SpringBoot整合Mybaitis-使用mapper注解

末蓝、 2022-05-12 09:52 266阅读 0赞

上一篇博文已经详细介绍了SpringBoot环境搭建过程，这一节介绍一下SpringBoot整合Mybatis。

SpringBoot整合Mybatis

方式1：mapper使用注解

项目结构

70

1：准备数据库数据和配置数据源

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#数据源必填项

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

spring.datasource.url = jdbc:mysql://localhost:3306/study?useUnicode=true&characterEncoding=utf-8

spring.datasource.username = root

spring.datasource.password = 123456

 

#选填

# Number of ms to wait before throwing an exception if no connection is available.

spring.datasource.tomcat.max-wait=10000

# Maximum number of active connections that can be allocated from this pool at the same time.

spring.datasource.tomcat.max-active=50

# Validate the connection before borrowing it from the pool.

spring.datasource.tomcat.test-on-borrow=true

2：加maven依赖







          <!— Spring-Mybatis —>

          <dependency>

               <groupId>org.mybatis.spring.boot</groupId>

               <artifactId>mybatis-spring-boot-starter</artifactId>

               <version>1.3.2</version>

          </dependency>

          <!— MySQL驱动 —>

          <dependency>

               <groupId>mysql</groupId>

               <artifactId>mysql-connector-java</artifactId>

          </dependency>

3：编写实体类







public class User implements Serializable {

 

     private static final long serialVersionUID = 1L;

 

     private int id;// id

 

     private String name;// 姓名

 

     private int age;// 年龄

 

     public int getId() {

          return id;

     }

 

     public void setId(int id) {

          this.id = id;

     }

 

     public String getName() {

          return name;

     }

 

     public void setName(String name) {

          this.name = name;

     }

 

     public int getAge() {

          return age;

     }

 

     public void setAge(int age) {

          this.age = age;

     }

 

     @Override

     public String toString() {

          return “User [id=” + id + “, name=” + name + “, age=” + age + “]”;

     }

 

}

4：编写mapper







import java.util.List;

 

import org.apache.ibatis.annotations.Mapper;

import org.apache.ibatis.annotations.Select;

 

import com.liujia.springdemo.entity.User;

 

//@Mapper 这里可以使用@Mapper注解，但是每个mapper都加注解比较麻烦，所以统一配置@MapperScan在扫描路径在application类中

public interface UserMapper {

 

    /*

      获取所有的user对象

     

      @return

     /

    @Select(“SELECT FROM user”)

    List<User> getAll();

}

5：编写service层







import java.util.List;

 

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

import org.springframework.stereotype.Service;

 

import com.liujia.springdemo.entity.User;

import com.liujia.springdemo.mapper.UserMapper;

 

@Service

public class UserService {

    @Autowired

    private UserMapper userMapper;

 

    public List<User> getAll() {

         return userMapper.getAll();

    };

}

6：编写Copntroller层







import java.util.List;

 

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

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

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

 

import com.liujia.springdemo.entity.User;

import com.liujia.springdemo.service.UserService;

 

@RestController

public class UserController {

 

     @Autowired

     private UserService userService;

 

     @RequestMapping(“/getallusers”)

     public List<User> getAllUsers() {

          return userService.getAll();    

     }

}

7：增加包扫描和运行程序







@SpringBootApplication

@MapperScan(basePackages = { “com.liujia.springdemo.mapper”})

public class Application {

 

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);

    }

 

    @Bean

    public CommandLineRunner commandLineRunner(ApplicationContext ctx) {

        return args -> {

            System.out.println(“Let’s inspect the beans provided by Spring Boot:”);

            String[] beanNames = ctx.getBeanDefinitionNames();

            Arrays.sort(beanNames);

            for (String beanName : beanNames) {

                System.out.println(beanName);

            }

        };

    }

}

运行结果

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参考文献

https://docs.spring.io/spring-boot/docs/2.0.5.RELEASE/reference/htmlsingle/#boot-features-using-jdbc-template

遇到问题

SLF4J: Failed to load class “org.slf4j.impl.StaticLoggerBinder”

解决办法

参见https://blog.csdn.net/liuxiangke0210/article/details/77892564

缺少jar包依赖







          <dependency>

               <groupId>org.slf4j</groupId>

               <artifactId>slf4j-simple</artifactId>

          </dependency>

源码下载地址为：

https://download.csdn.net/download/caoshangfeidie000/10670695

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