Question

我在EC2实例的Glassfish4服务器上部署了一个JavaEE Web应用程序一切正常，但当我尝试添加日志记录功能时，我找不到日志。我创建了一个MyLogger静态类只是为了开始（我仍然需要学习很多关于日志记录的事情，我担心这可能是我失败的原因......）。这是代码

import java.io.IOException;
import java.util.logging.FileHandler;
import java.util.logging.Logger;
import java.util.logging.SimpleFormatter;

public class MyLogger {

    private final String LOG_FILENAME = "/tmp/app.log";

    private static Logger logger = Logger.getLogger("MyLogger");
    private static FileHandler fh;

    public MyLogger() {

        try {
            // This block configure the logger with handler and formatter
            fh = new FileHandler(LOG_FILENAME);
            logger.addHandler(fh);
            SimpleFormatter formatter = new SimpleFormatter();
            fh.setFormatter(formatter);

        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void logInfo(String msg) {
        logger.info(msg);
    }

    public static void logWarning(String msg) {
        logger.warning(msg);
    }

    public static void logSevere(String msg) {
        logger.severe(msg);
    }
}

这是使用MyLogger

的类

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;

/**
 * Servlet implementation class RequestsApi
 */
@WebServlet("/api/requests")
public class RequestsApi extends HttpServlet {
    private static final long serialVersionUID = 1L;

    // set the ArrayList where to put the offers that can satisfy
    // the request
    List<Offer> goodOffers;

    Request liftRequest;

    // The Bean for the requests
    @EJB
    RequestEJB requestEjb;

    // the Bean for the offers
    @EJB
    OfferEJB offerEjb;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public RequestsApi() {
        super();
        // TODO Auto-generated constructor stub
         goodOffers = new ArrayList<Offer>();
         liftRequest = new Request();
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        List<Request> listRequest = new ArrayList<Request>();

        String origin = request.getParameter("origin");
        String destination = request.getParameter("destination");

        if (origin != null) {
            Request liftRequest = new Request();
            liftRequest.setOrigin(origin);
            liftRequest.setDestination(destination);
            requestEjb.createRequest(liftRequest);
        }

        MyLogger.logSevere(origin + ", "+ destination);

        // get all the athletes in the DB
        listRequest = requestEjb.findRequests();

        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    List<Offer> offers = offerEjb.findOffers();
                    for (Offer offer : offers)
                        if (isGood(offer))
                            goodOffers.add(offer);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
        });

        thread.start();

        // create the JSON file
        JSONArray array = new JSONArray(listRequest);
        response.getWriter().append(array.toString());
    }

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

        final String origin = request.getParameter("origin");
        final String destination = request.getParameter("destination");
        final String username = request.getParameter("username");

        liftRequest.setOrigin(origin);
        liftRequest.setDestination(destination);
        liftRequest.setRequesterUsername(username);
        requestEjb.createRequest(liftRequest);

        MyLogger.logInfo(username + ": " + origin + ", "+ destination);

        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    List<Offer> offers = offerEjb.findOffers();
                    for (Offer offer : offers)
                        if (isGood(offer))
                            goodOffers.add(offer);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
        });

        thread.start();
    }

    public boolean isGood(Offer offer) throws Exception {

        return true;
    }

}

servlet在回答网络浏览器方面运行良好，但我不知道如何获取我的日志文件。

我认为我应该在EC2实例的/ tmp目录中找到我的日志文件，但事实并非如此。

我的记录器实现有什么问题，或者我是否需要注意使用特定的日志记录配置来管理EC2中的文件？

新信息 我在我的PC上使用独立的Java应用程序尝试了相同的方法并且它可以工作它实际上似乎是管理EC2实例上的文件的问题

新信息 关于EC2日志记录与独立的Java应用程序一起正常工作。所以问题不在于EC2，而在于如何在JavaEE Web应用程序中管理日志记录

新信息 将MyLogger的内容放入RequestsApi一切正常。

Answer 1

我发现了问题：它是关于静态方法和构造函数的基本知识:-（
我认为只有在引用类时，即使调用静态方法并且不需要对象实例，也会调用构造函数。
这不是真的，所以没有添加到记录器的处理程序。

使用MyLogger类和静态方法时记录不起作用

1 个答案: