Pass array data from javascript in browser to spring mvc controller using ajax

Question

I would like to pass an array from javascript in web browser to a Spring MVC controller using AJAX

In javascript, I have

var a = [];
a[0] = 1;
a[1] = 2;
a[2] = 3;

// how about multiple arrays as well?

$.ajax({
    type : "POST",
    url : "/myurl",
    data : //not sure how to write this, ("a="+a), ?
    success : function(response) {
       // do something ... 
    },
    error : function(e) {
       alert('Error: ' + e);
    }
}); 

In Java, I would like to create a class to receive data from AJAX, and I create a class to receive data

package com.amazon.infratool.ui;

import lombok.Getter;
import lombok.Setter;


@Setter @Getter
public class RepairInfomationParameters {
//how to write this variable?
    List<String> a = null; // is it something like this?
}

What is the correct way to do this? Thanks!

Answer 1

You can do this from the JavaScript side:

$.ajax({
    type : "POST",
    url : "/myurl",
    data : {
        myArray: a //notice that "myArray" matches the value for @RequestParam
                   //on the Java side
    },
    success : function(response) {
       // do something ... 
    },
    error : function(e) {
       alert('Error: ' + e);
    }
}); 

Then on the Java side (in Spring 3), assuming that this method is mapped by /myurl:

public String controllerMethod(@RequestParam(value="myArray[]") Integer[] myArray){
    ....
}

I believe the following will also work:

public String controllerMethod(@RequestParam(value="myArray[]") List<Integer> myArray){
    ....
}

Spring is smart enough to figure out how to do the binding.

For multiple arrays, you might want to just have a command object:

public class MyData {
    private List<Integer> firstArray;
    private List<Integer> secondArray;
    private List<Integer> thirdArray;

    ...
    ...
}

Then on the JavaScript side:

$.ajax({
    type : "POST",
    url : "/myurl",
    data : {            
        myData: {
           "firstArray": firstArray,
           "secondArray": secondArray,
           "thirdArray": thirdArray
        }            
    },
    success : function(response) {
       // do something ... 
    },
    error : function(e) {
       alert('Error: ' + e);
    }
}); 

On the Java side, you can bind using @ModelAttribute:

public String controllerMethod(@ModelAttribute(value="myData") MyData myData) throws ParseException {
    ....
}

EDIT

Changed the @RequestParam annotation to use myArray[] instead of just myArray, since this change appears to have been made in Spring after this answer was first posted.

Answer 2

It is very simple passing such data to the Spring MVC controller, when you have in mind that data is being parsed from string. So if you want to get an array/list in the controller - pass a stringified version of the array:

public String method(
        @RequestParam(value = "stringParam") String stringParam,
        @RequestParam(value = "arrayParam") List<String> arrayParam) {
    ...
}

and the corresponding javascript with jQuery would be like:

$.post("/urlToControllerMethod",
    {
        "stringParam" : "test",
        "arrayParam" : [1, 2, 3, "test"].toString()
    }
);

Note: the parameter type

List<String> arrayParam

could be as well replaced with the array equivalent

String[] arrayParam

Answer 3

Vivin Paliath doesn't work unless you use myArray[]

public String controllerMethod(@RequestParam(value="myArray[]") Integer[] myArray){
    ...
}

Answer 4

Fully tested solution

$.ajax({
    type : "POST",
    url : "/myurl",
    data : {
        myArray: a //notice that "myArray" matches the value for @RequestParam
                   //on the Java side
    },
    success : function(response) {
       // do something ... 
    },
    error : function(e) {
       alert('Error: ' + e);
    }
}); 

@RequestMapping(value = "/save/", method = RequestMethod.POST)
    public String controllerMethod(@RequestParam(value="myArray[]") List<Integer> myArray){
        System.out.println("My Array"+myArray.get(0));
        return "";
    }