Question

我想在将文件上传到我在localhost上运行的服务器时获得java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream。这是我正在使用的servlet：

@WebServlet("/UploadServlet")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

private String UPLOAD_DIRECTORY = "~/EclipseProjects/DocSearch/uploads";

/**
 * @see HttpServlet#HttpServlet()
 */
public UploadServlet() {
    super();
}

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

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    if(ServletFileUpload.isMultipartContent(request)) {
        try {
            List<FileItem> multiparts = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);
            for(FileItem item: multiparts) {
                if(!item.isFormField()) {
                    String name = new File(item.getName()).getName();
                    item.write(new File(UPLOAD_DIRECTORY + File.separator + name));
                }
            }
            request.setAttribute("message", "File uploaded successfully");
        } catch (Exception ex) {
            request.setAttribute("message", "File upload failed due to: " + ex);
        }
    } else {
        request.setAttribute("message", "Sorry this servlet only handles file upload requests");
    }
    request.getRequestDispatcher("/result.jsp").forward(request, response);
}

}

我已经将commons-fileupload-1.2.2.jar添加到WEB-INF / lib文件夹中。我尝试创建一个新服务器并在其上运行项目，尝试从不同来源重新下载jar文件，但它们似乎都没有解决我的问题。

注意：

我已经经历过：

Answer 1

您必须将commons-fileupload.jar包含在项目依赖库文件夹中。

从官方网站http://commons.apache.org/proper/commons-fileupload/download_fileupload.cgi或maven网站获取commons-fileupload.jar：http://mvnrepository.com/artifact/commons-fileupload/commons-fileupload/1.3.1

如果您使用maven将此依赖项添加到pom.xml：

 <dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>

java.lang.NoClassDefFoundError：org / apache / commons / io / output / DeferredFileOutputStream

1 个答案: