<%@page import="java.util.Date"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<jsp:useBean id="user" scope="request" class="jsp.demo.entity.User"></jsp:useBean>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>hello</title>
</head>
<body>
<%
if(user.getName() !=null){
if(user.getName()==""){
out.println("用戶名不能爲空！");
}else{
%>
你好：<%=user.getName() %>
<% }} %>
<form action="/testweb/Userlogin" method="post">
<input type="text" name="name" value="">
<input type="submit" name="submit" value="提交" >
</form>
</body>
</html>2.User類
package jsp.demo.entity;
/**
* User Bean爲了封裝jsp表單中的數據
* @author Administrator
*
*/
public class User {
private String name;//用戶名
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
package jsp.servlet.demo;
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 jsp.demo.entity.User;
/**
* Servlet implementation class Userlogin
*/
public class Userlogin extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Userlogin() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 獲取輸入信息
String name = request.getParameter("name");
User user = new User();
user.setName(name);
//將user添加到response對象中
request.setAttribute("user", user);
//將請求轉向指定的頁面
RequestDispatcher rdt = request.getRequestDispatcher("/jsp/login.jsp");
rdt.forward(request, response);
}
}
<servlet>
<description></description>
<display-name>Userlogin</display-name>
<servlet-name>Userlogin</servlet-name>
<servlet-class>jsp.servlet.demo.Userlogin</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Userlogin</servlet-name>
<url-pattern>/Userlogin</url-pattern>
</servlet-mapping>ps：1.注意頁面action請求路徑和web中的<url-pattern>/Userlogin</url-pattern>關係
2.請求的method和servlet中的處理方法對應（當然可以用service(HttpServletRequest arg0, HttpServletResponse arg1)方式，可以避免不對應情況）