SpringBoot整合MyBatis

一、前言

        随着时代的改变，Java技术发生了不少变迁，本文主要是用JDK21和最新版的MyBatis，整合的完整实例，可用于项目的初步搭建使用

 

二、在Spring网站下载demo

注意选择web mvc，和mybatis

 

三、mysql数据库中的表结构与项目结构

项目结构 

 

 

 四、pom.xml文件与application.properties文件

 pom.xml文件

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.4.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>21</java.version>
    </properties>
    <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>
            <version>3.0.4</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter-test</artifactId>
            <version>3.0.4</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.26</version>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>
</project>

 

application.properties文件

spring.application.name=demo

spring.mvc.static-path-pattern=/static/**
spring.resources.static-locations=classpath:/static/

spring.datasource.url=jdbc:mysql://localhost:3306/chapter05
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=123456

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

 

 

五、实体、dao层与mapper文件

实体

public class Book {

    private Integer id;

    private String name;

    private String author;

    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 == null ? null : name.trim();
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author == null ? null : author.trim();
    }


    @Override
    public String toString() {
        return "Book{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", author='" + author + '\'' +
                '}';
    }
}

 

dao层

mapper文件，我们这边使用mybatis-generator生成

@Mapper
public interface BookMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(Book record);

    int insertSelective(Book record);

    //@Select("SELECT * FROM book WHERE id = #{id}")
    Book selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(Book record);

    int updateByPrimaryKey(Book record);
}

 

 

六、controller层、service层

service层

@Service
public class BookService {

    @Autowired
    private BookMapper bookMapper;

    public Book getBook(){
        return bookMapper.selectByPrimaryKey(1);
    }
}

 

controller层

这里还是用传统的@Autowired注入，现在Spring官方提倡用构造器注入法[2]

@RestController
public class BookController {

    @Autowired
    private BookService bookService;

    //构造器注入法
//    public BookController(BookService bookService){
//        this.bookService = bookService;
//    }

    @RequestMapping("/getBook")
    public Book getBook(){
        Book book = bookService.getBook();
        return book;
    }


}

 

 

七、DemoApplication与测试结果

@SpringBootApplication
@MapperScan("com.example.demo.dao")
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

 

结果：

 

Reference

 [1] 王松，《Spring Boot + Vue 全栈开发实战》， 42-88页

 [2] wljslmz, 为什么Spring和IDEA不推荐使用@Autowired注解，有哪些替代方案, https://www.cnblogs.com/ryelqy/p/17794467.html