使用外部罐当Eclipse朱诺EE的NoClassDefFoundError [英] Eclipse Juno EE NoClassDefFoundError when using external Jar

问题描述

我通过文件夹在我的日食动态webproject添加外部JAR - >属性 - >构建路径 - >库 - >添加外部罐子。

I added an external jar in my eclipse dynamic webproject via Folder -> properties -> build path -> Libraries -> add external jar.

在code是编译时工作正常。

The code is working fine on compile time.

package servlet;
import java.io.IOException;
import java.io.PrintWriter;

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

import org.apache.tika.Tika;

@WebServlet(name="UploadServlet", urlPatterns={"/uploadFile"})     // specify urlPattern for servlet
@MultipartConfig                       //Specify that this servlet will receive a multipart data
public class UploadServlet extends HttpServlet {

    protected void doPost(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException{
        Tika tika = new Tika();

        res.setContentType("text/html");
        PrintWriter writer = res.getWriter();
        writer.write(mediaType);
    }
}

我添加的Apache提卡但是当我运行我的应用程序。这些出现异常。

I added Apache Tika but when I run my application. these exception occured.

root cause 

java.lang.NoClassDefFoundError: org/apache/tika/Tika
    servlet.UploadServlet.doPost(UploadServlet.java:19)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)


root cause 

java.lang.ClassNotFoundException: org.apache.tika.Tika
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
    servlet.UploadServlet.doPost(UploadServlet.java:19)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

我使用Apache提卡，以确定哪些文件已被上传，我想如果一个文件是图像，或者用它来验证音频文件

I am using Apache Tika to determine what file has been upload, I want to use it for validating if a file is an image, or audio file

推荐答案

您忘了那个jar添加到部署大会页面。当你运行你的应用程序，因此NoClassDefFoundErrors这不是部署到服务器。

You forgot to add that jar to the Deployment Assembly page. It's not deployed to the server when you run your application, hence the NoClassDefFoundErrors.

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