Details of the JavaScript process for parsing JSON data
- 2020-08-22 21:43:43
- OfStack
JSON (JavaScript Object Notation) a simple data format that is lighter than xml. JSON is the JavaScript native format, which means that no special API or toolkits are required to process JSON data in JavaScript.
The rule of JSON is simple: an object is an unordered collection of 'name/value' pairs. 1 object begins with "{" (left parenthesis) and ends with"} "(right parenthesis). Each "name" is followed by a ":" (colon); Use ", "(comma) between" name/value "pairs. Details refer to http: / / www json. org/json - zh. html
Here's a simple example:
js code
function showJSON() {
var user =
{
"username":"andy",
"age":20,
"info": { "tel": "123456", "cellphone": "98765"},
"address":
[
{"city":"beijing","postcode":"222333"},
{"city":"newyork","postcode":"555666"}
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
}
This represents an user object with attributes such as username, age, info, address, etc.
You can also use JSON to simply modify the data, as shown in the above example
js code
function showJSON() {
var user =
{
"username":"andy",
"age":20,
"info": { "tel": "123456", "cellphone": "98765"},
"address":
[
{"city":"beijing","postcode":"222333"},
{"city":"newyork","postcode":"555666"}
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
user.username = "Tom";
alert(user.username);
}
JSON provides json js package, download http: / / www json. org/json js, after introducing its then you can simply use object. toJSONString () converts JSON data.
js code
function showCar() {
var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow");
alert(carr.toJSONString());
}
function Car(make, model, year, color) {
this.make = make;
this.model = model;
this.year = year;
this.color = color;
}
You can use eval to convert JSON characters to Object
js code
function myEval() {
var str = '{ "name": "Violet", "occupation": "character" }';
var obj = eval('(' + str + ')');
alert(obj.toJSONString());
}
Or use the parseJSON() method
js code
function myEval() {
var str = '{ "name": "Violet", "occupation": "character" }';
var obj = str.parseJSON();
alert(obj.toJSONString());
}
Write an ajax example of JSON using prototype.
Write a servlet (I was servlet ajax. JSONTest1. java) write 1 sentence
java code
response.getWriter().print("{ \"name\": \"Violet\", \"occupation\": \"character\" }");
Write another request for ajax on the page
js code
function sendRequest() {
var url = "/MyWebApp/JSONTest1";
var mailAjax = new Ajax.Request(
url,
{
method: 'get',
onComplete: jsonResponse
}
);
}
function jsonResponse(originalRequest) {
alert(originalRequest.responseText);
var myobj = originalRequest.responseText.parseJSON();
alert(myobj.name);
}
prototype-1.5.1.js provides JSON method, ES104en. evalJSON(), you can modify the above method without using ES106en. js
js code
function jsonResponse(originalRequest) {
alert(originalRequest.responseText);
var myobj = originalRequest.responseText.evalJSON(true);
alert(myobj.name);
}
JSON also provides java http jar package: / / www json. org/java/index html API is also very simple, for example below
Add the request parameter in javascript
js code
function sendRequest() {
var carr = new Car("Dodge", "Coronet R/T", 1968, "yellow");
var pars = "car=" + carr.toJSONString();
var url = "/MyWebApp/JSONTest1";
var mailAjax = new Ajax.Request(
url,
{
method: 'get',
parameters: pars,
onComplete: jsonResponse
}
);
}
Using the JSON request string, you can simply generate JSONObject and parse it, modify servlet to add JSON processing (to use ES140en.jar)
java code
private void doService(HttpServletRequest request, HttpServletResponse response) throws IOException {
String s3 = request.getParameter("car");
try {
JSONObject jsonObj = new JSONObject(s3);
System.out.println(jsonObj.getString("model"));
System.out.println(jsonObj.getInt("year"));
} catch (JSONException e) {
e.printStackTrace();
}
response.getWriter().print("{ \"name\": \"Violet\", \"occupation\": \"character\" }");
}
You can also use JSONObject to generate JSON strings and modify servlet
java code
function showJSON() {
var user =
{
"username":"andy",
"age":20,
"info": { "tel": "123456", "cellphone": "98765"},
"address":
[
{"city":"beijing","postcode":"222333"},
{"city":"newyork","postcode":"555666"}
]
}
alert(user.username);
alert(user.age);
alert(user.info.cellphone);
alert(user.address[0].city);
alert(user.address[0].postcode);
user.username = "Tom";
alert(user.username);
}
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The above content is to introduce JavaScrip processing t analysis JSON data process details, hope to help you.