springboot整合通用Mapper入门-编程知识

springboot整合通用Mapper入门

概述

通用 Mapper 是一个用于简化 MyBatis 操作的开发框架。它通过提供通用的 CRUD（创建、读取、更新、删除）方法，减少了开发者需要编写的重复代码。通用 Mapper 的一个著名的实现是 MyBatis Generator（MyBatis 代码生成器）。

查看这个接口的源码他继承了很多接口这些接口就已经帮助我们实现了增删改查

@RegisterMapper
public interface Mapper<T> extends BaseMapper<T>, ExampleMapper<T>, RowBoundsMapper<T>, Marker {
}

@RegisterMapper
public interface BaseMapper<T> extends BaseSelectMapper<T>, BaseInsertMapper<T>, BaseUpdateMapper<T>, BaseDeleteMapper<T> {
}

@RegisterMapper  这是查 可以看到继承了很多
public interface BaseSelectMapper<T> extends SelectOneMapper<T>, SelectMapper<T>, SelectAllMapper<T>, SelectCountMapper<T>, SelectByPrimaryKeyMapper<T>, ExistsWithPrimaryKeyMapper<T> {
}

第一步导入依赖

    <dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-tomcat</artifactId><scope>provided</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.2.18</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.28</version></dependency><!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jdbc --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId><version>3.0.6</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.33</version></dependency><!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter --><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>3.0.2</version></dependency><dependency><groupId>tk.mybatis</groupId><artifactId>mapper-spring-boot-starter</artifactId><version>2.1.5</version></dependency></dependencies>

第二步配置数据源和mybaits

server:port: 80
logging:level:com.example.springbootdemo1: debugorg.springframework: info
spring:datasource:url: jdbc:mysql://localhost:3306/db2username: 1111password: a118driver-class-name: com.mysql.jdbc.Driver
mybatis:type-aliases-package: com.example.springbootdemo1configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

第三步编写一个实体类

@Data
@Table(name = "user")
//根据数据库表自动映射
public class user {@Id//主键回填  主键一般都是自增的 当自增的时候自动回填到id上面
//    @KeySql(useGeneratedKeys = true)private String sno;@Column//如果符合驼峰规则 user_name --> userName 并且实体类变量和数据库变量一致可以不用这个注解private String name;private int point ;
}

第四步编写mapper接口继承通用mapper

import tk.mybatis.mapper.common.Mapper;public interface userMapper extends Mapper<user> {
}

第五步在springboot启动类那里加注解通用mapper扫描

@SpringBootApplication
@MapperScan("com.example.springbootdemo1.mapper")
public class Springbootdemo1Application {public static void main(String[] args) {SpringApplication.run(Springbootdemo1Application.class, args);}}

第六步编写服务类

@Service
public class userService {@Autowiredprivate userMapper userMapper1;@Transactionalpublic user queryById(String id){return userMapper1.selectByPrimaryKey(id);根据主键查询}
}

第七步测试

    @Autowiredprivate userService userService;@RequestMapping("/hello/{id}")public user hello1 (@PathVariable String id){return userService.queryById(id);}
}

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