SQLiteのNullPointerExceptionエラー

Question

：

update.jsp：

<%@ page language="java" import="com.solly.CaliforniaWaterDataVisualizationJSPCode" %> 
<title>Updating database</title> 
<a href="index.html">Return to home page</a> 
<br> 
Updating database...<br> 
<pre> 
<% 
CaliforniaWaterDataVisualizationJSPCode.update(request, out); 
%> 
</pre> 

CaliforniaWaterDataVisualizationJSPCode.java：

package com.solly; 

import java.io.IOException; 
import java.io.InputStream; 
import java.net.URL; 
import java.net.URLConnection; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.SQLException; 

import javax.servlet.http.HttpServletRequest; 
import javax.servlet.jsp.JspWriter; 

import com.solly.parser.PSVParser; 

public abstract class CaliforniaWaterDataVisualizationJSPCode { 
    static public void update(HttpServletRequest request, JspWriter out) throws IOException, SQLException, ClassNotFoundException { 
     try(Connection dbConnection = DriverManager.getConnection("jdbc:sqlite:California_Water_Data.db")) { 
      if(request.getParameter("caldata-surface-toxic") != null) { 
       URL url = new URL("https://data.ca.gov/sites/default/files/Surface_Water_Toxicity_2001_2015.txt"); 
       URLConnection urlConnection = url.openConnection(); 
       try(InputStream inputStream = urlConnection.getInputStream()) { 
        byte[] data = new byte[urlConnection.getContentLength()]; 
        inputStream.read(data); 
        String content = new String(data); 
        PSVParser.parseFile(content); 
       } 
      } 
      out.println("Finished retrieving data from data.ca.gov's 2001 to 2015 surface water toxicity record<br>"); 
     } catch(Throwable e) { 
      out.println("Error: <br>" + e + "<br><br>" + "Stack trace: <br>"); 
      for(StackTraceElement element : e.getStackTrace()) { 
       out.println(element + "<br>"); 
      } 
      out.println("<br>Cause: <br>" + e.getCause()); 
     } 
    } 
} 

私は、Java EE 7を使用しています私はjava2s.comのSQLite JDBC 3.7.2のコンパイル済およびソースJAR（sqlite-jdbc-3.7.2.jarおよびsqlite-jdbc-3.7.2-sources.jar）をGlassFish 4で実行しています。 1.1ビルド1.私のコードはGitHubのgithub.com/dhDZsG9QfQK3VTiF5KOs/California_Water_Data_Visualizationにアクセスできます。私はgithub.com/dhDZsG9QfQK3VTiF5KOs/California_Water_Data_Visualization/issues/1でこれについてのGitHubの問題を作成しました。

スタックトレース：

org.sqlite.NestedDB$CausedSQLException.fillInStackTrace(NestedDB.java:649) 
java.lang.Throwable.(Throwable.java:250) 
java.lang.Exception.(Exception.java:54) 
java.sql.SQLException.(SQLException.java:140) 
org.sqlite.NestedDB$CausedSQLException.(NestedDB.java:626) 
org.sqlite.NestedDB._open(NestedDB.java:63) 
org.sqlite.DB.open(DB.java:86) 
org.sqlite.Conn.open(Conn.java:140) 
org.sqlite.Conn.(Conn.java:57) 
org.sqlite.JDBC.createConnection(JDBC.java:77) 
org.sqlite.JDBC.connect(JDBC.java:64) 
java.sql.DriverManager.getConnection(DriverManager.java:579) 
java.sql.DriverManager.getConnection(DriverManager.java:243) 
com.solly.CaliforniaWaterDataVisualizationJSPCode.update(CaliforniaWaterDataVisualizationJSPCode.java:18) 
org.apache.jsp.update_jsp._jspService(update_jsp.java:53) 
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111) 
javax.servlet.http.HttpServlet.service(HttpServlet.java:790) 
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:411) 
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:473) 
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:377) 
javax.servlet.http.HttpServlet.service(HttpServlet.java:790) 
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
java.lang.reflect.Method.invoke(Method.java:601) 
org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:323) 
org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:321) 
java.security.AccessController.doPrivileged(Native Method) 
javax.security.auth.Subject.doAsPrivileged(Subject.java:536) 
org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:356) 
org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:214) 
org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1676) 
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318) 
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160) 
org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734) 
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673) 
com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99) 
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174) 
org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416) 
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283) 
com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459) 
com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167) 
org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206) 
org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180) 
org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235) 
org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119) 
org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283) 
org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200) 
org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132) 
org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111) 
org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77) 
org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536) 
org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112) 
org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117) 
org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56) 
org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137) 
org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591) 
org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571) 
java.lang.Thread.run(Thread.java:722) 

Answer 1

私はtryブロックの前にDriverManager.registerDriver(new JDBC());を追加することによって、それを解決しました。私を刺激したのは、新しいエラーメッセージ（サーバーの再起動後）でした。「java.sql.SQLException：jdbc：sqlite：California_Water_Data.dbに適切なドライバが見つかりません」