Java Web 网络留言板6 MVC模式

两种转向的区别：

　　forward()

  request.setAttribute("message", message);
  request.getRequestDispatcher("/addResult.jsp").forward(request, response);

　　sendRedirect()

  response.sendRedirect("/guestbook6/getMessages.jsp");

 

区别：

1、forward可以读取转向前request对象通过setAttribute()方法所设定的属性值，sendRedirect()不能；

2、转向后，forward()方法显示的是原来Servlet的地址，即地址不变，而sendRedirect(“*****”)方法要变成*****地址；

3、forward()方法转向的速度要快，较sendRedirect()方法；

4、sendRedirect()方法可以转向到web应用之外的页面或者网站，

　　如：response.sendRedirect(" http://www.cnblogs.com/hongten/ ");

　　而forward()是不可以的； 

addMessage.jsp

代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@ include file="/header.jsp"%>
<style>
* { font-family: "宋体"; font-size: 14px }
</style>
<script type="text/javascript" src="<%=context%>/js/validation-framework.js"></script>
<script type="text/javascript" src="<%=context%>/fckeditor/fckeditor.js"></script>
<p align="center">
 请您输入留言
</p>
<p align="center">
 <a href="<%=context%>/servlet/getMessages">查看留言</a>
</p>
<form id="form1" name="form1" method="post"
 action="<%=context%>/servlet/addMessage"
 onsubmit="return doValidate(this)">
 <table width="650" height="400" border="0" align="center">
  <tr>
   <td width="150">姓名：</td>
   <td width="500">
    <input name="name" type="text" id="name" size="40" maxlength="20" />
   </td>
  </tr>
  <tr>
   <td>E-Mail：</td>
   <td>
    <input name="email" type="text" id="email" size="40" maxlength="40" />
   </td>
  </tr>
  <tr>
   <td>电话：</td>
   <td>
    <input name="phone" type="text" id="phone" size="40" maxlength="20" />
   </td>
  </tr>
  <tr>
   <td>主题：</td>
   <td>
    <input name="title" type="text" id="title" size="80" maxlength="80" />
   </td>
  </tr>
  <tr>
   <td valign="top">内容：</td>
   <td>
    <script type="text/javascript">
    var oFCKeditor = new FCKeditor("content");
    oFCKeditor.BasePath = '<%=context%>/fckeditor/' ;
    oFCKeditor.Height = 300 ;
    oFCKeditor.ToolbarSet = 'Basic';
    oFCKeditor.Create() ;
    </script>
   </td>
  </tr>
  <tr>
   <td></td>
   <td>
    <input type="submit" name="Submit" value="提交" />
    <input type="reset" name="Reset" value="重置" />
   </td>
  </tr>
 </table>
</form>
<%@ include file="/footer.htm"%>

OracleUtil.java

代码：

package webbook.util;

import java.sql.SQLException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;

public class OracleUtil {
 private String dataSourceName;
 private DataSource ds;

 public OracleUtil(String dataSourceName) {
  this.dataSourceName = dataSourceName;  
 }

 public OracleUtil() {  
 }

 public void setDataSourceName(String dataSourceName) {
  this.dataSourceName = dataSourceName;
 }

 public void init() {
  Context initContext;
  try {
   initContext = new InitialContext();
   ds = (DataSource) initContext.lookup(dataSourceName);
  } catch (NamingException e) {
   e.printStackTrace();
  }
 }

 public int update(String sql, String[] param) {
  int result = 0;
  QueryRunner qr = new QueryRunner(ds);
  try {
   result = qr.update(sql, param);
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return result;
 }

 public Object query(String sql, String[] param, ResultSetHandler rsh) {
  QueryRunner qr = new QueryRunner(ds);
  Object result = null;
  try {
   result = qr.query(sql, param, rsh);
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return result;
 }
}

AddMessageServlet.java

代码：

package webbook.guestbook;

import java.io.IOException;
import java.text.SimpleDateFormat;
import javax.servlet.ServletException;
import javax.servlet.http.*;
import webbook.util.*;

public class AddMessageServlet extends HttpServlet {
 private static final long serialVersionUID = -8349454122547148005L;

