Analysis and application of Ajax technology in 13 springboot project

Jason 2020-11-10 12:44:31
analysis application ajax technology springboot


Ajax Technical introduction

Background analysis ?

Today, with the rapid development of Internet , Conventional WEB application , For high concurrency 、 High performance 、 The demand for high reliability is imminent . Single thread mode of client-side and server-side interaction mode has been unable to meet the needs of the current stage . We need to be asynchronous 、 Load on demand to get data from the server and refresh in time , To improve the user experience , therefore Ajax The birth of Technology .

Ajax What is it? ?

Ajax (Asynchronous JavaScript and XML) It's a kind of Web Application client technology , You can use client script (javascript) Asynchronous communication with server applications ( Multiple threads can interact with the server at the same time ), And after getting the server-side data on demand , Local refresh can be done , In order to improve the data response and rendering speed .

Ajax Application scenarios ?

Ajax The biggest advantage of technology is the underlying asynchronous , Then partial refresh , To improve the user experience , This technology is now well used in many projects , for example :

  • Commodity system .
  • Evaluation system .
  • Map system .
  • …..

AJAX You can just send and retrieve the necessary data to the server , And in the client side JavaScript Processing the response from the server . This reduces the amount of data exchanged between the server and the browser , The server responds faster . but Ajax Technology also has disadvantages , The biggest disadvantage is that cross domain access is not available directly .

Ajax Application model analysis ?

Ajax Quick start

Ajax Request response process analysis

The traditional way is web Request and response ( The client has to wait for the response ), As shown in the figure :

image.png

Ajax How to request and respond ( The key is that the client does not block ), As shown in the figure :

image.png

Ajax Programming steps and template code analysis

Ajax The basic steps of coding ?( The key is ajax The entrance of Technology -XMLHttpRequest-XHR object )

First step : be based on dom Event creation XHR object
The second step : stay XHR Register state listener on object ( Monitor the communication process between client and server )
The third step : Establish a connection with the server ( Specify request method , request url, Synchronous or asynchronous )
Step four : Send a request ( Pass the request data to the server )

Ajax The template code for the encoding process is as follows :

var xhr=new XMLHttpRequest();
xhr.onreadystatechange=function(){
if(xhr.readyState==4&&xhr.status==200){
console.log(xhr.responseText)
}
}
xhr.open("GET",url,true);
xhr.send(null);

SpringBoot project Ajax Introduction analysis of technology application

First step : Create project module, As shown in the figure :

image.png

The second step : add to Spring web rely on , The code is as follows :

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

The third step : establish AjaxController Handle client requests , The code is as follows :

package com.cy.pj.ajax.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class AjaxController {
@RequestMapping("/doAjaxGet01")
public String doAjaxGet01(){
return "Response Result Of Ajax Get Request 01 ";
}
}

Step four : In the project static Under the table of contents , Create a page ajax-01.html, The code is as follows :

html The element code is as follows :

<h1>The Ajax 01 Page</h1>
<fieldset>
<legend>Ajax asynchronous Get request </legend>
<button onclick="doAjaxGet01()">Ajax Get Request</button>
<span id="result">Data is Loading ...</span>
</fieldset>

javascript The script code is as follows :

function doAjaxGet01(){
//debugger// Client breakpoints ( This breakpoint takes effect by opening the console )
//1. establish XHR object (XmlHttpRequest)-Ajax The entry object of the application
let xhr=new XMLHttpRequest();
//2. stay XHR Register state listener on object ( Get the server response results and update to the page result Location )
xhr.onreadystatechange=function(){// Event handler ( The communication state between the client and the server changes This function is executed when )
//readyState==4 Indicates that the server responds that the client data has been received .
if(xhr.readyState==4){
if(xhr.status==200){//status==200 Indicates that the request processing is OK
document.getElementById("result").innerHTML=
xhr.responseText;
}
}
}
//3. Establish a connection with the server ( Specify request method , request url, asynchronous )
xhr.open("GET","http://localhost/doAjaxGet01",true);//true On behalf of the asynchronous
//4. Send a request to the server
xhr.send(null);//get request send Methods do not transfer data or write a null
console.log("===main thread===")
// If it is an asynchronous client, the execution is finished send Will continue down .
}

Step five : start-up Tomcat Service and access test analysis .

image.png

Click on Ajax Get Request Button , Detect page data updates .

Step six : During the start-up and access process Bug analysis

  • There is no response when you click the button

image.png

  • The object accessing the specified property does not exist

image.png

  • Cross domain access

image.png

Ajax Basic business implementation

Basic business description

The key code design and implementation of the server

Client key code design and implementation

Ajax Advanced technology implementation

Ajax Encapsulation of code

Ajax The implementation of small programming framework

Ajax Technology in Jquery Application in

Jquery brief introduction

Jquery Commonly used ajax Function analysis

Jquery in Ajax The basic application implementation of function

summary (Summary)

This chapter mainly introduces Ajax What is it? 、 Application scenarios 、 The communication model between client and server 、ajax The basic steps of programming 、 Packaging process and ajax Technology in some JS Applications in the framework, etc , And focus on the analysis in ajax Some debugging skills in the coding process .

版权声明
本文为[Jason]所创,转载请带上原文链接,感谢

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