org.apache.catalina.core.StandardWrapperValveを呼び出すSEVERE：サーブレットのServlet.service（）

私は単純な銀行業務に取り組んでおり、私は初期段階にあります。私が欲しいのは、register.html とRegisterServlet.javaページを通して顧客情報をデータベースに保存することです。しかし残念なことに、StatndardWrapperValve呼び出しエラー（NullPointerException）というエラーが発生して動作を停止しました。私はこの問題を最後の3日間から解決しようとしていますが、解決策はありません。私は私のGitHubリンクも含めてGitHub Jdbc Banking Project Linkであり、jarファイルにはojdbc6のみが含まれています。私のコードは、tryブロック行（ps = con.prepareStatement（ "name、email、mobile、city、dob）の値（？、？、？、？、？）助けて。org.apache.catalina.core.StandardWrapperValveを呼び出すSEVERE：サーブレットのServlet.service（）

My pages 
1. login.html 
2. register.html 
3. RegisterServlet.java 
4. DBConnectionManager.java 
5. web.xml

register.html

<!DOCTYPE html> 
<html> 
<head> 
<meta charset="ISO-8859-1"> 
<title>Insert title here</title> 
</head> 
<body> 

<h3 align="center">Customer Registration Page</h3> 
<form action="RegisterServletPath" method="post"> 
<table align="center"> 
    <tr> 
     <td>Customer Name</td> 
     <td><input type="text" name="name"></td> 
    </tr> 

    <tr> 
     <td>Email</td> 
     <td><input type="text" name="email"></td> 
    </tr> 

    <tr> 
     <td>Mobile</td> 
     <td><input type="text" name="mobile"></td> 
    </tr> 

    <tr> 
     <td>City</td> 
     <td><input type="text" name="city"></td> 
    </tr> 

    <tr> 
     <td>DOB</td> 
     <td><input type="date" name="dob"></td> 
    </tr> 

    <tr> 
     <td></td> 
     <td><input type="submit" value="Register"></td> 
    </tr> 

</table> 
</form> 

</body> 
</html>

RegisterServlet.java

import java.io.IOException; 
import java.io.PrintWriter; 
import java.sql.Connection; 
import java.sql.PreparedStatement; 
import java.sql.SQLException; 

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

/** 
* Servlet implementation class RegisterServlet 
*/ 
//@WebServlet("/RegisterServletPath") 
@WebServlet(name="RegisterServlet", urlPatterns={"/RegisterServletPath"}) 
public class RegisterServlet extends HttpServlet { 
    private static final long serialVersionUID = 1L; 

    /** 
    * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 
    */ 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
     // TODO Auto-generated method stub 
     response.getWriter().append("Served at: ").append(request.getContextPath()); 
     System.out.println("Inide doGet method"); 
    } 

    /** 
    * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 
    */ 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 

     System.out.println("Inside doPost method"); 
     PrintWriter out = response.getWriter(); 
     out.print("<html><h3>It is coming from RegisterServlet.java</h3></html>"); 
     String name = request.getParameter("name"); 
     String email = request.getParameter("email"); 
     String mobile = request.getParameter("mobile"); 
     String city = request.getParameter("city"); 
     String dob = request.getParameter("dob"); 

     /*write the logic for input validation*/ 
     String errorMsg = null; 
     if(name == null || name.equals("")) { 
      errorMsg = "Name can't be empty"; 
     } 
     if(email == null || email.equals("")) { 
      errorMsg = "Email can't be empty"; 
     } 
     if(mobile == null || mobile.equals("")) { 
      errorMsg = "Mobile number can't be empty"; 
     } 
     if(city == null || city.equals("")) { 
      errorMsg = "City name can't be empty"; 
     } 
     if(dob == null || dob.equals("")) { 
      errorMsg = "Date of birth can't be empty"; 
     } 

     System.out.println("Line 64"); 

     //when the text field is not null, this code statement won't run 
     if(errorMsg != null) { 
      System.out.println("Line 67"); 
      RequestDispatcher rd = getServletContext().getRequestDispatcher("/register.html"); 
      PrintWriter out1 = response.getWriter(); 
      out1.println("<font color=red>" +errorMsg+"</font>"); 
      rd.include(request, response); 
     } 

    // System.out.println("Line 73"); 
     else { 
      System.out.println("Line 73"); 
      Connection con = (Connection)getServletContext().getAttribute("DBConnection"); 
      PreparedStatement ps = null; 
      System.out.println("Line 79"); 


      try{ 
       System.out.println("Line 81"); 
       ps = con.prepareStatement("insert into customers(name,email,mobile,city,dob) values (?,?,?,?,?)"); 
       System.out.println("Line 82"); 
       ps.setString(1, name); 
       ps.setString(2, email); 
       ps.setString(3, mobile); 
       ps.setString(4, city); 
       ps.setString(5, dob); 
       System.out.println("Line 87"); 
       ps.execute(); 

       //forward to login page to login 
       RequestDispatcher rd = getServletContext().getRequestDispatcher("/login.html"); 
       PrintWriter out1 = response.getWriter(); 
       out1.println("<font color=green>Registration Successful, please login.</font>"); 
       rd.include(request, response); 

      } 
      catch(SQLException e) { 
       e.printStackTrace(); 
       //logger.error("Database connection problem"); 
       throw new ServletException("DB Connection Problem"); 
      } 
      finally { 
       try { 
        ps.close(); 
       } 
       catch(SQLException e) { 
        System.out.println("Inside second catch block"); 
        //logger.error("SQLException is closing PreparedStatement"); 
       } 
      } 
     } 


