java支持servlet和JSP的使用
我已经创建了一个小应用程序，但在Tomcat server 7中运行一段代码时遇到了问题。我想创建一个简单的登录页面。我用MySQL建立了一个数据库。我的表单在浏览器中显示正确，但当我按下提交按钮时，出现404错误。我使用了servlet和jsp。如果有人查看我下面的代码，我将不胜感激
罗林克林蒂瑟夫莱特。爪哇：
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();
}
}
}
罗金利恩蒂多。爪哇
<%@ 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>
网络。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>
我的控制台显示此错误消息
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
提前谢谢
# 1 楼答案
部署描述符（web.xml）中的servlet映射似乎错误
您可以了解更多关于如何将servlet映射到应用程序here
正确的代码应该是这样的：