[Java知识库]注解版MyBatis操作

1.创建项目的时候要勾选好mybatis

?2. 创建mapper/ProviderMapper

package com.cc.springboot.mapper;

import com.cc.springboot.entities.Provider;
import org.apache.ibatis.annotations.*;

//使用mybatis注解版本
@Mapper   //指定这是操作数据的mapper
public interface ProviderMapper {

//   查询某一项
    @Select("select * from provider where pid=#{pid}")
    Provider getProviderByPid(Integer pid);

//    插入
//    useGeneratedKeys 是否使用自增主键，keyProperty指定实体类中的那个属性封装主键值
    @Options(useGeneratedKeys = true,keyProperty = "pid")
    @Insert("insert into provider(providerName) values (#{providerName})")
    int addProvider(Provider provider);

//    删除
    @Delete("delete from provider where pid=#{pid}")
    int deleteProvider(Integer pid);

//    更新
    @Update("update provider set providerName=#{providerName} where pid=#{pid}")
    int updateProvider(Provider provider);
}

知识点：1.数据库的操作

? ? ? ? ? ? ? ?2.插入时封装主键值，回显pid,没有的话，你回显的provider中pid显示null

3.controller/ProviderController使用

package com.cc.springboot.controller;

import com.cc.springboot.entities.Provider;
import com.cc.springboot.mapper.ProviderMapper;
import org.apache.ibatis.annotations.Options;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ProviderController {
    @Autowired
    ProviderMapper providerMapper;

    @GetMapping("/provider/{pid}")
    public Provider getProvider(@PathVariable("pid") Integer pid){
        Provider provider = providerMapper.getProviderByPid(pid);
        return provider;
    }


    @GetMapping("/provider")
    public Provider insertProvider(Provider provider){
        providerMapper.addProvider(provider);
       return provider;
    }


}

? 知识点? @RestController

4.数据库中是'-',实体类中是驼峰命名，导致显示不出相关数据

?config/MyBatisConfig

package com.cc.springboot.config;

import org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

//mybatis的注解版本相关配置
@Configuration
public class MyBatisConfig {

    @Bean
    public ConfigurationCustomizer configurationCustomizer(){

      return new ConfigurationCustomizer(){
            @Override
            public void customize(org.apache.ibatis.session.Configuration configuration) {
//                开启驼峰命名方式
                configuration.setMapUnderscoreToCamelCase(true);
            }
        };
    }
}

5.运行的应用程序

package com.cc.springboot;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

//会自动装配指定包下面所有Mapper,省的在每个Mapper上面写@Mapper
@MapperScan("com.cc.springboot.mapper")
@SpringBootApplication
public class Springboot08DataMybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(Springboot08DataMybatisApplication.class, args);
    }

}

//会自动装配指定包下面所有Mapper,省的在每个Mapper上面写@Mapper
@MapperScan("com.cc.springboot.mapper")