JPA Entity, JSON serialization - json

Question

I have my JPA Entity class, AssetOrder. And I have defined a custom JSONSerializer for another entity called Product, which is used by AssetOrder entity internally to map the productID from the Product. As we can see the AssetOrder also has a JSONSerializer for formatting the Date objects.
The Date object JSON serialization works perfectly. However, I am not sure whether the JSONSerializer for the Product works perfectly. When I retrieve the AssetOrder objects from the JPA DAO and try to display on my client page, I get a response saying - Response contains invalid JSON data. I have enclosed the three java classes, AssetOrder.java, Product.java and JSONProductSerializer.java.
Please help, where I have done wrong.
Thanks.
//===================== AssetOrder.java ============================
package my.pkg;
import java.util.Date;
import javax.persistence.CascadeType;
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 com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
#JsonAutoDetect
#Entity
public class AssetOrder {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long orderId;
private String orderRequesterSignum;
private String orderOwnerSignum;
#JoinColumn(name = "productID")
#ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private Product product;
//private String productId;
private int duartion;
private String processInstanceUUID;
private Date orderDate;
private Date orderDeliveryDate;
private Date modifiedDate;
private String status;
private String comments;
public Long getOrderId() {
return orderId;
}
public void setOrderId(Long orderId) {
this.orderId = orderId;
}
public String getOrderRequesterSignum() {
return orderRequesterSignum;
}
public void setOrderRequesterSignum(String orderRequesterSignum) {
this.orderRequesterSignum = orderRequesterSignum;
}
public String getOrderOwnerSignum() {
return orderOwnerSignum;
}
public void setOrderOwnerSignum(String orderOwnerSignum) {
this.orderOwnerSignum = orderOwnerSignum;
}
public int getDuartion() {
return duartion;
}
public void setDuartion(int duartion) {
this.duartion = duartion;
}
public String getProcessInstanceUUID() {
return processInstanceUUID;
}
public void setProcessInstanceUUID(String processInstanceUUID) {
this.processInstanceUUID = processInstanceUUID;
}
#JsonSerialize(using=JsonDateSerializer.class)
public Date getOrderDate() {
return orderDate;
}
public void setOrderDate(Date orderDate) {
this.orderDate = orderDate;
}
#JsonSerialize(using=JsonDateSerializer.class)
public Date getOrderDeliveryDate() {
return orderDeliveryDate;
}
public void setOrderDeliveryDate(Date orderDeliveryDate) {
this.orderDeliveryDate = orderDeliveryDate;
}
#JsonSerialize(using=JsonDateSerializer.class)
public Date getModifiedDate() {
return modifiedDate;
}
public void setModifiedDate(Date modifiedDate) {
this.modifiedDate = modifiedDate;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getComments() {
return comments;
}
public void setComments(String comments) {
this.comments = comments;
}
#JsonSerialize(using=JsonProductSerializer.class)
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
}
//============================Product.java=========================
package my.pkg;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
#Entity
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long productID;
private String productName;
private String productCategory;
private String productDesc;
private Long productOwnerId;
private Long productHierarchyId;
private String productProcessID;
private Long productGroupID;
public Long getProductID() {
return productID;
}
public void setProductID(Long productID) {
this.productID = productID;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public String getProductCategory() {
return productCategory;
}
public void setProductCategory(String productCategory) {
this.productCategory = productCategory;
}
public String getProductDesc() {
return productDesc;
}
public void setProductDesc(String productDesc) {
this.productDesc = productDesc;
}
public Long getProductOwnerId() {
return productOwnerId;
}
public void setProductOwnerId(Long productOwnerId) {
this.productOwnerId = productOwnerId;
}
public Long getProductHierarchyId() {
return productHierarchyId;
}
public void setProductHierarchyId(Long productHierarchyId) {
this.productHierarchyId = productHierarchyId;
}
public String getProductProcessID() {
return productProcessID;
}
public void setProductProcessID(String productProcessID) {
this.productProcessID = productProcessID;
}
public Long getProductGroupID() {
return productGroupID;
}
public void setProductGroupID(Long productGroupID) {
this.productGroupID = productGroupID;
}
}
//=================JSONProductSerializer.java=========================
//the commented part in the below code didn't work either
//=====================================================================
package my.pkg;
import java.io.IOException;
import org.springframework.stereotype.Component;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
/**
* Used to serialize com.xxxx.persistence.entity.Product, which is not a common JSON
* type, so we have to create a custom serialize method;.
*
* source: google.com
*/
#Component
public class JsonProductSerializer extends JsonSerializer<Product>{
#Override
public void serialize(Product product, JsonGenerator gen, SerializerProvider provider)
throws IOException, JsonProcessingException {
synchronized(product) {
/*gen.writeStartObject();
gen.writeNumberField("productID", product.getProductID());
gen.writeStringField("productName", product.getProductName());
gen.writeStringField("productCategory", product.getProductCategory());
gen.writeStringField("productDesc", product.getProductDesc());
gen.writeNumberField("productOwnerId", product.getProductOwnerId());
gen.writeNumberField("productHierarchyId", product.getProductHierarchyId());
gen.writeStringField("productProcessID", product.getProductProcessID());
gen.writeNumberField("productGroupID", product.getProductGroupID());
gen.writeEndObject();*/
gen.writeNumber(product.getProductID());
gen.writeString(product.getProductName());
gen.writeString(product.getProductCategory());
gen.writeString(product.getProductDesc());
gen.writeNumber(product.getProductOwnerId());
gen.writeNumber(product.getProductHierarchyId());
gen.writeString(product.getProductProcessID());
gen.writeNumber(product.getProductGroupID());
}
}
}

Answer 1

Actually, the problem turned out to be with the java.util.Date serialization with com.fasterxml.jackson (latest version of jackson) package. I reverted to org.codehaus.jackson and everything works like a charm.