How to use jQuery to post JSON data to a Struts2 Action class

Question

I've a problem sending data from jQuery to struts2 action class. I have seen the question: JSON Jquery to Struts2 action but I don't understand the solution quite well.

Here is my problem:

The json array is like this:

[{"id":"1","code":"111","name":"ddd"},
 {"id":"2","code":"222","name":"sss"},
 {"id":"3","code":"333","name":"eee"}]

I want to send the json data to the struts2 action class. The jQuery code is like this:

var data = JSON.stringify(dataObj);
$.ajax({
  url: "Update",
  type: "post",
  data:  data,
  dataType: 'json',
  contentType:"application/json;charset=utf-8",
  success : function(){
    alert("You made it!");
  }
});

However, in Chrome's Development Tool, I have seen the data submitted to the server side. But on the server side, I don't know how receive the json data.

Action:

public class Update extends ActionSupport{
    private String data;

    public String getData(){
        return data;
    }

    public void setData(String data){
        this.data= data;
    }

    public String execute(){
        System.out.println(data);
        return SUCCESS;
    }
}

In this way, data is null.

I've also tried to use a List to receive JSON data. Changing "data" type from String to List<Node>, it failed again. Probably because I don't quite understand the OGNL model which Struts2 is using.

Please Help Me. Thank you very much!

Answer 1

{"id":"1","code":"111","name":"ddd"}

Step 1 : Create a bean/pojo to accumulate/encapsulate the above fields

class MyBean{
    String id,code,name;
    //getters & setters
}

Step 2 : Change your action code to receive a List of MyBeans

public class Update extends ActionSupport{
    private List<MyBean> data;

   //other code, getters & setters
}

Step 3: Configure your action to de-serialize JSON data and fill the action fields (using json-plugin)

    <action name="Update" class="Update">
        <interceptor-ref name="defaultStack"/>
         <interceptor-ref name="json">
            <param name="enableSMD">true</param>
        </interceptor-ref>
</action>

Step 4 : Make necessary changes in the ajax request body being sent to match the action-params/fields

var data = JSON.stringify(dataObj);
$.ajax({
  url: "Update",
  type: "post",
  data:  "data:"+data,
  dataType: 'json',
  contentType:"application/json;charset=utf-8",
  success : function(){
    alert("You made it!");
  }
});

The above code is untested.

Answer 2

Hey The problem is you are directly posting array of objects. So Struts2 don't know whicch method to call. Change your json data like below. Then it will work.

{"data":[{"id":"1","code":"111","name":"ddd"},
"id":"2","code":"222","name":"sss"},
{"id":"3","code":"333","name":"eee"}]}

Then inside the setter read with object

public void setData(List < Report > data) {
    System.out.println("Setter Call Flow");
    this.data = data;
}

Where Report is a java class contains id,code,name as it's members with setters and getters.