为啥值没传过来啊？

package com.imooc.learn;

public class Employee {

private String emno;

private String position;

private String department;

public Employee() {

}

public Employee(String emno, String position, String department) {

super();

this.emno = emno;

this.position = position;

this.department = department;

}

public String getEmno() {

return emno;

}

public void setEmno(String emno) {

this.emno = emno;

}

public String getPosition() {

return position;

}

public void setPosition(String position) {

this.position = position;

}

public String getDepartment() {

return department;

}

public void setDepartment(String department) {

this.department = department;

}

package com.imooc.learn;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

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 com.alibaba.fastjson.JSON;

/**

* Servlet implementation class Ajax

@WebServlet("/el")

public class Ajax extends HttpServlet {

private static final long serialVersionUID = 1L;

/**

* @see HttpServlet#HttpServlet()

public Ajax() {

super();

// TODO Auto-generated constructor stub

}

/**

* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

List<Employee> list=new ArrayList<Employee>();

list.add(new Employee("小红","职员","人事部 "));

list.add(new Employee("小明","职员","技术部 "));

list.add(new Employee("小白","经理","事业部 "));

String json=JSON.toJSONString(list);

response.setContentType("text/html;charset=utf-8");

}

<!DOCTYPE html>

<html>

<head>

<title>Insert title here</title>

</head>

<body>

var xmlHttp;

if(window.XMLHttpRequest){

xmlHttp=new XMLHttpRequest();

}else{

xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");

}

xmlHttp.open("GET","/js/el",true);

xmlHttp.send();

document.getElementById("one").onclick=function (){

xmlHttp.onreadystatechange=function(){

if(xmlHttp.readyState==4&&xmlHttp.status==200){

var text=xmlHttp.responseText;

console.log(text);

var jasn=JSON.parse(text);

var empl="";

for(var i=0;i<jasn.length;i++){

var emp=jasn[i];

empl=emp.emno;

empl=emp.position;

empl=emp.department;

}

document.getElementById("one").innerHTML=empl;

}

</script>

</body>

</html>

慕用4915122 2021-01-17

源自：jQuery与Ajax入门 2-8 自由编程

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2回答

好帮手慕小脸回答被采纳获得+3积分 2021-01-19 19:11:48

同学你好，很抱歉，上述贴出的截图未贴全，望谅解~

1、在Ajax类中，需添加response.getWriter().println()在servlet中输出html内容，使浏览器解析并显示出来。

2、在页面中，如下代码放置位置有误，应放置在最开始位置，修改如下：

修改后完整代码如下所示：

@WebServlet("/el1") public class Ajax extends HttpServlet {  private static final long serialVersionUID = 1L;  /** * * @see HttpServlet#HttpServlet() * */  public Ajax() {  super(); 

// TODO Auto-generated constructor stub<br><br> }<br><br>   /**<br>  * <br>  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse<br>    *      response)<br>    * <br>  */<br><br> protected void doGet(HttpServletRequest request, HttpServletResponse response)<br>          throws ServletException, IOException {<br><br>      List<Employee> list = new ArrayList<Employee>();<br><br>        list.add(new Employee("小红", "职员", "人事部 "));<br><br>     list.add(new Employee("小明", "职员", "技术部 "));<br><br>     list.add(new Employee("小白", "经理", "事业部 "));<br><br>     String json = JSON.toJSONString(list);<br><br>      response.setContentType("text/html;charset=utf-8");<br>     response.getWriter().println(json);<br> }<br><br>}<br>

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <input type="submit" value="员工列表" id="one"> <input type="submit" value="职位列表" id="two"> <input type="submit" value="部门列表" id="three"> <div id="div"></div> <script type="text/javascript"> document.getElementById("one").onclick = function() { var xmlHttp; if (window.XMLHttpRequest) { xmlHttp = new XMLHttpRequest(); } else { xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); } xmlHttp.open("GET", "/ajax/el", true); xmlHttp.send(); xmlHttp.onreadystatechange = function() { if (xmlHttp.readyState == 4 && xmlHttp.status == 200) { var text = xmlHttp.responseText; console.log(text); var jasn = JSON.parse(text); var empl = ""; for (var i = 0; i < jasn.length; i++) { var emp = jasn[i]; /* empl = emp.emno; empl = emp.position; empl = emp.department; */ empl = empl + emp.department + " "; } document.getElementById("div").innerHTML = empl; } } }; </script> </body> </html> 

祝学习愉快~

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