     //doGet(request, response); 
    } 


}

DBConnectionManager.java

あなたは完全に掲載している場合、私はあなたが必ずサーブレットコンテキストに接続していない設定されているプロジェクト内のどこにでも見ることができません

web.xmlの

<?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" 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>JDBC Banking Project</display-name> 
     <welcome-file-list> 
     <welcome-file>register.html</welcome-file> 
     </welcome-file-list> 

     <context-param> 
     <param-name>username</param-name> 
     <param-value>system</param-value> 
     </context-param> 
     <context-param> 
     <param-name>password</param-name> 
     <param-value>123456</param-value> 
     </context-param> 
     <context-param> 
     <param-name>dbURL</param-name> 
     <param-value>jdbc:oracle:thin:@localhost:1521:xe</param-value> 
     </context-param> 
    </web-app>

エラーコンソール

May 03, 2017 1:02:28 PM org.apache.tomcat.util.digester.SetPropertiesRule begin 
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:Hello World' did not find a matching property. 
May 03, 2017 1:02:28 PM org.apache.tomcat.util.digester.SetPropertiesRule begin 
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:JDBC Banking Project' did not find a matching property. 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Server version:  Apache Tomcat/7.0.69 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Server built:   Apr 11 2016 07:57:09 UTC 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Server number:   7.0.69.0 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: OS Name:    Windows 8.1 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: OS Version:   6.3 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Architecture:   amd64 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Java Home:    C:\Program Files\Java\jre7 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: JVM Version:   1.7.0_79-b15 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: JVM Vendor:   Oracle Corporation 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: CATALINA_BASE:   D:\Eclipse Workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: CATALINA_HOME:   C:\Program Files\Apache Software Foundation\Tomcat 7.0 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Command line argument: -Dcatalina.base=D:\Eclipse Workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Command line argument: -Dcatalina.home=C:\Program Files\Apache Software Foundation\Tomcat 7.0 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Command line argument: -Dwtp.deploy=D:\Eclipse Workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Command line argument: -Djava.endorsed.dirs=C:\Program Files\Apache Software Foundation\Tomcat 7.0\endorsed 
May 03, 2017 1:02:28 PM org.apache.catalina.startup.VersionLoggerListener log 
INFO: Command line argument: -Dfile.encoding=Cp1252 
May 03, 2017 1:02:28 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent 
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\Java\jre7\bin;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;D:\app\Shital\product\11.2.0\dbhome_1\bin;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x86;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x64;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\Program Files (x86)\QuickTime Alternative\QTSystem;C:\Program Files\Java\jdk1.7.0_79\bin;C:\Program Files\Java\jdk1.7.0_79\jre\lib;. 
May 03, 2017 1:02:29 PM org.apache.coyote.AbstractProtocol init 
INFO: Initializing ProtocolHandler ["http-bio-8080"] 
May 03, 2017 1:02:29 PM org.apache.coyote.AbstractProtocol init 
INFO: Initializing ProtocolHandler ["ajp-bio-8009"] 
May 03, 2017 1:02:29 PM org.apache.catalina.startup.Catalina load 
INFO: Initialization processed in 924 ms 
May 03, 2017 1:02:29 PM org.apache.catalina.core.StandardService startInternal 
INFO: Starting service Catalina 
May 03, 2017 1:02:29 PM org.apache.catalina.core.StandardEngine startInternal 
INFO: Starting Servlet Engine: Apache Tomcat/7.0.69 
May 03, 2017 1:02:29 PM org.apache.coyote.AbstractProtocol start 
INFO: Starting ProtocolHandler ["http-bio-8080"] 
May 03, 2017 1:02:29 PM org.apache.coyote.AbstractProtocol start 
INFO: Starting ProtocolHandler ["ajp-bio-8009"] 
May 03, 2017 1:02:29 PM org.apache.catalina.startup.Catalina start 
INFO: Server startup in 907 ms 
Inside doPost method 
Line 64 
Line 67 
Inside doPost method 
Line 64 
Line 73 
Line 79 
Line 81 
May 03, 2017 1:03:03 PM org.apache.catalina.core.StandardWrapperValve invoke 
SEVERE: Servlet.service() for servlet [RegisterServlet] in context with path [/JDBC_Banking_Project] threw exception 
java.lang.NullPointerException at RegisterServlet.doPost(RegisterServlet.java:110) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650) 
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) 
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) 
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) 
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) 
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) 
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505) 
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169) 
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) 
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956) 
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) 
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:436) 
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1078) 
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625) 
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) 
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
at java.lang.Thread.run(Unknown Source)

出典

2017-05-03 Lalit Kumar

ソースコード。 SQLExceptionのcatch節でキャッチすることができない場合NullPointerException

ps = con.prepareStatement("insert into customers(name,email,mobile,city,dob) values (?,?,?,?,?)");

を投げる行の下

Connection con = (Connection)getServletContext().getAttribute("DBConnection");

。が接続を終了しようとするとブロックします。 NullPointerExceptionがスローされます。

出典

2017-05-03 08:14:07 khurram

ねえ、私はこのブログ記事[http://www.journaldev.com/1997/servlet-jdbc-database-connection-example]を参照していますが、すべてのファイルを作成していません。私は最初の基本的なステップをやりたかっただけです。あなたは上記のリンクを見て、私が逃しているもので私を助けてくださいますか？すべてのソースコードを提供して、login.htmlを空白にしておいた。 –

私はgitのコードを参照すると、あなたのコードからAppContextListenerが見つからない。 – khurram

こんにちは、私は私のプロジェクトでAppcontextListener.javaを追加しましたが、それでも同じ出力を与えています。私のGitHubリンクをもう一度チェックしてください。それは私のために非常に役立つでしょう。 –

org.apache.catalina.core.StandardWrapperValveを呼び出すSEVERE：サーブレットのServlet.service（）

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