Spring Boot Tutorial: Building a Rental Service with MyBatis Integration

Spring Boot Concept

Spring Boot is a collection of libraries that simplifies the creation of stand‑alone Spring applications, provides an embedded Tomcat server, reduces Maven configuration, offers auto‑configuration, and includes production‑ready features such as metrics and health checks.

Setting Up Spring Boot

1. Generate a project template at https://start.spring.io/ and import it into IntelliJ IDEA.

2. Create a controller (see image).

3. Run the project by adding @ComponentScan and executing the application. After the compilation succeeds, open a browser and visit http://localhost:8080/index to see the result.

Integrating MyBatis

MyBatis is a powerful persistence framework that supports custom SQL, stored procedures, and advanced mappings.

In pom.xml add the following dependencies:

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.1.1</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.30</version>
</dependency>

Create the database and users table:

use zuche;
CREATE TABLE `users` (
    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
    `username` varchar(255) NOT NULL,
    `age` int(10) NOT NULL,
    `phone` bigint NOT NULL,
    `email` varchar(255) NOT NULL,
    PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO users VALUES (1,'赵',23,158,'[email protected]');
INSERT INTO users VALUES (2,'钱',27,136,'[email protected]');
INSERT INTO users VALUES (3,'孙',31,159,'[email protected]');
INSERT INTO users VALUES (4,'李',35,130,'[email protected]');

Domain Model

Create the User POJO:

package com.athm.pojo;

public class User {
    private int id;
    private String username;
    private Integer age;
    private Integer phone;
    private String email;
    // getters and setters omitted for brevity
}

Mapper Interface

Define UserMapper with a MyBatis @Select statement:

package com.athm.dao;

import com.athm.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import java.util.List;

@Mapper
public interface UserMapper {
    @Select("SELECT id,username,age,phone,email FROM USERS WHERE AGE=#{age}")
    List<User> getUser(int age);
}

Service Layer

Define the service interface and its implementation:

package com.athm.service;

import com.athm.pojo.User;
import java.util.List;

public interface UserService {
    List<User> getUser(int age);
}

package com.athm.service;

import com.athm.dao.UserMapper;
import com.athm.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    UserMapper userMapper;

    @Override
    public List<User> getUser(int age) {
        return userMapper.getUser(age);
    }
}

Controller

Expose two endpoints: a REST API returning users by age and a simple map endpoint.

package com.athm.controller;

import com.athm.pojo.User;
import com.athm.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
public class IndexController {
    @Autowired
    UserService userService;

    @GetMapping("/show")
    public List<User> getUser(int age) {
        return userService.getUser(age);
    }

    @RequestMapping("/index")
    public Map<String, String> index() {
        Map<String, String> map = new HashMap<>();
        map.put("北京", "北方城市");
        map.put("深圳", "南方城市");
        return map;
    }
}

Application Class

Configure component scanning and MyBatis mapper scanning:

package com.athm.zuche;

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

@SpringBootApplication
@ComponentScan(basePackages = {"com.athm.controller", "com.athm.service"})
@MapperScan(basePackages = {"com.athm.dao"})
public class ZucheApplication {
    public static void main(String[] args) {
        SpringApplication.run(ZucheApplication.class, args);
    }
}

Configuration

Add the following properties to application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/zuche
spring.datasource.username=toutou
spring.datasource.password=*******
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

Running the Application

Start the Spring Boot application, then open a browser and navigate to http://localhost:8080/show?age=30 to retrieve users older than 30, or visit http://localhost:8080/index to see the map response.

GitHub Repository

The complete source code is available at https://github.com/toutouge/javademo/tree/master/zuche_test/zuche .

Conclusion

System failures are often unpredictable; therefore, designers must anticipate risks and implement safeguards to ensure reliability.