servlet和JSP的使用

我已經創建了一個小應用程序，但是我在運行Tomcat服務器7中的一段代碼時遇到了問題。我想創建一個簡單的登錄頁面。我已經使用MySQL構建了一個數據庫。我的表單在瀏覽器中正確顯示，但是當我按下提交按鈕時，我收到了404錯誤。我使用過servlet和jsp。如果有人正在我的代碼下面看看，我將不勝感激。servlet和JSP的使用

LoginKlientiServlet.java：

package prorent.controllers; 
    import java.io.IOException; 
    import java.io.PrintWriter; 
    import java.sql.DriverManager; 
    import java.sql.ResultSet; 
    import java.sql.SQLException; 

import javax.servlet.RequestDispatcher; 
import javax.servlet.ServletException; 
import javax.servlet.annotation.WebServlet; 
//import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.HttpSession; 

import com.mysql.jdbc.Connection; 
import com.mysql.jdbc.PreparedStatement; 
import java.io.*; 
import javax.servlet.http.*; 
import javax.servlet.*; 
import java.sql.*; 


import prorent.DAO.LoginKlientiDAO; 
//@(name="LoginKlientiServlet", urlPatterns= {"/LoginKlientiServlet"}) 
public class LoginKlientiServlet extends HttpServlet{ 

private static final long serialVersionUID = 1L; 

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    response.setContentType("text/html"); 
    PrintWriter out = response.getWriter(); 
    String user = request.getParameter("username"); 
    String pass = request.getParameter("password"); 
    String repass = request.getParameter("repassword"); 
    try { 
     Class.forName("com.mysql.jdbc.Driver"); 
     Connection conn = (Connection) DriverManager.getConnection("jdbc:mysql://localhost:3306/pro", "root", "erida"); 
     PreparedStatement pst = (PreparedStatement) conn.prepareStatement("Select username,password, repassword from klienti where username=? and password=? and repassword=?"); 
     pst.setString(1, user); 
     pst.setString(2, pass); 
     pst.setString(2, repass); 
     ResultSet rs = pst.executeQuery(); 
     if (rs.next()) { 
      out.println("Correct login credentials"); 
     } 
     else { 
      out.println("Incorrect login credentials"); 
     } 
    } 
    catch (ClassNotFoundException | SQLException e) { 
     e.printStackTrace(); 
    } 
} 
}

LoginKlientiDAO.java

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
pageEncoding="ISO-8859-1"%> 
<html> 
    <head> 
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<title>Login Application</title> 
</head> 
    <body> 
    <form action="LoginKlientiServlet" method="post"> 
    <fieldset style="width: 300px"> 
     <legend> Login to App </legend> 
     <table> 
      <tr> 
       <td>User ID</td> 
       <td><input type="text" name="username" required="required" /></td> 
      </tr> 
      <tr> 
       <td>Password</td> 
       <td><input type="password" name="password" required="required" /></td> 
      </tr> 
      <tr> 
       <td>Repassword</td> 
       <td><input type="password" name="repassword" required="required" /></td> 
      </tr> 
      <tr> 
       <td><input type="submit" value="Login" /></td> 
      </tr> 
     </table> 
    </fieldset> 
</form>

的web.xml

<?xml version="1.0" encoding="UTF-8"?> 

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://java.sun.com/xml/ns/javaee"  xmlns:jsp="http://java.sun.com/xml/ns/javaee/jsp" 
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
metadata-complete="true" version="2.5"> 

<display-name>Jap me qera</display-name> 


<servlet> 

    <description /> 

    <display-name>LoginKlientiController</display-name> 

    <servlet-name>LoginKlienti-DAO</servlet-name> 

    <servlet-class>prorent.controllers.LoginKlientiServlet</servlet-class> 

</servlet> 



    <servlet-mapping> 

    <servlet-name>login-lista</servlet-name> 

    <url-pattern>/listalog</url-pattern> 



</servlet-mapping>

我的控制檯顯示此錯誤消息

 Jul 25, 2016 2:48:40 PM org.apache.catalina.core.AprLifecycleListener init 
    INFO: The APR based Apache Tomcat Native library which allows optimal  performance in production environments was not found on the java.library.path: C:\Program Files\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/bin/server;C:/Program Files/bin;C:/Program Files/lib/amd64;C:\Program Files\WinRAR;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\QuickTime\QTSystem\;C:\Program Files (x86)\Skype\Phone\;C:\Users\USER\AppData\Local\Temp\Rar$EX59.800\eclipse;;. 
    Jul 25, 2016 2:48:40 PM org.apache.tomcat.util.digester.SetPropertiesRule begin 
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:prorent' did not find a matching property. 
Jul 25, 2016 2:48:40 PM org.apache.coyote.AbstractProtocol init 
INFO: Initializing ProtocolHandler ["http-bio-8080"] 
Jul 25, 2016 2:48:40 PM org.apache.coyote.AbstractProtocol init 
INFO: Initializing ProtocolHandler ["ajp-bio-8009"] 
Jul 25, 2016 2:48:40 PM org.apache.catalina.startup.Catalina load 
INFO: Initialization processed in 899 ms 
Jul 25, 2016 2:48:40 PM org.apache.catalina.core.StandardService startInternal 
INFO: Starting service Catalina 
Jul 25, 2016 2:48:40 PM org.apache.catalina.core.StandardEngine startInternal 
INFO: Starting Servlet Engine: Apache Tomcat/7.0.47 
Jul 25, 2016 2:48:41 PM org.apache.catalina.util.SessionIdGenerator createSecureRandom 
INFO: Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [197] milliseconds. 
Jul 25, 2016 2:48:41 PM org.apache.coyote.AbstractProtocol start 
INFO: Starting ProtocolHandler ["http-bio-8080"] 
Jul 25, 2016 2:48:41 PM org.apache.coyote.AbstractProtocol start 
INFO: Starting ProtocolHandler ["ajp-bio-8009"] 
Jul 25, 2016 2:48:41 PM org.apache.catalina.startup.Catalina start 
INFO: Server startup in 1164 ms

預先感謝您！

來源

2016-07-25 Elly

表單將數據提交到網址/LoginKlientiServlet，但您沒有針對該網址格式的任何servlet映射。

也許你可以在你的web.xml中添加一個url模式，就像你有/listalog一樣。例如，

<servlet-mapping> 
    <servlet-name>LoginKlienti-DAO</servlet-name> 
    <url-pattern>/LoginKlientiServlet</url-pattern> 
</servlet-mapping>

來源

2016-07-25 14:28:46 Abubakkar

你的servlet映射似乎是錯誤的部署描述符（web.xml）

你可以找到更多關於如何你的servlet映射到應用here

正確代碼看起來應該像somethinf：

<servlet> 
    <servlet-name>LoginKlienti-DAO</servlet-name> 
    <servlet-path>prorent.controllers.LoginKlientiServlet</servlet-path> 
</servlet> 
<servlet-mapping> 
    <servlet-name>LoginKlienti-DAO</servlet-name> 
    <url-pattern>/LoginKlientiServlet</url-pattern> 
</servlet-mapping>

來源

2016-07-25 14:29:41 MaVRoSCy

我試過，但沒有任何變化 – Elly

似乎是一個錯誤 – Elly

你應該修正ÿ我們的servlet路徑指向你的servlet類。正如我提供的代碼，你的servlet應該在包'prorent.controllers'中。如果它不在那裏，你應該修復這個並選擇正確的包 – MaVRoSCy

servlet和JSP的使用

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