ClassNotFoundException - 如何在没有 Maven 的情况下使用外部库？

Question

As a result of my previous question I followed these steps to include Apache PDFbox without maven:

1. downloaded .jars from download site of PDFbox (all under Libraries of each subproject)
2. downloaded .jars from dependencies of PDFbox from maven repository (commons-logging and fontbox, but fontbox was already included in step 1)
3. placed the downloaded .jars in a folder ( C:\\PDFjars )
4. configured build path in eclispe (added all .jars as external libraries) It now looks like this:

My servlet:

package servlets;
// other imports    
import org.apache.pdfbox.pdmodel.PDDocument;

@WebServlet("/print")
public class PrintServlet extends HttpServlet {
    public PrintServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // From a PDFbox Tutorial

        //Creating PDF document object 
          PDDocument document = new PDDocument();    

          //Saving the document
          document.save("C:/PdfBox_Examples/my_doc.pdf");

          System.out.println("PDF created");  

          //Closing the document  
          document.close();

        doGet(request, response);
    }

}

So when I start my web project and call the function the should produce a simple PDF document, I get folloing error:

    Servlet.service() for servlet [servlets.PrintServlet] in context with path [/StaticsCalculator] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: org.apache.pdfbox.pdmodel.PDDocument
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1291)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
    at servlets.PrintServlet.doPost(PrintServlet.java:44)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    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)

Solution : I had to copy the .jars in WEB-INF/lib folder as well.

Answer 1

You can a) use a local maven repository and place the dependencies there. b) add the dependencies in the classpath of the application - that's basically what maven does for you.

Answer 2

Download the jar file by itself and add it to your code dependency. You can search for any Maven file on Maven Repository . If you're using Eclipse, just modify the build path to point to an external jar and give it the location of your jar. This will not take care of any dependencies your library requires, which leads into dependency hell where you'll have to read the pom and download each library manually.