在不同類中調用函數時發現文件異常

Question

我在類中有一個函數來讀取配置文件。當我自己運行它時，它會輸出（使用println）我需要的文件中的值。但是，當我在另一個類中使用這些值作爲數據庫連接的參數時，我得到一個未找到文件異常。

如果我從我的系統（即D：/File/HereIsTheFile/config.properties）設置絕對文件路徑，但如果我打包並部署，則完全無用。

下面是配置讀取器：

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")); 
    } 
} 

這裏是另一個類的功能：

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; 
} 

這裏是堆棧跟蹤（多錯誤，但所有類似）

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

我已經重組了類和方法來做快速測試，我可以閱讀resources/config.properties條目很好。

資源/ config.properties

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

讀取文件：

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(); 
     } 
    } 
} 

調用＃1類來訪問屬性。

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(); 
    } 
} 

輸出：

print in second class : www.google.com