MVC設計模式-學習筆記
阿新 • • 發佈：2018-04-18
MVC設計模式-學習筆記1)如果嚴格按照MVC思想的話，瀏覽器首頁訪問的是控制器，然後再由控制器轉發到視圖
2)位於WEB-INF/目錄下的資源，客戶端無法直接訪問，只能通過服務端轉發進入
3)request對象也可用於資源的轉發
request
.getRequestDispatcher("/WEB-INF/success.html")
.forward(request,response);
4)通過正則表達式驗證中文：[\u4E00-\uFA29]+
5)對於重定向而言，前後的二個Request域對象不同，如果取值不到，返回"null"，不會報錯
2)位於WEB-INF/目錄下的資源，客戶端無法直接訪問，只能通過服務端轉發進入
3)request對象也可用於資源的轉發
request
.getRequestDispatcher("/WEB-INF/success.html")
.forward(request,response);
4)通過正則表達式驗證中文：[\u4E00-\uFA29]+
5)對於重定向而言，前後的二個Request域對象不同，如果取值不到，返回"null"，不會報錯
java代碼：
ModelBean
public class ModelBean { public boolean validate(String username){ boolean flag = false; //username.matches("[a-zA-Z0-9]+")) 用戶名是數字與字母 if(username!=null && username.matches("[\u4E00-\uFA29]+")){ flag = true; } return flag; } }
Demo8
import java.io.IOException; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import cn.itcast.web.domain.ModelBean; public class Demo8 extends HttpServlet { //NO1 public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { //轉發到view.html頁面 RequestDispatcher rd = request.getRequestDispatcher("/WEB-INF/view.html"); rd.forward(request,response); } //NO2 public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); String username = request.getParameter("username"); ModelBean mb = new ModelBean(); boolean flag = mb.validate(username); if(flag){ //將用戶名綁定到Request域對象中 request.setAttribute("USERNAME",username); /*轉發到ListServlet.java request .getRequestDispatcher("/ListServlet") .forward(request,response); */ //重定向到ListServlet.java response.sendRedirect("/day07/ListServlet"); }else{ request .getRequestDispatcher("/WEB-INF/fail.html") .forward(request,response); } } }
ListServlet
import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ListServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { String username = (String) request.getAttribute("USERNAME"); response.setContentType("text/html;charset=UTF-8"); response.getWriter().write("歡迎"+username+"光臨"); } public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { String username = (String) request.getAttribute("USERNAME"); response.setContentType("text/html;charset=UTF-8"); response.getWriter().write("歡迎"+username+"光臨"); } }
html
view.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>用戶登錄</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body>
<form action="/day07/Demo8" method="post">
<table border="1" align="center">
<caption>用戶登錄</caption>
<tr>
<th>用戶名</th>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="提交"/>
????
<input type="reset" value="重填"/>
</td>
</tr>
</table>
</form>
</body>
</html>
sucess.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>用戶登錄</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body>
登錄成功
</body>
</html>
fail.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>用戶登錄</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body>
登錄失敗
</body>
</html>
MVC設計模式-學習筆記