Question

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class TestServlets extends HttpServlet {

private static final long serialVersionUID = 1L;

public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws IOException {
    doPost(request, response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();

    out.println("Hello<br/>");

    boolean isMultipartContent = ServletFileUpload
            .isMultipartContent(request);
    if (!isMultipartContent) {
        out.println("You are not trying to upload<br/>");
        return;
    }
    out.println("You are trying to upload<br/>");

    FileItemFactory factory = new DiskFileItemFactory();
    ServletFileUpload upload = new ServletFileUpload(factory);
    try {
        List<FileItem> fields = upload.parseRequest(request);
        out.println("Number of fields: " + fields.size() + "<br/><br/>");
        Iterator<FileItem> it = fields.iterator();
        if (!it.hasNext()) {
            out.println("No fields found");
            return;
        }
        out.println("<table border=\"1\">");
        while (it.hasNext()) {
            out.println("<tr>");
            FileItem fileItem = it.next();
            boolean isFormField = fileItem.isFormField();
            if (isFormField) {
                out.println("<td>regular form field</td><td>FIELD NAME: "
                        + fileItem.getFieldName() + "<br/>STRING: "
                        + fileItem.getString());
                out.println("</td>");
            } else {
                out.println("<td>file form field</td><td>FIELD NAME: "
                        + fileItem.getFieldName() + "<br/>STRING: "
                        + fileItem.getString() + "<br/>NAME: "
                        + fileItem.getName() + "<br/>CONTENT TYPE: "
                        + fileItem.getContentType()                
                                                    +"<br/>SIZE(BYTES): "
                        + fileItem.getSize() + "<br/>TO STRING: "
                        + fileItem.toString());
                out.println("</td>");
            }
            out.println("</tr>");
        }
        out.println("</table>");
    } catch (FileUploadException e) {
        e.printStackTrace();
    }
}
}

错误代码

 >Mar 27, 2014 2:28:00 PM org.apache.catalina.core.StandardWrapperValve invoke
 >SEVERE: Servlet.service() for servlet [TestServlets] in context with path [/First] threwexception >[Servlet execution threw an exception] with root cause
    >java.lang.ClassNotFoundException: javax.servlet.http.HttpServletRequest
    >   at java.net.URLClassLoader$1.run(Unknown Source)
    >   at java.net.URLClassLoader$1.run(Unknown Source)
    >   at java.security.AccessController.doPrivileged(Native Method)
    >   at java.net.URLClassLoader.findClass(Unknown Source)
    >   at java.lang.ClassLoader.loadClass(Unknown Source)
    >   at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    >   at java.lang.ClassLoader.loadClass(Unknown Source)
    >   at org.apache.commons.fileupload.servlet.ServletFileUpload.
    >              isMultipartContent(ServletFileUpload.java:68)
    >   at TestServlets.doPost(TestServlets.java:31)
    >   at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    >   at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    >   at org.apache.catalina.core.ApplicationFilterChain.
    >          internalDoFilter(ApplicationFilterChain.java:305)
    >   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    >   at LogFilter.doFilter(LogFilter.java:35)
    >   at org.apache.catalina.core.ApplicationFilterChain.
    >             internalDoFilter(ApplicationFilterChain.java:243)
    >   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    >   at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
    >   at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    >   at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    >   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    >   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    >   at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    >   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    >   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    >   at org.apache.coyote.http11.AbstractHttp11Processor.
    >               process(AbstractHttp11Processor.java:999)
    >   at org.apache.coyote.AbstractProtocol$
    >               AbstractConnectionHandler.process(AbstractProtocol.java:565)
    >   at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1812)
    >   at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    >   at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    >   at java.lang.Thread.run(Unknown Source)

Answer 1

您忘了添加apache common fileupload jar 。 http://apache.mirrors.lucidnetworks.net//commons/fileupload/binaries/commons-fileupload-1.3.1-bin.zip

下载并添加您的类路径。如果还没有工作，请查看 servlet-api.jar

http://mirrors.ibiblio.org/pub/mirrors/maven/javax.servlet/jars/servlet-api-2.3.jar

我试图运行servlet，上传文件，但得到以下错误

1 个答案: