JPA瞬态注释和JSON

Question

这是有关JPA Transient批注的以下问题的后续解答 为什么JPA具有@Transient批注？

我有一个我不想保留的瞬态变量，并用瞬态注释标记。但是，当我想从我的rest控制器生成JSON时，此瞬态变量在输出的JSON中不可用。

POJO PublicationVO直截了当，没有花哨的属性，只有一些具有getter和setter和1个瞬态变量的私有属性（已保留）。

@RequestMapping(value = { "{publicationId}"}, method = RequestMethod.GET, produces = "application/json")
@ResponseBody public PublicationVO getPublicationDetailsJSON(@PathVariable(value = "publicationId") Integer publicationId) {
    LOG.info("Entered getPublicationDetailsJSON - publicationId: " + publicationId);

    //Call method to get the publicationVO based on publicationId
    PublicationVO publicationVO = publicationServices.getPublicationByIdForRestCalls(publicationId);       
    LOG.info("publicationVO:{}", publicationVO);

    LOG.info("Exiting getPublicationDetailsJSON");
    return publicationVO;
}

The PublicationVO is as follows

    package com.trinity.domain.dao;

import java.util.Calendar;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.persistence.Transient;

import com.fasterxml.jackson.annotation.JsonInclude;

@Entity
@Table(name = "publication")
public class PublicationVO {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;    
    @Column(name = "publicationName", unique = false, nullable = false, length = 200)
    private String publicationName;
    @Column(name = "publicationSource", unique = false, nullable = false, length = 45)
    private String publicationSource;

    @Column(name = "dateAdded", unique = false, nullable = false)
    private Calendar dateAdded;

    @Transient
    private float percentageProcessed;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getPublicationName() {
        return publicationName;
    }

    public void setPublicationName(String publicationName) {
        this.publicationName = publicationName;
    }

    public String getPublicationSource() {
        return publicationSource;
    }

    public void setPublicationSource(String publicationSource) {
        this.publicationSource = publicationSource;
    }

    public Calendar getDateAdded() {
        return dateAdded;
    }

    public void setDateAdded(Calendar dateAdded) {
        this.dateAdded = dateAdded;
    }

    public float getPercentageProcessed() {
        return percentageProcessed;
    }

    public void setPercentageProcessed(float percentageProcessed) {
        this.percentageProcessed = percentageProcessed;
    }

    @Override
    public String toString() {
        return "PublicationVO [id=" + id + ", publicationName=" + publicationName + ", publicationSource=" + publicationSource + ", dateAdded=" + dateAdded
                + ", percentageProcessed=" + percentageProcessed + "]";
    }
}

当我在日志中看到publicationVO的调试语句时，输出中将包含瞬态变量，但在客户端代码中，json响应中将不包含瞬态变量。

Answer 1

我只是添加了JsonSerialize和JsonDeserialize批注。

@Transient
@JsonSerialize
@JsonDeserialize
private String myField;