将 javascript HashMap 发送到 Thymeleaf 字段构造函数

Question

I have a normal Java object that holds a parameter of type

private HashMap<String, String> lizt = new HashMap()

public ObjectTemp(HashMap<String, String> lizt ) {
    this.lizt = lizt ;
}

And a JavaScript map that contains the data

var map1 = new Map();

When the user clicks the button

<form  action="#" class="ui_formz" th:action="@{/SomeMethod}" th:object="${object_temp}"  method="post">

<button class="btn btn-primary" onclick="dothis(${object_temp.lizt })" type="button "> Buy </button>

</form>

In HTML, it calls a function

function dothis(argm){
    argm=map1;
}

However, it does not work. The constructor parameters do not receive or do anything. Anybody can explain why and what I am doing wrong?

For further explanation.

Basically, it does not register the map from JavaScript. It simply returns an object with an empty map

this.lizt = {[]}

I want to receive an HashMap stored in JavaScript to Java. Usually, the data would be an integer or a string or others primitive and it would do the job by simply storing the variable in HTML.

<input value="data_stored"></input>

This times it is an HashMap present in a JavaScript variable, not a string, so I don't know what to do. I am not working with a string but a map. Any solution?

Answer 1

Edit. Ok so i found the solution

kinda like this

Javascript to Java using JSON

the step are quite easy:

1. Javascript compiles bunch of data on current page and stores it in array.
2. Array object encoded into JSON.
3. Java code saves JSON.

to store data in array

map1.set(key1,value1);

to save data in json:

const objFromMap = Object.fromEntries(map1);
JSON.stringify(objFromMap);

to send data from JavaScript to Java

in javascript

function dothis(){

        var input1 = document.getElementById('str_res');
        input1.value = JSON.stringify(objFromMap);
        }

in hml thymleaf

<form  action="#" class="ui_formz" th:action="@{/ControllerMethod1}" th:object="${result_name}"  method="post">
                 <input type="hidden" id="str_res" value="random"  th:field="${comanda_temp.rsep}">
                    <button class="btn btn-primary" onclick="dothis()"
                         type="button ">Submit</button>
                 </form>

in Java Standard SprinBoot code:

Created new Object with only a String field called JsonHolder and his getter,setter and toString()

At the start added to the model with

        model.addAttribute("comanda_temp",new JsonHolder());

When clicked submit

@RequestMapping(value = "/ControllerMethod1",method = RequestMethod.POST)
public String SubmitJsonResult(Model model, @ModelAttribute("comanda_tempx") JsonHolder cmd) {
    PrintPrettyJson(cmd.getString());

PrintPrettyJson is just a private method to print to the console using gson library for Json parsing and manipulation

Also this solution should work with array or others type of list stored in a javascript data.