无法在嵌入式类中使用 Map<string,Object> 保存 Objectify 实体？

Question

我有一个嵌入实体，它的字段类型为 Map。

地图的所有键都是字符串类型。

下面是实体

@Entity
@Index
@Getter @Setter
public class NiftySurveys {
    @Id
    private Long id;
    private List<SurveyQuestions> questions;
    private Long createddate;
    private Long updatedDate;
}

@Getter @Setter
public class SurveyQuestions {
    private String label;
    private String code;
    private SurveyQuestionGroups questionGroup;
    private Map<String,Object> optionGroup;
}

我无法使用 optionGroup 保存实体。

从前端提交的示例实体

{
    "questions": [{
        "label": "jio",
        "code": null,
        "questionGroup": {
            "name": "Date Time",
            "value": "DATI"
        },
        "optionGroup": {
            "labels": [{
                "label": "Date / Time"
            }],
            "collectDateInfo": true,
            "collectTimeInfo": true,
            "dateFormat": "MM/DD/YYYY",
            "validationMessage": "Please Enter a Valid Date!"
        }
    }, {
        "code": null,
        "label": "Q2",
        "questionGroup": {
            "name": "Multiple Choice Questions",
            "value": "MCQ"
        },
        "optionGroup": {
            "name": "Agree - Disagree",
            "code": "AGDAG",
            "options": [{
                "label": "YES",
                "value": "Y"
            }, {
                "label": "NO",
                "value": "N"
            }]
        }
    }]
}

地图的所有键都是字符串。

错误信息：

exception: "com.googlecode.objectify.SaveException"
message: "Error saving com.nifty.niftyfeedbacks.domain.NiftySurveys@4ac88d5e: java.lang.IllegalStateException: Embedded Map keys must be of type String/Enum/Key<?> or field must specify @Stringify"

链接到堆栈跟踪 https://drive.google.com/file/d/1fqpPLiJutWLif5GnrlqLEZ6Wr_PdLdC-/view?usp=sharing

Answer 1

要了解@Stringify 的工作原理，请查看https://github.com/objectify/objectify/wiki/Entities#stringify：

In order to use non-String keys with Maps, you may specify the @Stringify annotation:

import com.googlecode.objectify.annotation.Entity;
import com.googlecode.objectify.annotation.Id;
import com.googlecode.objectify.annotation.Stringify;
import com.googlecode.objectify.stringifier.Stringifier;

class DateStringifier implements Stringifier<LocalDate> {
    @Override
    public String toString(LocalDate obj) {
        return obj.getString();
    }

    @Override
    public LocalDate fromString(String str) {
        return new LocalDate(str);
    }
}

@Entity
class Car {
    @Id Long id;
    @Stringify(DateStringifier.class)
    Map<LocalDate, ServiceRecord> serviceHistory = new HashMap<>();
}

之前的回复： 错误消息很清楚：您必须提供“字符串方式”来处理您的嵌入式实体。所以你应该在你的嵌入式实体中编写一个toString() 方法，或者酌情使用@Stringify 注释。

它似乎是 JSON，所以你尝试使用 @JsonUnwrapped ： @见https://stackoverflow.com/a/10077262/390462

class Item {
    private String title;

    @JsonProperty("date")
    private Date createdAt;

    // How to map this?
    @JsonUnwrapped
    private Author author;
}

您也可以通过一个很好的 JPA 教程来处理嵌入式对象：

1. https://examples.javacodegeeks.com/enterprise-java/jpa/jpa-embedded-embeddable-example/
2. https://www.logicbig.com/tutorials/java-ee-tutorial/jpa/embeddable-classes.html
3. https://www.tutorialspoint.com/ejb/ejb_embeddable_objects.htm

Answer 2

对复杂的对象图使用@Serialize注解。 From Objectify Docs

这解决了我的问题。

@Getter @Setter
public class SurveyQuestions implements Serializable{
    private static final long serialVersionUID = -6930992373082651231L;
    @Serialize
    private Map<String,Object> optionGroup;
    
    
}