How to pass array to background in ajax

This time I will show you how ajax transfers an array to the background. What are the precautions for ajax to transfer an array to the background? The following is a practical case, let's take a look.

Preface

We are using ajax to asynchronously submit the multi-select box to get the ID of the object that needs to be operated. At this time, we can put each Make an object with the id, then put it into an array, and then use

JSON.stringify() to format the array as json; in the background, parse our json characters in the inputStream String , then just use:

new JSONArray() Get the json array, loop to parse the attributes we want:

var countsCheckBox = $("input[type='checkbox']:checked"); 
 var booksid = []; 
 for(var i=0;i<countsCheckBox.length;i++){ 
 //使用[]取得元素是是一个domElement元素，取值需要使用.value， 
 //如果使用countsCheckBox.eq(i) 则是一个Obkject元素，就可以使用val()取值 
 //alert(countsCheckBox[i].value); 
 mysendbook_id = {}; 
 mysendbook_id[&#39;book_id&#39;] = countsCheckBox[i].value; 
 booksid[i] = mysendbook_id; 
 } 
 //alert(booksid); 
  var confirmdel= confirm(&#39;确认要删除吗?&#39;); 
  if(confirmdel){ 
  //开始请求删除 
   $.ajax({ 
     url:&#39;selectdelbooks&#39;, 
     data:JSON.stringify(booksid), 
     type:&#39;post&#39;, 
     success:function(res){ 
      alert("删除成功"); 
     location.replace("/TheDemo/books/pageBooksShow"); 
     } 
     }); 
  }

In the above js we put Put each selected id into the "book_id" attribute of mysendbook_id, and then put this object into the booksid array; use

JSON.stringify(bookid)# when sending an asynchronous request. ##Format this booksid array and get a json array.

Let’s look at how we receive it in the background:

One is to make a class with a list. This list contains a class with only one attribute for bookid, and then use The annotation

@RequestBody

is added to this formal parameter. But this is more troublesome; Another way is to get data from the input stream, use

IOUtils.toString

to convert the inputStream into a string, and then use new JSONArray(mybooksid); Get this json arrayTo get the attribute value of book_id in each json

<span style="font-family:SimSun;font-size: 10.5pt;"> </span><span style="font-family:KaiTi_GB2312;font-size:14px;"> @RequestMapping("selectdelbooks") 
 public String selectdelbooks(HttpServletRequest request) throws Exception { 
  ServletInputStream inputStream = request.getInputStream(); 
  String mybooksid = IOUtils.toString(inputStream); 
  JSONArray jsonarr = new JSONArray(mybooksid); 
  List<String> book_id =new ArrayList<String>(); 
  for (int i=0;i<jsonarr.length();i++){ 
   book_id.add(((JSONObject)jsonarr.get(i)).getString("book_id")); 
  }...</span>

In this way we get a list with the id value we selected.

Information in the database:

Multiple selection on the page:

The selection obtained in the background Book ID:

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Recommended reading:

How to implement AJAX paging effect

How to submit a form using Ajax and receive the json data

Ajax to implement infinite loading of lists and secondary drop-down menu options (with code)

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