JSP实现留言板分页显示，新留言显示在第一个~

Posted 2020-09-20 赤红之瞳

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页面效果图：

留言Servlet-----MessageServlet

package cn.MuJH.newsManager.servlet;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
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 cn.MuJH.newsManager.biz.MessageManager;
import cn.MuJH.newsManager.biz.impl.MessageManagerImpl;
import cn.MuJH.newsManager.entity.Message;
import cn.MuJH.newsManager.entity.PageMsg;

@WebServlet(name = "msg", urlPatterns = { "/msg" })
public class MessageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
    public MessageServlet() {
        super();

    }

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

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  MessageManager mm=new MessageManagerImpl();
  String opr = request.getParameter("mth");
  String author =request.getParameter("author");
  String message =request.getParameter("message");
  if(opr!=null){
   　　if(author!=null || author!=""){
   　　SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
   　　Message msg=new Message(0,author,message,sdf.format(new Date()));
   　　mm.addMsg(msg);
   　　}
  }else{
   　　request.setAttribute("author", author);
   　　request.setAttribute("message", message);
  }

  PageMsg page=new PageMsg();
  page.setPageSize(5);   //每页显示留言条数
  int totalPage=mm.getTotalCount()%page.getPageSize()==0?mm.getTotalCount()/page.getPageSize():mm.getTotalCount()/page.getPageSize()+1;
  page.setTotalPage(totalPage);
  if(request.getParameter("pageIndex")==null||request.getParameter("pageIndex")==""){
  　　 page.setPageIndex(1);
  }else{
   　　page.setPageIndex(Integer.parseInt(request.getParameter("pageIndex")));
  }
  List<Message> list=mm.getMessageByPageindex(page.getPageIndex(), page.getPageSize());
  page.setList(list);
  request.setAttribute("page", page);

  request.getRequestDispatcher("message.jsp").forward(request, response);
}

}

见图：

页面内容---message.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery1.8.0.min.js"></script>
</head>
<body>
<h1>留言板</h1>
<c:forEach items="${page.list }" var="msg">
  <p>作者：${msg.author }</p>
  <p>内容：${msg.message }</p>
  <p>发表时间：${msg.pubdate }</p>
</c:forEach>
<input type="button" value="上一页" onclick="fenye(${page.pageIndex-1})"
<c:if test="${page.pageIndex eq 1 }">disabled="disabled"</c:if>
>

<input type="button" value="下一页" onclick="fenye(${page.pageIndex+1})"
<c:if test="${page.pageIndex eq page.totalPage }">disabled="disabled"</c:if>
>

<hr/>

<form action="msg?mth=save" method="post" id="myform" onsubmit="return check()">
  <p>用户名：<input type="text" name="author" id="author" value="${author }"/></p>
  <p>留言：<input type="text" name="message" id="message" value="${message }"/></p>
  <p><input type="submit" value="发表留言"/></p>
  <input type="hidden" name="pageIndex" id="pageIndex">
</form>

<script>
  function check(){
   if((document).getElementById("author").value==""){
    alert("用户名不能为空");
    document.getElementById("author").focus();
    return false;
   }
   if((document).getElementById("message").value==""){
    alert("用户名不能为空");
    document.getElementById("message").focus();
    return false;
   }
   return true;
  }
  function fenye(pageIndex){
   document.getElementById("pageIndex").value=pageIndex;
   document.getElementById("myform").action="msg";
   document.getElementById("myform").submit();
  }
</script>
</body>
</html>