文章简介
本文介绍了springboot+mybatis实现数据库操作的两种实现方式，经测试均可运行使用。整体而言注解更加简便，但面对一些复杂查询，可能需要使用到注解方式。
注解方式
pom依赖：
<dependencies><!--连接数据库--><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>1.3.1</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>6.0.6</version></dependency></dependencies>
application.yaml配置文件
spring:datasource:url: jdbc:mysql://localhost:3306/mmall_learning?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456driver-class-name: com.mysql.cj.jdbc.Driver #com.mysql.cj.jdbc.Driver
Controller层
@RestController
public class UserController {@Autowiredprivate UserService userService;@RequestMapping(value = "/get_user", method = RequestMethod.GET)public ResponseEntity<User> getUser(@RequestParam(value = "id") String userId) {User user = userService.getUser(userId);return ResponseEntity.status(HttpStatus.OK).body(user);}
}
Service层
@Service
public class UserService {@Autowiredprivate UserMapper userMapper;public User getUser(String userId) {User user = userMapper.findById(userId);return user;}}
Dao层
@Mapper
public interface UserMapper {@Select("SELECT * FROM mmall_user WHERE ID = #{id}")User findById(@Param("id") String id);
}
实体类
@Data
public class User {private Integer id;private String username;private String password;private String email;
}
评析：注解方式非常简便，没有额外的配置工作。
xml方式
xml方式相对来说会需要配置一些路径参数，如果各位想通过这种方式实现数据库操作，可以参照以下目录结构和对应路径配置来实现。
目录结构
pom依赖：
<dependencies><!--连接数据库--><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>1.3.1</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>6.0.6</version></dependency><!-- Mybatis核心 仅xml方式需要加入该依赖，注解方式不需要 --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.7</version></dependency></dependencies>
application.yaml配置文件：
spring:datasource:url: jdbc:mysql://localhost:3306/mmall_learning?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456driver-class-name: com.mysql.cj.jdbc.Driver #com.mysql.cj.jdbc.Driver# 配置Mybatis文件位置，告诉Spring Boot你需要扫描的位置
mybatis:mapper-locations: classpath:com.example.demo.dao/*.xml
UserMapper.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demo.mmall.dao.UserMapper"><select id="findById" parameterType="int" resultType="com.example.demo.mmall.bean.User">SELECT * FROM mmall_user WHERE id = #{id}</select>
</mapper>
Controller层
@RestController
public class UserController {@Autowiredprivate UserService userService;@RequestMapping(value = "/get_user", method = RequestMethod.GET)public ResponseEntity<User> getUser(@RequestParam(value = "id") String userId) {User user = userService.getUser(userId);return ResponseEntity.status(HttpStatus.OK).body(user);}
}
Service层
@Service
public class UserService {@Autowiredprivate UserMapper userMapper;public User getUser(String userId) {User user = userMapper.findById(Integer.valueOf(userId));return user;}}
Dao层
@Mapper
public interface UserMapper {User findById(@Param("id") Integer id);
}
实体类
@Data
public class User {private Integer id;private String username;private String password;private String email;
}
评析：XML方式需要做些额外的配置工作，包括新建xml映射文件、在application.yaml中配置扫描路径等。但总体来说，比原来spring+mybatis使用xml方式实现数据库操作的配置已经简便不少了。
测试结果
以上两种方式测试结果均如下所示，可以正常查询到所需数据。
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