Order of JSON objects using Jackson's ObjectMapper

Question

I'm using ObjectMapper to do my java-json mapping.

ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter(); ow.writeValue(new File( fileName +".json"), jsonObj); 

this is my java class:

public class Relation {  private String id; private String source; private String target; private String label; private List<RelAttribute> attributes;  public String getId() {     return id; }  public void setId(String id) {     this.id = id; }  public String getSource() {     return source; }  public void setSource(String source) {     this.source = source; }  public String getTarget() {     return target; }  public void setTarget(String target) {     this.target = target; }  public String getLabel() {     return label; } public void setLabel(String label) {     this.label = label; }  public void setAttributes(List<RelAttribute> attributes) {     this.attributes = attributes; }  public List<RelAttribute> getAttributes() {     return attributes; }  } 

this is what I get:

{     "id" : "-75da69d3-79c8-4000-a3d8-b10350a57a7e",     "attributes" : [ {       "attrName" : "ID",       "attrValue" : ""     }, {       "attrName" : "Description",       "attrValue" : "Primary Actor"     }, {       "attrName" : "Status",       "attrValue" : ""     } ],     "label" : "new Label",     "target" : "-46b238ac-b8b3-4230-b32c-be9707f8b691",     "source" : "-daa34638-061a-45e0-9f2e-35afd6c271e0"   } 

So my question now is, how can I get this json output:

{     "id" : "-75da69d3-79c8-4000-a3d8-b10350a57a7e",     "label" : "new Label",     "target" : "-46b238ac-b8b3-4230-b32c-be9707f8b691",     "source" : "-daa34638-061a-45e0-9f2e-35afd6c271e0",     "attributes" : [ {       "attrName" : "ID",       "attrValue" : ""     }, {       "attrName" : "Description",       "attrValue" : "Primary Actor"     }, {       "attrName" : "Status",       "attrValue" : ""     } ]    } 

I want it with same order as in my java declaration. Is there a way to specify it ? Maybe with annotations or stuff like that ?

Answer 1

@JsonPropertyOrder({ "id", "label", "target", "source", "attributes" }) public class Relation { ... } 

Answer 2

Do you know there is a convenient way to specify alphabetic ordering?

@JsonPropertyOrder(alphabetic = true) public class Relation { ... } 

If you have specific requirements, here how you configure custom ordering:

@JsonPropertyOrder({ "id", "label", "target", "source", "attributes" }) public class Relation { ... }