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JSON defined syntax [json]

2022-07-21 18:34:00 【Java code evolution ing】

JSON The grammar of definition

grammar ( The basic rule ):

Data in name value pairs : JSON Data is made up of key value pairs
- Name value pair middle ( That is, between name and value ) Use :( The colon ) separate
- Keys can be enclosed in quotation marks , You can also use no quotes , And you can use single quotation marks or double quotation marks
- Values can be of the following types :
  1. Numbers ( Integer or floating point )
  2. character string (( Use double quotation marks )
  3. Boolean value (true / false)
  4. Array ( Square brackets ([]) in
    - eg:{“persons” : [ {} , {} ] }
      - The key at this time is persons, And the value is an array ( [] ), Multiple arrays can be nested JSON object
  5. JSON object ( In curly brackets ( {} ) in )
    - eg:{“address” : {“province” : “ shaanxi ”, … }}
      - The key at this time is address, And value is another JSON object
  6. null
    - We seldom use null As value
Data consists of commas (,) Separate
- That is, multiple key value pairs are separated by commas
Curly braces hold objects
- That is to use {}( Curly braces ) Definition JSON Format
Square brackets hold arrays
- That is to say [] ( square brackets ) Represents an array

For example, to understand : ( How to define JSON object )

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title> Definition JSON object </title>
		<script> //1.  Define the basic format  var person = {
      "name":" Zhang San ","age":23,"gender":true}; // Do a print and a test  alert(person); //2.  Nesting format : {} -> [] ,  This means JSON Object [] Array  var persons = {
       "persons" : [ {
      "name":" Zhang San ","age":23,"gender":true}, {
      "name":" Li Si ","age":23,"gender":true} ] } // Do a print and a test  alert(persons); //3.  Nesting format : [] -> {} ,  Here, it means that the array is nested JSON object  var ps = [ {
      "name":" Li Si ","age":23,"gender":true}, {
      "name":" Li Si ","age":23,"gender":true}, {
      "name":" Li Si ","age":23,"gender":true}, {
      "name":" Li Si ","age":23,"gender":true} ] // Do a print and a test  alert(ps); </script>
	</head>
	<body>
	</body>
</html>

Be careful : Here we are creating JSON object , It's just that this is JavaScript Code area , Let's create JSON The object will then be directly resolved to the corresponding JavaScript object