[webMethods] 如何從 Java Service 中讀取 Property File

在 Java Service 中，有些設定值我希望不要 hard code 在程式中，要搬到 property file 供日後的設定之用，該如何從 Java Service 中讀取 Property File

property file 檔名為 opc_config.properties ，內容如下:

opc.url=opc.tcp://192.168.1.1:49320
opc.retry.interval=5
opc.max.retries=5
opc.sleep.ms=5000

我目前的開發的目錄是在 Acme 的 package之下:


property file 就要放在 [IntegrationServer 安裝目錄]\instances\default\packages\Acme\resources 之下

值得注意的是，當我們在 load 此 property file 時，路徑規範是 packages\\[你的 package name]\\resources\\[你的 property file name]，如 packages\\Acme\\resources\\opc_config.properties ，若沒按照此規範會出現 FileNotFoundException

Sample code 如下:

    /** 
     * The primary method for the Java service
     *
     * @param pipeline
     *            The IData pipeline
     * @throws ServiceException
     */
    public static final void PropertyFileUtils(IData pipeline) throws ServiceException {
        String config_file = "packages\\Acme\\resources\\opc_config.properties";
        
        try {
            Properties properties = loadProperties(config_file);
            
            String opcUrl = properties.getProperty("opc.url");
            String retryInterval = properties.getProperty("opc.retry.interval");
            String maxRetry = properties.getProperty("opc.max.retries");
            String sleepMs = properties.getProperty("opc.sleep.ms");
            
            logger("opcUrl = " + opcUrl);
            logger("retryInterval = " + retryInterval);
            logger("maxRetry = " + maxRetry);
            logger("sleepMs = " + sleepMs);
            
        } catch (IOException e) {
            throw new ServiceException(e);
        }
    }
    
    // --- <<IS-BEGIN-SHARED-SOURCE-AREA>> ---
    
    public static Properties loadProperties(String config_file) throws ServiceException, IOException{
        Properties properties = new Properties();
        InputStream inputStream = null;
        try {
            inputStream = new FileInputStream(config_file);
            properties.load(inputStream);
        } catch (IOException e) {
            throw new ServiceException(e);
        } finally {
            if (inputStream != null) {
                inputStream.close();
            }
        }
        return properties;
    } 
    
    public static void logger(String message) throws ServiceException {
        IData input = IDataFactory.create();
        
        IDataCursor inputCursor = input.getCursor();
        IDataUtil.put(inputCursor, "message", message);
        IDataUtil.put(inputCursor, "function", "customLogger");
        IDataUtil.put(inputCursor, "level", "INFO");
        inputCursor.destroy();
    
        try {
            Service.doInvoke("pub.flow", "debugLog", input);
        } catch (Exception e) {
            throw new ServiceException(e);
        }
    }
    
    // --- <<IS-END-SHARED-SOURCE-AREA>> ---

相同的，如果你有一些設定用的檔案如 csv 等，也可以放在 resources 目錄下，透過相同的方式皆可讀取得到

Reference
[1] https://goo.gl/EFbLkg