 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  String sql = "insert into guestbook (id,name,email,phone,title,content,time) values(gb_seq.nextval,?,?,?,?,?,?)";
  int result = 0;
  String message = "";
  request.setCharacterEncoding("utf-8");
  String name = request.getParameter("name");
  String title = request.getParameter("title");

  if (StringUtil.validateNull(name)) {
   message = "对不起，姓名不能为空，请您重新输入！<br>";
  } else if (StringUtil.validateNull(title)) {
   message = "对不起，主题不能为空，请您重新输入！<br>";
  } else {
   SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
   String param[] = { StringUtil.filterHtml(name), StringUtil.filterHtml(request.getParameter("email")),
     StringUtil.filterHtml(request.getParameter("phone")), StringUtil.filterHtml(title),
     request.getParameter("content"), sdf.format(new java.util.Date()) };
   OracleUtil db = new OracleUtil("java:/comp/env/jdbc/oracleds");
   db.init();
   result = db.update(sql, param);
   if (result == 0) {
    message = "对不起，添加留言不成功，请您重新输入！<BR>";
   } else {
    message = "祝贺您，成功添加留言。<BR>";
   }
  }
  request.setAttribute("message", message);
  request.getRequestDispatcher("/addResult.jsp").forward(request, response);
 }
}

addResult.jsp

代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@ include file="/header.jsp" %>
<style>
* { font-family: "宋体";font-size: 14px}
</style>
<%=request.getAttribute("message")%>
<a href="<%=context %>/addMessage.jsp">添加新的留言</a><BR>
<a href="<%=context %>/servlet/getMessages">查看所有留言内容</a><BR>
<%@ include file="/footer.htm"%>

getMessages.jsp

代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@page import="webbook.guestbook.Guestbook"%>
<%@ include file="/header.jsp"%>
<style>
* {font-family: "宋体";font-size: 14px}
</style>
<center>
 <a href="<%=context%>/addMessage.jsp">添加新的留言内容</a><br>
 留言内容<br><br>
 <%
  List list = (List)session.getAttribute("results"); 
  if(list!=null){
  for (int i = 0; i < list.size(); i++) {
   Guestbook gb = (Guestbook) list.get(i);
 %>
 <table width="600" border="1" bordercolor="000000"
  style="table-layout: fixed; word-break: break-all">
  <tr>
   <td width="100" bordercolor="ffffff">
    编号:
   </td>
   <td width="500" bordercolor="ffffff"><%=gb.getId()%></td>
  </tr>
  <tr>
   <td bordercolor="ffffff">
    姓名:
   </td>
   <td bordercolor="ffffff"><%=gb.getName()%></td>
  </tr>
  <tr>
   <td bordercolor="ffffff">
    电话:
   </td>
   <td bordercolor="ffffff"><%=StringUtil.chanageNull(gb.getPhone(), "没填")%></td>
  </tr>
  <tr>
   <td bordercolor="ffffff">
    email:
   </td>
   <td bordercolor="ffffff"><%=StringUtil.chanageNull(gb.getEmail(), "没填")%></td>
  </tr>
  <tr>
   <td bordercolor="ffffff">
    主题:
   </td>
   <td bordercolor="ffffff"><%=gb.getTitle()%></td>
  </tr>
  <tr>
   <td valign="top" bordercolor="ffffff">
    内容:
   </td>
   <td valign="top" bordercolor="ffffff"><%=StringUtil.chanageNull(gb.getContent(), "没填")%></td>
  </tr>
  <tr>
   <td bordercolor="ffffff">
    时间:
   </td>
   <td bordercolor="ffffff"><%=gb.getTime()%></td>
  </tr>
 </table>
 <br>
 <%}}%>
</center>
<%@ include file="/footer.htm"%>

GetMessagesServlet.java

代码：

package webbook.guestbook;

import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.*;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import webbook.util.OracleUtil;

public class GetMessagesServlet extends HttpServlet {
 private static final long serialVersionUID = 5964428201228635704L;

 public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  String sql = "select * from guestbook order by id desc";
  List list = null;
  OracleUtil db = new OracleUtil("java:/comp/env/jdbc/oracleds");
  db.init();
  list = (List) db.query(sql, null, new BeanListHandler(Guestbook.class));
  HttpSession session = request.getSession();
  session.setAttribute("results", list);
  response.sendRedirect("/guestbook6/getMessages.jsp");
 }
}

Guestbook.java

代码：

package webbook.guestbook;

public class Guestbook {
 private String content;
 private String email;
 private Integer id;
 private String name;
 private String phone;
 private String time;
 private String title;

 public String getContent() {
  return content;
 }

 public void setContent(String content) {
  this.content = content;
 }

 public String getEmail() {
  return email;
 }

 public void setEmail(String email) {
  this.email = email;
 }

 public Integer getId() {
  return id;
 }

 public void setId(Integer id) {
  this.id = id;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }

 public String getPhone() {
  return phone;
 }

 public void setPhone(String phone) {
  this.phone = phone;
 }

 public String getTime() {
  return time;
 }

 public void setTime(String time) {
  this.time = time;
 }

 public String getTitle() {
  return title;
 }

 public void setTitle(String title) {
  this.title = title;
 }
}