passing JSON data to a Spring MVC controller

Question

I need to send a JSON string to Spring MVC controller.But I do not have any form bindings to it , I just need to send a plain JSON data to Controller class.I am making jQuery AJAX call to the Controller method like the below code.

$.ajax ({
    url: "./save",
    type: "POST",
    data: JSON.stringify(array),
    dataType: "json",
    contentType: "application/json; charset=utf-8",
    success: function(){
        alert("success ");
    }
});

But how do I retrieve it in the Controller method?(Note: It is just plain JSON data and not a form submission).

Answer 1

You can stringify the JSON Object with JSON.stringify(jsonObject) and receive it on controller as String.

In the Controller, you can use the javax.json to convert and manipulate this.

Download and add the .jar to the project libs and import the JsonObject.

To create an json object, you can use

JsonObjectBuilder job = Json.createObjectBuilder();
job.add("header1", foo1);
job.add("header2", foo2);
JsonObject json = job.build();

To read it from String, you can use

JsonReader jr = Json.createReader(new StringReader(jsonString));
JsonObject json = jsonReader.readObject();
jsonReader.close();

Answer 2

Add the following dependencies

<dependency>
    <groupId>org.codehaus.jackson</groupId> 
    <artifactId>jackson-mapper-asl</artifactId>
    <version>1.9.7</version>
</dependency>

<dependency>
    <groupId>org.codehaus.jackson</groupId> 
    <artifactId>jackson-core-asl</artifactId>
    <version>1.9.7</version>
</dependency>

Modify request as follows

$.ajax({ 
    url:urlName,    
    type:"POST", 
    contentType: "application/json; charset=utf-8",
    data: jsonString, //Stringified Json Object
    async: false,    //Cross-domain requests and dataType: "jsonp" requests do not support synchronous operation
    cache: false,    //This will force requested pages not to be cached by the browser          
    processData:false, //To avoid making query String instead of JSON
    success: function(resposeJsonObject){
        // Success Message Handler
    }
});

Controller side

@RequestMapping(value = urlPattern , method = RequestMethod.POST)
public @ResponseBody Person save(@RequestBody Person jsonString) {

   Person person=personService.savedata(jsonString);
   return person;
}

@RequestBody - Covert Json object to java
@ResponseBody- convert Java object to json

Answer 3

1. Html

   $('#save').click(function(event) {        
       var jenis = $('#jenis').val();
       var model = $('#model').val();
       var harga = $('#harga').val();
       var json = { "jenis" : jenis, "model" : model, "harga": harga};
       $.ajax({
           url: 'phone/save',
           data: JSON.stringify(json),
           type: "POST",           
           beforeSend: function(xhr) {
               xhr.setRequestHeader("Accept", "application/json");
               xhr.setRequestHeader("Content-Type", "application/json");
           },
           success: function(data){ 
               alert(data);
           }
       });
   
       event.preventDefault();
   });
   

   2. Controller

      @Controller
      @RequestMapping(value="/phone")
      public class phoneController {
      
          phoneDao pd=new phoneDao();
      
          @RequestMapping(value="/save",method=RequestMethod.POST)
          public @ResponseBody
          int save(@RequestBody Smartphones phone)
          {
              return pd.save(phone);
          }
      

   3. Dao

      public Integer save(Smartphones i) {
          int id = 0;
          Session session=HibernateUtil.getSessionFactory().openSession();
          Transaction trans=session.beginTransaction();
          try {
              session.save(i);   
              id=i.getId();
              trans.commit();
          }
          catch(HibernateException he){}
          return id;
      }