如何使用 Springboot 和 Hibernate 在 DTO 和 Aggentity 类中映射 Postgres JSON 数据类型

问题描述

我有一个 ResponseDto 类，如下所示:

I have a ResponseDto class which looks like as below:

public static class HealthGoalsHighlight {

    @ApiModelProperty(value = "Total number of eligible users")
    private Long totalEligibleUsers;
    @ApiModelProperty(value = "Total number of registered users")
    private Long totalRegisteredUsers;
    @ApiModelProperty(value = "Total number of users with atleast one goal count")
    private Long totalUsersWithGoal;
    @ApiModelProperty(value = "Top goal name selected by user")
    private String topGoal;
    @ApiModelProperty(value = "Bottom goal name selected by user")
    private String bottomGoal;
  }

此 DTO 是基于下表结构制作的:

This DTO was made based upon below table structure:

health_goals
(
  uid BIGSERIAL NOT NULL CONSTRAINT health_goals_pkey primary key,
  employer_key bigint not null,
  total_eligible_users bigint not null,
  total_registered_users bigint not null,
  total_users_with_goal bigint not null,
  top_goal_name varchar(255),
  bottom_goal_name varchar(255),
  created_ts TIMESTAMP NOT NULL DEFAULT NOW(),
  updated_ts TIMESTAMP NOT NULL DEFAULT NOW(),
  created_by varchar(255),
  updated_by varchar(255)
);

现在表结构已经改为如下:

Now the table structure has been changed to as below:

health_goals
(
  uid BIGSERIAL NOT NULL CONSTRAINT health_goals_pkey primary key,
  employer_key bigint not null,
  health_goals_metric_value json null,
  created_ts TIMESTAMP NOT NULL DEFAULT NOW(),
  updated_ts TIMESTAMP NOT NULL DEFAULT NOW(),
  created_by varchar(255),
  updated_by varchar(255)
);

现在基本上所有这些列，例如 total_eligible_users、total_registered_users、total_users_with_goal、top_goal_name、bottom_goal_name 将合并为单列health_goals_metric_value 作为 JSON 数据类型.

Basically now all these columns like total_eligible_users, total_registered_users, total_users_with_goal, top_goal_name, bottom_goal_name wil be consolidated to single columnhealth_goals_metric_value as a JSON data type.

如何为 JSON 数据类型列编写响应 DTO.还有我的 AggMapper 类需要做哪些改动.

How can I write the response DTO for JSON data type column. Also what changes needs to be done in my AggMapper class.

推荐答案

嗯，一种方法是使用转换器函数.您可以使用转换器函数获取相同格式的值.

Well one way is by using converter function. You can use the converter function to get values in same format.

在您的列定义中更改您的 orm.xml 类似于下面的内容

Change your orm.xml something like below on your column definition

<basic name="healthGoalsMetricValue">
                <column name="health_goals_metric_value" nullable="true"/>
                <convert converter="path.to.your.HealthGoalsMetricValueConverter"/>
            </basic>

或者如果你有java文件

Or if you have java file

代理将有以下条目

  @Convert(converter = HealthGoalsMetricValueConverter.class)
    private HealthGoalsHighlight healthGoalsHighlight ;

和你的类 HealthGoalsMetricValue 看起来像

//////////////////评论后编辑转换器类

//////////////////Edited converter class after comments

       import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;
import java.io.IOException;

@Converter
public class HealthGoalsMetricValueConverter implements AttributeConverter<HealthGoalsMetricValue, String> {

private final ObjectMapper mapper = new ObjectMapper();

//And then override like that
@Override
        public String convertToDatabaseColumn(HealthGoalsHighlight healthGoalsMetricValue) {

            try {                
                json = mapper.writeValueAsString(healthGoalsMetricValue);
            } catch (JsonProcessingException exception) {
                throw new JsonProcessingException("Error occurred while object serialization", exception);
            }
            return json;
    }

 //And then override again
@Override
public HealthGoalsMetricValue  convertToEntityAttribute(String healthGoalsMetricValuestr ) {
    HealthGoalsMetricValue  healthGoalsMetricValue  = null;
    try {
        if (healthGoalsMetricValue != null) {
            healthGoalsMetricValue = mapper.readValue(healthGoalsMetricValuestr, HealthGoalsMetricValue.class);
        }
    } catch (Exception exception) {
        throw new Exception("Error occurred while object Deserialization", exception);
    }
    return healthGoalsMetricValue;
}

这一切都会为您完成工作.

This all will do the job for you.

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