Java Bean调用Java函数并将其传递给Jsp [英] Java Bean calling Java function and passing it to Jsp
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问题描述
大家好，我有一个LoginServlet，它具有可以登录用户的功能，但是我有一个带有要使用的样式的jsp页面.我不确定如何在我的login.jsp中使用我的LoginServlet中的功能
hi all I have a LoginServlet that has the functionality to log in a user however I have a jsp page with the styling I'd to use. I am unsure how I can use the functionality from my LoginServlet in my login.jsp
这是我用于LoginServlet的全部代码，我知道我已经编码显示一个页面，但是我需要使用此jsp页面来显示.这是我得到的单项分配，它是我们使用JSP进行显示的要求的一部分.
here is the entirety of my code for the LoginServlet, I am aware I have coded to display a page but I need to use this jsp page to display. This is a uni assignment I have been given and it's part of the requirement that we use JSP for display.
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
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 javax.servlet.RequestDispatcher;
/**
* Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
private void sendLoginForm(HttpServletResponse response,
boolean withErrorMessage)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Login</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<CENTER>");
if (withErrorMessage)
out.println("Login failed. Please try again.<BR>");
out.println("<BR>");
out.println("<BR><H2>Login Page</H2>");
out.println("<BR>");
out.println("<BR>Please enter your user name and password.");
out.println("<BR>");
out.println("<BR><FORM METHOD=POST>");
out.println("<TABLE>");
out.println("<TR>");
out.println("<TD>User Name:</TD>");
out.println("<TD><INPUT TYPE=TEXT NAME=uniid></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Password:</TD>");
out.println("<TD><INPUT TYPE=PASSWORD NAME=password></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD ALIGN=RIGHT COLSPAN=2>");
out.println("<INPUT TYPE=SUBMIT VALUE=Login></TD>");
out.println("</TR>");
out.println("</TABLE>");
out.println("</FORM>");
out.println("</CENTER>");
out.println("</BODY>");
out.println("</HTML>");
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
sendLoginForm(response, false);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String uniid = request.getParameter("uniid");
String password = request.getParameter("password");
if (login(uniid, password)) {
/*RequestDispatcher rd =
request.getRequestDispatcher("AnotherServlet");
rd.forward(request, response); */
response.sendRedirect("home_student.jsp");
}
else {
sendLoginForm(response, true);
}
}
boolean login(String uniid, String password) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/wae","root","");
System.out.println("got connection");
Statement s = con.createStatement();
String sql = "SELECT uniid FROM user" +
" WHERE uniid='" + uniid + "'" +
" AND password='" + password + "'";
ResultSet rs = s.executeQuery(sql);
if (rs.next()) {
return true;
}
rs.close();
s.close();
con.close();
}
catch (ClassNotFoundException e) {
System.out.println(e.toString());
}
catch (SQLException e) {
System.out.println(e.toString());
}
catch (Exception e) {
System.out.println(e.toString());
}
return false;
}
}
这是我的jsp页面
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Mars University Lab System</title>
<link rel="stylesheet" href="style.css" type="text/css" media="screen">
</head>
<body>
<jsp:include page="header.jsp"/>
<tr>
<td>
</td>
</tr>
<tr>
<td>
<div id = "centrecontent">
<table border="0" cellpadding="2">
<tr>
<td width="500px" align="center">
<br>
<font size="5">Welcome to <i>The Department of <br>Rocket Science</i> Lab System<br></font>
<br>
For <b>Students</b> you can enrol in labs<br> and manage the labs you're enrolled in.<br><br>
For <b>Tutors</b> you can view the labs<br> you're teaching and record attendence.<br><br>
For <b>Lecturers</b> you can create and<br> manage lab classes, register Tutors and<br> assign those Tutors to labs.<br><br>
</td>
<td width="500px">
<table border="0" align="center">
<tr>
<td align="center">
<table border="0" align="center">
<tr> <br><br><b>Existing Member? <br>Sign In Here!</b><br>
<td align="right">
<form name ="login" METHOD=POST ACTION="SaveSession.jsp">
Username: <input type="text" name="username"/><br />
Password: <input type="password" name="pword"/><br />
<input type=SUBMIT value="Login" name="Submit" />
</td>
</tr>
</table>
<br><br><br><br>
<form name="search_cat_bar" method="get" action="">
<input type="hidden" name="dff_view" value="grid">
Search:<input type="text" name="dff_keyword" size="30" maxlength="50"> <br>in
<select name="dff_cat1num" size="1">
<option value="-1">All Subjects
<option value="-2">--------------
<option value="101">CSE2ICE
<option value="193">CSE3PRA
<option value="193">CSE3PRB
<option value="193">CSE3WAE
</select>
<input type="submit" value="Find">
</form>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table>
<tr>
</tr>
</table>
</div>
<jsp:include page="footer.jsp"/>
</body>
</html>
我希望login.jsp页面调用我的LoginServlet来实现登录功能.
I'd like the login.jsp page to call my LoginServlet for the login functions.
推荐答案
您可以通过以下方式调用servlet: web.xml
You can call servlet by this way: web.xml
<servlet>
<servlet-name>UserLogin</servlet-name>
<servlet-class>com.servlet.LoginServlet</servlet-class>//full class path
</servlet>
<servlet-mapping>
<servlet-name>UserLogin</servlet-name>
<url-pattern>/servlet/login</url-pattern>
</servlet-mapping>
login.jsp
login.jsp
<form name="login" action="<%=request.getContextPath()%>/servlet/login" method="post">
</form>
Servlet: 登录检查，您也可以将错误消息仅发送到登录页面并显示类似消息，
Servlet: Login check and also you can send just error message to login page and display message like,
res.sendRedirect(req.getContextPath()+"/webpages/login.jsp?login=failed");
在login.jsp中，您可以检索参数request.getParameter("login")并显示正确的消息
And in login.jsp you can retrieve parameter request.getParameter("login") and display proper message
这篇关于Java Bean调用Java函数并将其传递给Jsp的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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