java - 在 Apache Tomcat 上运行时出现 FileNotFound 异常？

Question

我有一个使用 Apache Tomcat 6.0 的简单 Web 应用程序。我正在尝试从路径“resources/mysql.properties”读取属性文件。这里的“resources”文件夹在“src”文件夹之外。当我尝试将项目作为 Java 应用程序运行时，它工作正常。但是当我在服务器上运行它时它会抛出 FileNotFoundException。

这是我在控制台上运行的带有 main 的 Java 代码。

package com.jm.test;

import com.jm.util.PropertyUtil;

public class CodeTester {

    public static void main(String[] args) {
            System.out.println(PropertyUtil.getDBPropertyValue("driver"));
    }

}

这是PropertyUtil.Java文件的代码。

    /**
     * 
     */
    package com.jm.util;

    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.MissingResourceException;
    import java.util.Properties;

    import org.apache.log4j.Logger;

    /**
     * @author Jaydeep Ranipa
     *
     */
    public class PropertyUtil {
        public static final Logger log = Logger.getLogger(PropertyUtil.class);
        private static final String resourceDir = "resources";

        private PropertyUtil() {
        }

        private static Properties loadProperties(String fileName) throws IOException, FileNotFoundException {
            System.out.println("filename: "+fileName);
            InputStream fileStream = new FileInputStream(new File(fileName));
            Properties props = new Properties();
            props.load(fileStream);
            return props;
        }

        public static String getDBPropertyValue(String key) {
            Properties prop = null;
            String value = "";
            String fileName = "localmysql.properties";

            try {
                prop = loadProperties(resourceDir + "/" + fileName);
                value = prop.getProperty(key);
                if (value == null) {
                    throw new MissingResourceException("Property not found.", "DATABASE", key);
                }
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                System.out.println("properties file not found");
                e.printStackTrace();
                log.error("Properties file <<<"+resourceDir + "/" + fileName +">>> not found.");
                value = "Error occured.";
            } catch (IOException e) {
                // TODO Auto-generated catch block
                System.out.println("properties file reading failed");
        log.error("Properties file <<<"+resourceDir + "/" + fileName +">>> reading failed.");
                value = "Error occured.";
            } catch (MissingResourceException e) {
                // TODO: handle exception
                System.out.println("property not found");
                log.error("Property <<<"+e.getKey()+">>> for <<<"+e.getClassName()+">>> not found.");
                value = "Error occured.";
            }
            return value;
        }

        public static String getErrorMessage(String errorCode) {
            Properties prop = null;
            String message = "";
            String fileName = "errormessage.properties";

            try {
                prop = loadProperties(resourceDir + "/" + fileName);
                message = prop.getProperty(errorCode);
                if (message == null) {
                    throw new MissingResourceException("Property not found.", "ERROR", errorCode)
                }
            } catch (FileNotFoundException e) 
                // TODO Auto-generated catch block
                log.error("Properties file <<<"+resourceDir + "/" + fileName +">>> not found.")
                message = "Something went wrong.";
            } catch (IOException e) {
                // TODO Auto-generated catch bloc
                log.error("Properties file <<<"+resourceDir + "/" + fileName +">>> reading failed.");
                message = "Something went wrong.";
            } catch (MissingResourceException e) {
                // TODO: handle exception
                log.error("Property <<<"+e.getKey()+">>> for <<<"+e.getClassName()+">>> not found.");
                message = "Something went wrong.";
            }
            return message
        }
    }

以下代码在通过网络服务器执行时给出了错误。

    Class.forName(PropertyUtil.getDBPropertyValue("driver"));
    con =  DriverManager.getConnection(PropertyUtil.getDBPropertyValue("url"), 
    PropertyUtil.getDBPropertyValue("username"), 
    PropertyUtil.getDBPropertyValue("password"));
    return con;

这是项目结构。

Answer 1

How to find the working folder of a servlet based application in order to load resources

查看此线程而不是:

InputStream fileStream = new FileInputStream(new File(fileName));

尝试:

InputStream fileStream = getServletContext().getResourceAsStream(fileName);