找不到HTTP 404（未找到Servlet）

Question

我是一名学生，正在学习使用jsp和servlet构建Web应用程序。我的Web应用程序项目自一个月以来工作正常，但今天突然表现得很奇怪。当我提交我的jsp页面时，它无法找到我的servlet。我使用 servlet注释来映射请求。

以下是我的jsp： -

<form name=registration_form action="<%=application.getContextPath() %>/Registration" method="post">  
    First Name:</td><td><input type="text" name="firstName" required/></td></tr> 
    </form>

以下是我的Servlet： -

package servlets;
    @WebServlet("/Registration")
    public class Registration extends HttpServlet {
        private static final long serialVersionUID = 1L;
        public Registration() {
            super();
        }

        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            // TODO Auto-generated method stub
        }

        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            String firstName=request.getParameter("firstName"); 
            System.out.println(firstName);
        }
    }

以下是我的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: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_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>Login</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

以下是我的项目层次结构： -

以下是错误： -

HTTP Status 404 - /Login/Registration
type Status report

message /Login/Registration

description The requested resource is not available.

Apache Tomcat/7.0.47 

以下是我的控制台日志： -

Mar 11, 2014 11:30:33 AM 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 (x86)\Java\jre7\bin;C:\windows\Sun\Java\bin;C:\windows\system32;C:\windows;C:/Program Files (x86)/Java/jdk1.6.0_17/bin/../jre/bin/client;C:/Program Files (x86)/Java/jdk1.6.0_17/bin/../jre/bin;C:/Program Files (x86)/Java/jdk1.6.0_17/bin/../jre/lib/i386;C:\Program Files (x86)\PC Connectivity Solution\;C:\Program Files (x86)\Java\jdk1.6.0_17\bin;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live;C:\windows\system32;C:\windows;C:\windows\System32\Wbem;C:\windows\System32\WindowsPowerShell\v1.0\;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;c:\Program Files (x86)\Common Files\Roxio Shared\DLLShared\;c:\Program Files (x86)\Common Files\Roxio Shared\OEM\DLLShared\;c:\Program Files (x86)\Common Files\Roxio Shared\OEM\DLLShared\;c:\Program Files (x86)\Common Files\Roxio Shared\OEM\12.0\DLLShared\;c:\Program Files (x86)\Roxio\OEM\AudioCore\;C:\Program Files (x86)\Windows Live\Shared;C:\Program Files (x86)\Microsoft SQL Server\90\Tools\binn\;C:\Program Files (x86)\Android\android-sdk;C:\Program Files (x86)\Java\jdk1.6.0_17\bin;C:\Program Files (x86)\MySQL\MySQL Utilities 1.3.4\;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x86;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x64;D:\mongodb\bin;D:\development tools\apache-maven-3.1.1-bin\apache-maven-3.1.1\bin;C:\Program Files (x86)\Google\google_appengine\;D:\development tools\eclipse;;.
Mar 11, 2014 11:30:33 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:Login' did not find a matching property.
Mar 11, 2014 11:30:34 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8080"]
Mar 11, 2014 11:30:34 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
Mar 11, 2014 11:30:34 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 1071 ms
Mar 11, 2014 11:30:34 AM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Mar 11, 2014 11:30:34 AM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.47
Mar 11, 2014 11:30:35 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8080"]
Mar 11, 2014 11:30:35 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
Mar 11, 2014 11:30:35 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 1463 ms

Answer 1

我也遇到了这个问题。 每当我们删除一个tomcat服务器并在没有构建类路径的情况下运行我们的项目并清理和构建该项目时，我们就会遇到这种类型的异常。

因此，构建项目类路径。 您的项目的Goto属性然后选择=＆gt; Java Build Path =＆gt;订单和出口。 选择所有类路径。

Answer 2

您的Servlet路径为/Registration，但您的请求指向/Login/Registration。

您需要执行表单的操作属性。

action="${pageContext.request.contextPath}/Registration"

或

action="/Registration"

Answer 3

在jsp操作页面中使用此格式：

action="/Registration"

和网页：

<servlet>
<servlet-name>Registration</servlet-name>
 <servlet-class>packagename.Registration</servlet-class>
</servlet> 
<servlet-mapping>
<servlet-name>Registration</servlet-name>
 <url-pattern>/Registration</url-pattern>
</servlet-mapping>

follow this