java - 在不同的类中调用函数时找不到文件异常

Question

我在类中有一个函数来读取配置文件。当我单独运行它时，它会输出(使用 println)我从所述文件中需要的值。但是，当我在另一个类中调用它以使用这些值作为数据库连接的参数时，我收到文件未找到异常。

如果我设置系统中的绝对文件路径(即 D:/File/HereIsTheFile/config.properties)，我可以让它工作，但如果我打包并部署它，那么它就完全没用了。

这是配置读取器:

public class RetConfig {
    public static String retConfig(String param) {
        Properties prop = new Properties();
        try  (InputStream input = new FileInputStream("resources/config.properties")) {
            prop.load(input);
            System.out.println(prop.getProperty("url"));
            System.out.println(prop.getProperty("user"));
            System.out.println(prop.getProperty("password"));
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        return prop.getProperty(param);
    }

    public static void main(String[] args) {
        System.out.println(retConfig("url"));
    }
}

这是另一个类中的函数:

public static List<MyDataType> retSalesShipOem(String queryInput) throws SQLException {
    List<MyDataType> dataList = new  ArrayList<>();
    try (Connection conn = (Connection) DriverManager.getConnection(RetConfig.retConfig("url"), 
                                                                    RetConfig.retConfig("user"),
                                                                    RetConfig.retConfig("password"))) {
        try (Statement stmt = (Statement) conn.createStatement()) {
            try (CachedRowSet crs = RowSetProvider.newFactory().createCachedRowSet(); ) {
                crs.setCommand(queryInput);
                crs.execute(conn);
                conn.setAutoCommit(false);
                while(crs.next()){
                    /*
                     *
                     */
                }
            }
        }
    } catch (Exception e) {
        e.printStackTrace(System.out);
    }       
    return dataList;
}

这是堆栈跟踪(多个错误，但都很相似)

java.io.FileNotFoundException: resources\config.properties (The system cannot find the path specified)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(Unknown Source)
    at java.io.FileInputStream.<init>(Unknown Source)
    at java.io.FileInputStream.<init>(Unknown Source)
    at kpiDBAccess.RetConfig.retConfig(RetConfig.java:15)
    at kpiDBAccess.EnterD.retSalesShipCyo(EnterD.java:81)
    at javascriptChartData.JSDCSales1C.formatChartDataCYO(JSDCSales1C.java:48)
    at javascriptChartData.JSDCSales1C.doGet(JSDCSales1C.java:216)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

Answer 1

我已经重组了类和方法来进行快速测试，我能够很好地读取 resources/config.properties 条目。

资源/config.properties

url:www.google.com
user:bob
password:xxx

读取文件:

public class RetConfig {     
    String urlValue;
    String userValue;
    String pwdValue;

    public void retConfig( ) {
        Properties prop = new Properties();
        try  (InputStream input = new FileInputStream("resources/config.properties")) {
            prop.load(input);
            this.urlValue = prop.getProperty("url");
            this.userValue = prop.getProperty("user");
            this.pwdValue = prop.getProperty("password");
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

调用 #1 类来访问属性。

public class CallRetConfig {
    public static void callerMethod(){
        RetConfig retConfig = new RetConfig();
        retConfig.retConfig();
        System.out.println(" print in second class : "+retConfig.urlValue);
    }   
    public static void main(String[] args) {
        callerMethod();
    }
}

输出:

 print in second class : www.google.com