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Discussion on Jquery's Ajax asynchronous issues

零到壹度Original: 2018-03-29 09:55:241169browse

This article mainly shares with you a discussion on Jquery's Ajax asynchronous issues. It has a good reference value and I hope it will be helpful to everyone. Let’s follow the editor to have a look.

1. $.get(url, [data], [callback], [type]); can only be Asynchronous

2. $.post(url, [data], [callback], [type]); Can only be Asynchronous

#Parameter list:

# url: Represents the server-side address of the request;

## type: Indicates the data type returned by the server (jquery will automatically type conversion according to the specified type),

Commonly used return types: text, json, html, etc.

$.ajax({ option1:value1,option2:value2... } )

Commonly used options are as follows:

async: whether to be asynchronous, the default is true, which means asynchronous;

data: parameters sent to the server, it is recommended to use json Format;

dataType: the data type returned by the server, commonly used text and json;

success: successfully responds to the executed function, the corresponding type is the function type;

type : Request method, POST/GET;

URL: Request server-side address.

Let’s do an example demonstration:

AjaxServle.java

package ajax;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class AjaxServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//响应请求
		//返回参数会json类型的字符串，前端jquery会自动将字符串解析为json对象
		response.getWriter().write("{\"name\":\"Tom\",\"age\":18}");
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

TestAjax.html

<!DOCTYPE html>
<html>
  <head>
    <title>Jquery的Ajax异同步</title>
    <meta name="content-type" content="text/html; charset=UTF-8">
    <script type="text/javascript" src="jquery-1.11.3.min.js"></script>
    <script>
    
    	//Get异步响应
    	function fn1(){
	    	$.get(
	    		"/WEB/ajaxServlet", //访问的资源地址
	    		{"name":"zhangsan","age":22}, //请求服务器端的参数,可以是json格式 
	    		function(responseData) { //响应成功后执行的函数
					var str="name: "+responseData.name+"; age: "+responseData.age;
	    			document.getElementById("input1").value=str;
	    		}, 
	    		"json" //返回数据的格式
	    		)
    	}
    	
    	//Post异步响应
    	function fn2(){
    		$.post(
	    		"/WEB/ajaxServlet", //访问的资源地址
	    		{"name":"zhangsan","age":22}, //请求服务器端的参数,可以是json格式 
	    		function(responseData) { //响应成功后执行的函数
					var str="name: "+responseData.name+"; age: "+responseData.age;
	    			document.getElementById("input2").value=str;
	    		}, 
	    		"json" //返回数据的格式
	    		)
    	}
    	
    	//Ajax异步响应
    	function fn3(){
    		$.ajax(
    			{
    				url:"/WEB/ajaxServlet", 
    				async:true, // 异步
    				type:"POST", // 请求方式
					data:{"name":"lucy","age":18}, // 请求参数
					success:function(data){ // 请求成功执行函数
						document.getElementById("input3").value="Rose";
					},
					error:function(){
						alert("请求失败"); // 请求失败执行函数
					},
					dataType:"json"
    			}
    		)
    	}
    </script>
  </head>
  
  <body>
	<input type="button" value="Get异步响应" onclick="fn1()"><input type="text" id="input1">
	<br><br>
	<input type="button" value="Post异步响应" onclick="fn2()"><input type="text" id="input2">
	<br><br>
	<input type="button" value="Ajax异步响应" onclick="fn3()"><input type="text" id="input3">
  </body>
</html>

Instance effect 1: When the request is successful

Instance effect 2: Modify fn3 The url of () is "/WEB/ajaxServlet33", so that when the request fails

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