SpringBoot整合Mybaitis-使用mapper注解

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

1：准备数据库数据和配置数据源

#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

<dependency>                <groupId>org.mybatis.spring.bootgroupId>                <artifactId>mybatis-spring-boot-starterartifactId>                <version>1.3.2version>           dependency>                     <dependency>                <groupId>mysqlgroupId>                <artifactId>mysql-connector-javaartifactId>           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 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 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 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

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.slf4jgroupId>                <artifactId>slf4j-simpleartifactId>           dependency>

源码下载地址为：

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