jsp页面表单：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP 'ajax_form.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> <!-- 引入jquery --> <script type="text/javascript" src="${pageContext.request.contextPath }/js/jquery-1.9.1.js"></script> <script type="text/javascript"> $(function(){ //alert($('#p').html());弹出具体的内容：hello }); function lost(){ // alert($("#name").val()); //alert('失去焦点'); //alert($('#name')[0].value); 获取输入框的值，首先需要的到这个元素， //这个元素是jquery对象，需要转为dom对象，使用数组下标的方法.也可以使用 alert($("#name").val()); $.ajax({ url: "FromServlet", type:"post", data:"name="+$('#name')[0].value+"&password=123",//向后台传送的数据格式 dataType:"xml", success: function(data, textStatus){ //返回的是json的格式 //alert(data.password); //alert(data.name); //alert(textStatus); // $("#td").after("<font color='red' fontsize='5'>"+data.name+"用户名已经存在！</font>"); //返回的是xml数据格式 //需要将data这个dom对象中的数据解析出来 //首先需要将dom的对象转换成JQuery的对象 var jqueryObj = $(data); //children方法获取的是跟节点下的所有的孩子节点的文本节点（包括直接孩子和间接孩子节点） // var childs = jqueryObj.children(); //alert(childs.text()); //find方法查找是按照节点的名字来查询的.如果该节点下还有孩子节点，则取到的是孩子节点的文本节点，要和text()方法一起使用 var message = jqueryObj.find("name"); var message2 = jqueryObj.find("sex"); //获取节点的文本内容 var text = message.text(); var sex = message2.text(); alert(text); alert(sex); }, error:function(XMLHttpRequest, textStatus, errorThrown){ alert(textStatus); } }); } </script> </head> <body> <p id="p">hello</p> <form action=""> <table> <tr> <td>用户名：</td> <td id="td"><input type="text" name="name" onblur="lost()" id="name"/></td> <tr> <td>密 码</td> <td><input type="password" name="password"/></td> </tr> <tr> <td><input type="submit" value="提交"/></td> <td><input type="reset" value="重置"/></td> </tr> </table> </form> </body> </html>
后台的servlet代码：
package ajaxServlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import net.sf.json.JSONObject; public class FromServlet extends HttpServlet { /** * Constructor of the object. */ public FromServlet() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); } /** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //response.setContentType("text/html"); response.setCharacterEncoding("utf-8"); String name = request.getParameter("name"); String password = request.getParameter("password"); System.out.println("你输入的是="+name); System.out.println("你输入的密码是="+password); PrintWriter out = response.getWriter(); /**+++++++++++++++++++++json++++++++++++++++++++++++++++++++++++++*/ //String json = "{"success":"你好","type":"succ"}"; //out.println(json); //JSON对象 使用这种方法不用拼装json格式就可以自动转为json数据，不过要导入相应的jar文件，共六个 /*JSONObject jsonObject = new JSONObject(); jsonObject.accumulate("password", password).accumulate("name", name); response.setContentType("application/json"); response.getWriter().write(jsonObject.toString());*/ /**+++++++++++++++++++++xml++++++++++++++++++++++++++++++++++++++*/ out.println("<student>"); out.println("<name>"); out.println("<firstName>"); out.println("wkl"); out.println("</firstName>"); out.println("</name>"); out.println("<sex>"); out.println("M"); out.println("</sex>"); out.println("</student>"); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here } }