每次书写AJAX代码比较繁琐 步骤都是一样的,数据回显使用原生js代码也比较繁琐,可以使用jQuery对上述问题进行优化,jQuery不仅仅对dom操作进行了封装 同时也对AJAX提交和回显已经进行了封装,可大大简化AJAX的操作步骤
jQuery.ajax()的简单使用
基本语法为(经典语法):
前端代码
<html>
<head>
<title>$Title%sSourceCode%lt;/title>
<meta charset="UTF-8"/>
<script src="js/jquery.min.js"></script>
<script>
function checkUname(){
// 获取输入框中的内容
if(null == $("#unameI").val() || '' == $("#unameI").val()){
$("#unameInfo").text("用户名不能为空");
return;
}
$("#unameInfo").text("");
// 通过jQuery.ajax() 发送异步请求
$.ajax(
{
type:"GET",// 请求的方式 GET POST
url:"unameCheckServlet.do?", // 请求的后台服务的路径
data:"uname="+$("#unameI").val(),// 提交的参数
success:function(info){ // 响应成功执行的函数
$("#unameInfo").text(info)
}
}
)
}
</script>
</head>
<body>
<form action="myServlet1.do" >
用户名:<input id="unameI" type="text" name="uname" onblur="checkUname()">
<span id="unameInfo" style="color: red"></span><br/>
密码:<input type="password" name="pwd"><br/>
<input type="submit" value="提交按钮">
</form>
</body>
</html>
后台代码
package com.msb.servlet;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* @Author: Ma HaiYang
* @Description: MircoMessage:Mark_7001
*/
@WebServlet("/unameCheckServlet.do")
public class UnameCheckServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String uname = req.getParameter("uname");
String info="";
if("msb".equals(uname)){
info="用户名已经占用";
}else{
info="用户名可用";
}
// 向浏览器响应数据
resp.setCharacterEncoding("UTF-8");
resp.setContentType("text/html;charset=UTF-8");
resp.getWriter().print(info);
}
}JSON格式处理
前端代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="js/jquery.min.js"></script>
<script>
function testAjax(){
// 向后台发送一个ajax异步请求
// 接收响应的数据
$.ajax(
{
type:"GET",
url:"servlet1.do",
data:{"username":"zhangsan","password":"123456"},// key=value&key=value {"属性名":"属性值"}
dataType:"json",//以什么格式接收后端响应给我们的信息
success:function(list){
$.each(list,function(i,e){
console.log(e)
})
}
}
)
}
</script>
</head>
<body>
<input type="button" value="测试" onclick="testAjax()">
</body>
</html>后台代码
package com.msb.servlet;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.msb.pojo.Student;
import sun.util.calendar.LocalGregorianCalendar;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
/**
* @Author: Ma HaiYang
* @Description: MircoMessage:Mark_7001
*/
@WebServlet("/servlet1.do")
public class Servlet1 extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username = req.getParameter("username");
String password = req.getParameter("password");
System.out.println(username);
System.out.println(password);
Student stu1=new Student("小黑","男",10,new Date());
Student stu2=new Student("小白","男",10,new Date());
Student stu3=new Student("小黄","男",10,new Date());
Student stu4=new Student("小花","男",10,new Date());
ArrayList<Student> list =new ArrayList<>();
Collections.addAll(list,stu1,stu2,stu3,stu4);
GsonBuilder gb =new GsonBuilder();
gb.setDateFormat("yyyy-MM-dd");
Gson gson = gb.create();
String json = gson.toJson(list);
resp.setContentType("text/html;charset=UTF-8");
resp.setCharacterEncoding("UTF-8");
resp.getWriter().print(json);
}
}
标签：jQuery,resp,new,ajax,Student,简单,import,servlet,javax From： https://www.cnblogs.com/2324hh/p/17029183.html