Question

I have a Javascript application that uses Java as a backend with Hibernate, Spring and MySQL DB . When reading data everything works fine and as expected but when trying to edit it on the client side I can see strange behaviour. Even though my server request looks like this :

{"data":{"Draggable":true,"Resizable":true,"StartDate":"2012-09-13T18:00:00+02:00","EndDate":"2012-09-14T04:00:00+02:00","Cls":"","Name":"Secret task","Id":10,"ResourceId":15}}

server responds with :

{"data":[{"Name":"Secret task","Id":10,"StartDate":"2012-09-13T18:00:00+02:00","EndDate":"2012-09-14T04:00:00+02:00","ResourceId":15,"Resizable":null,"Draggable":null,"Cls":""}]}

in which the boolean properties are nulled. I’ve tried ignoring the setter for this field but without any luck. I also had to remove nullable=false as with this included I was getting an error :

org.springframework.dao.DataIntegrityViolationException: not-null property references a null or transient value: model.Event.draggable; nested exception is org.hibernate.PropertyValueException: not-null property references a null or transient value: model.Event.draggable

This is my MySQL table definition :

CREATE TABLE IF NOT EXISTS `events` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `Name` varchar(255) DEFAULT NULL,
  `StartDate` varchar(50) DEFAULT NULL,
  `EndDate` varchar(50) DEFAULT NULL,
  `ResourceId` int(11) DEFAULT NULL,
  `Resizable` tinyint(1) DEFAULT NULL,
  `Draggable` tinyint(1) DEFAULT NULL,
  `Cls` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`Id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=12 ;

And this is the model code :

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

import org.codehaus.jackson.annotate.JsonAutoDetect;
import org.codehaus.jackson.annotate.JsonProperty;
import org.codehaus.jackson.annotate.JsonIgnoreProperties;
import org.codehaus.jackson.annotate.JsonIgnore;

@JsonAutoDetect
@JsonIgnoreProperties(ignoreUnknown = true)
@Entity
@Table(name="events")
public class Event {

    @Id
    @GeneratedValue
    @Column(name="Id")
    private int id;

    @Column(name="Name", nullable=false)
    private String name;

    @Column(name="StartDate", nullable=false)
    private String startDate;

    @Column(name="EndDate", nullable=false)
    private String endDate;

    @Column(name="ResourceId", nullable=false)
    private int resourceId;

    @Column(name="Resizable")
    private Boolean resizable;

    @Column(name="Draggable")
    private Boolean draggable;

    @Column(name="Cls", nullable=false)
    private String cls;

    @JsonProperty("Id")
    public int getId() {
        return id;
    }

    @JsonProperty("Id")
    public void setId(int id) {
        this.id = id;
    }

    @JsonProperty("Name")
    public String getName() {
        return name;
    }

    @JsonProperty("Name")
    public void setName(String name) {
        this.name = name;
    }

    @JsonProperty("StartDate")
    public String getStartDate() {
        return startDate;
    }

    @JsonProperty("StartDate")
    public void setStartDate(String start) {
        this.startDate = start;
    }

    @JsonProperty("EndDate")
    public String getEndDate() {
        return endDate;
    }

    @JsonProperty("EndDate")
    public void setEndDate(String end) {
        this.endDate = end;
    }

    @JsonProperty("ResourceId")
    public int getResourceId() {
        return resourceId;
    }

    @JsonProperty("ResourceId")
    public void setResourceId(int id) {
        this.resourceId = id;
    }

    @JsonProperty("Resizable")
    public Boolean getResizable() {
        return resizable;
    }

    @JsonIgnore
    public void setResizable(Boolean resizable) {
        this.resizable = resizable;
    }

    @JsonProperty("Draggable")
    public Boolean getDraggable() {
        return draggable;
    }

    @JsonIgnore
    public void setDraggable(Boolean draggable) {
        this.draggable = draggable;
    }

    @JsonProperty("Cls")
    public String getCls() {
        return cls;
    }

    @JsonProperty("Cls")
    public void setCls(String cls) {
        this.cls = cls;
    }
}

Is there anything I can do to prevent this behaviour ?

Answer 1

You are explicitly telling Jackson to ignore the two properties you mentioned, when deserializing your object from its JSON representation. This:

@JsonIgnore
public void setDraggable(Boolean draggable) {
    this.draggable = draggable;
}

@JsonIgnore
public void setResizable(Boolean resizable) {
    this.resizable = resizable;
}

Basically means, ignore these properties when deserializing from my JSON data. So, consequently when you save your object those properties are null in the database.