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Today, I will talk to you about how to transmit Json data in Ajax. Many people may not know much about it. In order to make you understand better, the editor has summarized the following content for you. I hope you can get something according to this article.

6.JSON

JSON (JavaScript Object Notation) is a lightweight data exchange format. When using Ajax, we often use JSON to pass data. In this section, you will focus on JSON objects, JSON arrays, and how to pass JSON data in Ajax.

Introduction to 6.1JSON

(1) define JSON objects and JSON arrays

① JSON object

a. Define JSON object

Syntax:

In JavaScript, the JSON object is enclosed in curly braces and contains multiple sets of properties. Each attribute name and attribute value are separated by colons, multiple attributes are separated by commas, and the attribute name must be a string, as follows:

b. Working with JSON objects

You can get the corresponding value through "JSON object name .key", as follows:

Json.jsp

The running result is shown in the figure.

Figure running result

② JSON array

a. Define the JSON array

Syntax:

In JavaScript, the JSON array is enclosed in middle brackets and contains multiple JSON objects separated by commas, as follows:

b. Using the JSON array

You can obtain the corresponding value by "JSON object name [index] .key", as follows:

The running result is shown in the figure.

Figure running result

6.2 AJAX uses JSON to pass data

When using jQuery to implement AJAX, the client can use $.getJSON () to send data in JSON format to the server, and the server can also return data in JSON format to the client.

Syntax:

Example:

Client: json.jsp

Server side: MobileJSONServlet.java

The client uses $.getJSON to send JSON data {mobileNum: $mobile} to the server-side MobileJSONServlet. The server receives the value of mobileNum and returns it to the client in the format of a JSON object, such as {"msg": "bind successfully!" } . Finally, the client parses the JSON value returned by the server, such as result.msg.

In the above server-side code MobileJSONServlet, the JSON result is returned to the client in the form of string concatenation, such as {"msg": "bind successfully!" } . In addition, we can also use the JSONObject class on the server side to generate the JSON object and return it to the client, as follows:

Client: json.jsp

Server side: before using JSONObject, you need to import the following JAR file into the project, as shown in the table:

JSONObjectServlet.java

The client sends a request to the server-side JSONObjectServlet through $.getJSON () and passes the data {name:stuName,age:stuAge} in JSON format. The server encapsulates the data of the client into the Student object, then adds the Student object to the JSONObject object, and returns the JSONObject object to the client. Finally, the client receives the JSONObject object through the callback function parameter result, and escapes the stu in the JSONObject object into JSON string format through eval (result.stu), and then uses student.name to get the needed value.

After reading the above, do you have any further understanding of how to transfer Json data in Ajax? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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