【Java】Spring Boot（四）MyBatis

一.无配置文件注解版

1.添加相关 Maven 文件

<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>2.0.0</version>
+    </dependency>
+     <dependency>
+        <groupId>mysql</groupId>
+        <artifactId>mysql-connector-java</artifactId>
+    </dependency>
</dependencies>

2.application.properties 添加相关配置

mybatis.type-aliases-package=com.neo.model

spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

3.在启动类中添加对 mapper 包扫描@MapperScan

@SpringBootApplication
@MapperScan("com.neo.mapper")
public class MybatisAnnotationApplication {

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

或者直接在 Mapper 类上面添加注解@Mapper

4.开发Mapper

第三步是最关键的一块， Sql 生产都在这里

public interface UserMapper {

    @Select("SELECT * FROM users")
    @Results({
        @Result(property = "userSex",  column = "user_sex", javaType = UserSexEnum.class),
        @Result(property = "nickName", column = "nick_name")
    })
    List<UserEntity> getAll();

    @Select("SELECT * FROM users WHERE id = #{id}")
    @Results({
        @Result(property = "userSex",  column = "user_sex", javaType = UserSexEnum.class),
        @Result(property = "nickName", column = "nick_name")
    })
    UserEntity getOne(Long id);

    @Insert("INSERT INTO users(userName,passWord,user_sex) VALUES(#{userName}, #{passWord}, #{userSex})")
    void insert(UserEntity user);

    @Update("UPDATE users SET userName=#{userName},nick_name=#{nickName} WHERE id =#{id}")
    void update(UserEntity user);

    @Delete("DELETE FROM users WHERE id =#{id}")
    void delete(Long id);

}

为了更接近生产我特地将 user_sex、nick_name 两个属性在数据库加了下划线和实体类属性名不一致，另外 user_sex 使用了枚举

二.参考链接

1.原文链接：https://www.cnblogs.com/ityouknow/p/6037431.html