pojo.User;
import com.ithiema.springbootdemo2.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * ClassName: UserServiceImpl
 * Packge: com.ithiema.springbootdemo2.service.impl
 * Description:
 *
 * @Author: aex
 * @Create 2024/9/29 10:40
 * @Version 1.0
 */
@Service
public class UserServiceImpl implements UserService {  // 这个类是service 的容器，
    @Autowired
    private UserMapper userMapper;
    @Override
    public User findById(Integer id) {
        return userMapper.findById(id);
    }
}

8. 创建 controller 包

创建 UserController 类
package com.ithiema.springbootdemo2.controller;

import com.ithiema.springbootdemo2.pojo.User;
import com.ithiema.springbootdemo2.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.Mapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * ClassName: UserController
 * Packge: com.ithiema.springbootdemo2.controller
 * Description:
 *
 * @Author: aex
 * @Create 2024/9/29 10:52
 * @Version 1.0
 */
@RestController
public class UserController {
    @Autowired //注入属性
    private UserService userService;

    @RequestMapping("/findById")
    public User findById(Integer id){
        return userService.findById(id);
    }


}