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Java后端接口编写流程
Java后端接口编写流程，更具业务逻辑编写Java后端接口，提供给前端访问
实现逻辑流程
- POJO：实体类编写
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
@TableName("merchant_mcc")
public class MerchantMcc {
/**
* null | merchant_mcc.id | @mbg.generated
*/
@ApiModelProperty("null")
@TableId
private Long id;
/**
* MCC字段Code | merchant_mcc.code | @mbg.generated
*/
@ApiModelProperty("MCC字段Code")
private String code;
/**
* MCC字段Description | merchant_mcc.description | @mbg.generated
*/
@ApiModelProperty("MCC字段Description")
private String description;
}实体类字段的工具类编写：字段常量编写
package com.wei.gen.po;
public class MerchantMccCol {
public static final String ID = "id";
public static final String CODE = "code";
public static final String DESCRIPTION = "description";
}
- DAO：数据库访问层编写
public interface MerchantMccRepo extends IService<MerchantMcc> {
/**
* MCC 根据Code查询Description
*
* @param queryWrapper
* @return
*/
MerchantMcc selectOne(QueryWrapper<MerchantMcc> queryWrapper);
}
- 实现类Impl编写
@Slf4j
@Repository
public class MerchantMccRepoImpl extends ServiceImpl<MerchantMccMapper, MerchantMcc> implements MerchantMccRepo {
private final MerchantMccMapper merchantMccMapper;
public MerchantMccRepoImpl(MerchantMccMapper merchantMccMapper) {
this.merchantMccMapper = merchantMccMapper;
}
@Override
public MerchantMcc selectOne(QueryWrapper<MerchantMcc> queryWrapper) {
return merchantMccMapper.selectOne(queryWrapper);
}
}Mapper编写：实现对数据库的操作
@Mapper
public interface MerchantMccMapper extends BaseMapper<MerchantMcc> {
/**
* This method was generated by MyBatis Generator.
* This method corresponds to the database table merchant_mcc
*
* @mbg.generated
*/
MerchantMcc selectByPrimaryKey(Long id);
}Mapper.xml编写：自定义编写SQL语句，业务逻辑
id属性：指定Mapper.xml文件中的SQL语句对应的Java接口方法名称，这个方法将会执行相应的SQL语句，并返回执行结果
type属性：指定Mapper.xml文件中的Java类对应的实体类名称，这个实体类包含了与SQL语句相对应的属性和方法，用于将执行结果转换为Java对象
<?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.wei.gen.dao.MerchantMccMapper">
</mapper>Service层：业务逻辑编写
/**
* MCC 根据Code查询Description
*/
public String getDescriptionByCode(String code) {
if (code == null || code.isEmpty()){
throw new ManageException("Code不能为空");
}
MerchantMcc merchantMcc = merchantMccRepo.selectOne(new QueryWrapper<MerchantMcc>().eq("code", code));
if (merchantMcc == null) {
throw new ManageException("Code不存在");
}
return merchantMcc.getDescription();
}Controller层：接口编写
@RestController
@Slf4j
@RequestMapping("common")
public class SystemCommonEndpoint {
@Resource
private CommonService commonService;
/**
* MCC 根据Code查询Description
*/
@GetMapping("/search")
@ApiOperation("MCC根据Code查询Description")
public Result<String> searchDescription(@RequestParam("code") String code) {
String description = commonService.getDescriptionByCode(code);
return Result.succ(description);
}
}🌼 结语：创作不易，如果觉得博主的文章赏心悦目，还请——
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