滚动条滚动异步加载数据（类似QQ空间）

package com.servlet; import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayList; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.StringUtils; import net.sf.json.JSONArray; import net.sf.json.JSONObject; public class ScrollServlet extends HttpServlet { /** * */ private static final long serialVersionUID = 1L; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); //GetDataToIndexFromServer(request, response); // GetDataFromServer(request, response); GetDataToImgsFromServer(request, response); // GetDataToWordFromServer(request, response); } public void GetDataToIndexFromServer(HttpServletRequest request,HttpServletResponse response) throws IOException{ PrintWriter out = response.getWriter(); String n = request.getParameter("begin"); int i = 0; if(null != n && n != ""){ i = Integer.parseInt(n); } StringBuffer buffer = new StringBuffer(); boolean emptyData = true; if(i > 15){//第五次滚动时 emptyData = false; }else{ for (int j = 0; j < 100; j++) { buffer.append("第"+i+"加载：圣诞节付款是发说<br>"); } emptyData = true; } out.print("{data:'"+buffer.toString()+"',isHaveContent:"+emptyData+"}"); out.flush(); out.close(); } public void GetDataFromServer(HttpServletRequest request,HttpServletResponse response) throws IOException{ String resp = ""; PrintWriter out = response.getWriter(); String n = request.getParameter("begin"); for(int i = 0; i <= 1000; i++) { resp += "<p><span>" + n + "</span> This content is dynamically appended " + "to the existing content on scrolling.</p>" ; } out.print("{data:'"+resp+"',flag:'success'}"); out.flush(); out.close(); } /*** * 图片加载 * @param request * @param response * @throws IOException */ public void GetDataToImgsFromServer(HttpServletRequest request,HttpServletResponse response) throws IOException{ PrintWriter out = response.getWriter(); List<List<ImgPo>> items = new ArrayList<List<ImgPo>>(); String count = request.getParameter("begin"); int count_ = 1; if(StringUtils.isNotEmpty(count)){ count_ = Integer.parseInt(count); } if(count_ <= 10){ for(int i = 5 ;i < 9 ; i++){ List<ImgPo> imgs = new ArrayList<ImgPo>(); imgs.add(new ImgPo("2015-04-21新闻和报纸摘要","images_test/img/"+i+".png")); imgs.add(new ImgPo("2015-04-21新闻和报纸摘要","images_test/img/"+(i+4)+".png")); items.add(imgs); } } JSONObject obj = new JSONObject(); obj.put("items", items); System.out.println("==============================================================="); System.out.println(obj.toString()); System.out.println("==============================================================="); out.print(obj.toString()); out.flush(); out.close(); } /*** * 文字加载显示 * @param request * @param response * @throws IOException */ public void GetDataToWordFromServer(HttpServletRequest request,HttpServletResponse response) throws IOException{ PrintWriter out = response.getWriter(); String count = request.getParameter("begin"); int count_ = 1; if(StringUtils.isNotEmpty(count)){ count_ = Integer.parseInt(count); } List<String> items = new ArrayList<String>(); // if(count_ <= 3){ for(int i = 1; i <20 ; i++){ items.add("第"+i+"次加载。。第"+count+"滚动加载"); } // } System.out.println("==========================="); JSONObject obj = new JSONObject(); obj.put("items", items); out.print(obj.toString()); out.flush(); out.close(); } }