最后没有输出，别的都没问题，就最后一步

问题描述：

相关代码：

package com.imooc.ajax;

public class News {
	private String title;
	private String date;
	private String sourse;
	private String content;


	public News() {
		super();
	}
	public News(String title, String date, String sourse, String content) {
		super();
		this.title = title;
		this.date = date;
		this.sourse = sourse;
		this.content = content;
	}
	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
	public String getDate() {
		return date;
	}
	public void setDate(String date) {
		this.date = date;
	}
	public String getSourse() {
		return sourse;
	}
	public void setSourse(String sourse) {
		this.sourse = sourse;
	}
	public String getContent() {
		return content;
	}
	public void setContent(String content) {
		this.content = content;
	}

}

相关代码：

package com.imooc.ajax;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import com.alibaba.fastjson.JSON;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class NewsListServlet
 */
@WebServlet("/news_list")
public class NewsListServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public NewsListServlet() {
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		List list=new ArrayList();
		list.add(new News("TIOBE:2018年5月份全球编程语言排行榜","2018-5-1","TIOBE","..."));
		list.add(new News("TIOBE:2018年6月份全球编程语言排行榜","2018-6-1","TIOBE","..."));
		list.add(new News("TIOBE:2018年7月份全球编程语言排行榜","2018-7-1","TIOBE","..."));
		list.add(new News("TIOBE:2018年8月份全球编程语言排行榜","2018-8-1","TIOBE","..."));
		String json=JSON.toJSONString(list);
		System.out.println(json);
		response.setContentType("text/html;charset=UTF-8");
		response.getWriter().println(json);
	}

}

相关代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<div>
		<script>
			var xmlhttp;
			if(window.XMLHttpRequest){
				xmlhttp=new XMLHttpRequest();
			}else{
				xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
			}
			xmlhttp.open("GET","http://localhost:8080/ajax/news_list","true");
			xmlhttp.send();
			xmlhttp.onreadystatechange=function(){
				if(xmlhttp.readyState==4&&xmlhttp.status==200){
					var text=xmlhttp.responseText;
					alert(text);
					var json=JSON.parse(text);
					console.log(json);
					var html="";
					for(var i=0;i<json.length;i++){
						var news=json[i];
						//console.log(news);
						html=html+"<h1>"+news.title+"</h1>";
						html=html+"<h2>"+news.date+"&nbsp;"+news.sourse+"</h2>";
						html=html+"<hr/>"
					}

					document.getElementById("container").innerHTML=html;
				}
			}
		</script>
	</div>
</body>
</html>