从JS Map和String创建JSON字符串 [英] Create json string from js Map and String

问题描述

我的REST控制器期望输入以下格式的请求，并将其成功转换为包含Map和String作为参数的Java对象:

My REST controller expects request input of the following format, which it successfully converts to a Java object containing a Map and a String as parameters:

{ 
"myMap" : { 
    "key1": "value1", 
    "key2": "value2", 
    "key3": "value3"},
"myString": "string value"
}

我正在从html表单获取数据，如下所示:

I am getting my data from an html form like so:

var myMap = new Map();
var String = document.getElementById('String').value;
for (var i = 0 ; i<anArray.length ; i++){
    var input = document.getElementsByClassName('input_' + (i+1));
    for (var j = 0 ; j<3 ; j++){
        if (input[j].checked){
            myMap.set(input[j].name, input[j].id);
        }
    }
}

基本上，这段代码可以归结为:

Basically, this code boils down to:

var myMap = new Map();
myMap.set("key1", "value1");
myMap.set("key2", "value2");
myMap.set("key3", "value3");

这将导致包含{key1 => value1，key2 => value2等}和一个String的映射.我一直试图像这样将其转换为json字符串，但是它似乎不起作用:

This results in a map containing {key1 => value1, key2 => value2, etc} and a String. I have been trying to turn this into a json string like so, but it doesn't seem to work:

var myJson = {};
myJson.myMap = myMap;
myJson.myString = myString;
var json = JSON.stringify(myJson);

但是，我最终得到以下字符串:`{"myMap":{}，"String":"myString"}''.因此，我可能需要做一些不同的事情来对地图进行字符串化，但是我尝试的任何方法都没有用.

However, I am ending up with the following string: `{"myMap":{},"String":"myString"}' . So I probably have to do something different to stringify a map, but nothing I try is working.

有人可以帮我吗?

推荐答案

您可以编写一个简短的转换函数，以使映射成为可以被字符串化的对象.

You can write a short conversion function to make a map into an object that can be stringified.

console.clear()

function mapToObj(map){
  const obj = {}
  for (let [k,v] of map)
    obj[k] = v
  return obj
}

const myMap = new Map();
myMap.set("key1", "value1");
myMap.set("key2", "value2");
myMap.set("key3", "value3");

const myString = "string value"

const myJson = {};
myJson.myMap = mapToObj(myMap);
myJson.myString = myString;
const json = JSON.stringify(myJson);

console.log(json)

这里是一个可以在Map存在但其他ES6构造不起作用的版本中运行的版本(尽管这似乎是编辑器设置问题).

Here is a version that that presumably would work where Map exists but some other ES6 constructs do not (though, this seems like an editor settings issue).

console.clear()

function mapToObj(map){
  var obj = {}
  map.forEach(function(v, k){
    obj[k] = v
  })
  return obj
}

var myMap = new Map();
myMap.set("key1", "value1");
myMap.set("key2", "value2");
myMap.set("key3", "value3");

var myString = "string value"

var myJson = {};
myJson.myMap = mapToObj(myMap);
myJson.myString = myString;
var json = JSON.stringify(myJson);

console.log(json)

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