java.lang.ClassNotFoundException與TomcatWAR檔案

我正在嘗試為我目前正在處理的專案制作一個簡單的 REST API，以簡化我每天必須完成的任務，當我到達托管它的地方時，我遇到了 500 服務器錯誤. 查看（tomcat home dir）/logs/localhost.2021-10-22.log中的日志，我發現了這個錯誤：

22-Oct-2021 21:33:58.974 SEVERE [http-nio-13760-exec-64] org.apache.catalina.core.StandardWrapperValve.invoke Allocate exception for servlet [OrderServlet]
java.lang.ClassNotFoundException: api.OrderServlet
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1407)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1215)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:538)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:519)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1070)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:788)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:128)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1722)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

我還有這里“不存在”的類的代碼：

package api;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONObject;

import data.Order;

public class OrderServlet extends HttpServlet {
    
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
        
        String requestUrl = request.getRequestURI();
        String id = requestUrl.substring("cafe/orders/".length());
        
        
        Order order = Requests.getInstance().getOrder(id);
        
        if (order != null) {
            String json = "{\n";
            json  = "\"id\": "   JSONObject.quote(order.getID())   ",\n";
            json  = "\"id\": "   JSONObject.quote(order.getName())   ",\n";
            json  = "\"id\": "   JSONObject.quote(String.valueOf(order.getTime()))   ",\n";
            //various parameters removed to prevent abuse in the future (I'm looking at you, Dax)
            //I'd rather not have a coffee order show up with a comically large amount of creamers in it
            json  = "};";
            response.getOutputStream().println(json);
        } else {
            //order was not found
            response.sendError(404);
        }
    }
    
    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse responce) throws IOException, ServletException {
        String id = request.getParameter("id");
        String name = request.getParameter("name");
        int time = Integer.parseInt(request.getParameter("time"));
        //various parameters removed
        
        Requests.getInstance().putOrder(new Order(id, name, time, type, //various parameters removed
));
    }

}

我已經檢查過該類是否確實存在，我已經嘗試重建類，作為非編譯檔案匯入并處理 web.xml，并且我已經檢查過構建路徑中沒有隨機的 jre6 庫（從這里）。我沒有使用 Maven，Tomcat 能夠很好地加載檔案和管理器。如何讓 Tomcat 能夠識別該類？

uj5u.com熱心網友回復：

看起來該檔案沒有從 Eclipse 正確匯出，因此手動修復了問題。

編輯：原來問題是我的源檔案夾不是 Eclipse 試圖匯出的檔案夾。進入屬性> 部署程式集并更改源檔案夾修復它（感謝@Piotr P Karwasz！）

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