抽象模型，严谨代码，开源分享

分手后的思念是犯贱 2022-08-23 12:50 174阅读 0赞

前言  
    首先，感谢Eric对我代码上的建议，感谢Stone在FTP Lab环境部署上对我的指导。  
  
    今年4月份的时候，做了一个小的项目，当时也没有去总结整理，现在想想总结整理是很有必要的，这也是一个很好的工作研究的习惯。  
  
    关于项目，不论大小，其实做到极致也不是一件容易的事。只有做到极致，才算真正的项目经验；只有做到极致，才能让编程真正成为一门艺术；只有体会编程是一门有趣的艺术时，你的职业生涯才经久不衰，常青不老。  
  
    当然，我现在也只是一个走在编程艺术道路上的小孩，不停探索，充满好奇，我也希望志同道合的同仁们给我指教与分享。  
  
    我相信，只有开源了，才会有更多更大的进步，才会有活力，有创造力。我支持开源与自由，我唾弃陈旧死板的开发与管理！  
  
  
项目简介  
    略......  
  
编程点滴

1. 同样一个文件能只打开一次搞定的，就只打开一次，避免频繁的I/O流操作。比如：读一个属性文件，文件中有很多属性项目，我们可以将属性项预定义在一个数组里，当打开属性文件时，遍历属性数组，将得到的属性键值对预存在一个哈希表里，这样之后在用到属性值时，只需从哈希表里获取就可以了。

String[] propertyArray = new String[] { "templateDirectory", "sourceDirectory", "cm",  
                "filereadyfile", "xmlCMIRPVersion", "expireHour",  
                "meLimitCount", "fileNamePrefix", "subObjectLimitCount" };  
          
        Map<String, String> propertyMap = CommonTool.getPropertyMap(ConstantPool.CM_CONFIGRATION_FILE, propertyArray);

public static Map<String, String> getPropertyMap(String cmccCmConfigurationFile, String[] propertyArray) {  
            InputStream inputStream = null;  
          
            Map<String, String> propertyMap = new HashMap<String, String>();  
            int propertyArrayLength = propertyArray.length;  
          
            Properties properties = new Properties();  
          
            try {  
                inputStream = Files.newInputStream(Paths.get(cmccCmConfigurationFile));  
                properties.load(inputStream);  
            } catch (IOException ioe) {  
                LOG.error(ioe.getMessage());  
                ioe.printStackTrace();  
            } finally {  
                IOUtils.closeQuietly(inputStream);  
            }  
          
            for (int index = 0; index < propertyArrayLength; index++) {  
                String propertyName = propertyArray[index];  
                String propertyValue = properties.getProperty(propertyName);  
          
                if (StringUtils.trimToEmpty(propertyValue).equals("")) {  
                    throw new NullPointerException("There is no property " + propertyName + " in the configuration file " + cmccCmConfigurationFile);  
                } else {  
                    propertyValue = StringUtils.trim(propertyValue);  
                }  
          
                propertyMap.put(propertyName, propertyValue);  
            }  
          
            return propertyMap;  
        }

2. 我们能计算一次搞定的，就只计算一次，比如：我们会经常遍历数组，往往会让数组长度的计算在循环中计算多次，这是低效的。

int propertyArrayLength = propertyArray.length;  
      
    for (int index = 0; index < propertyArrayLength; index++) {  
        ......  
    }

for (int index = 0; index < propertyArray.length; index++) {  
        ......  
    }

3. 我们处理属性文件时，一定要严谨，比如：有个属性项是表示数量的，当我们获取到该属性项时，我们要对其进行数字正则判断，要不然你得到一个非数字的属性，你怎么拿来运算？

public static boolean isDigit(String str) {  
        boolean isDigitFlag = false;  
      
        if (str.matches("(^[-|+]?)\\d+")) {  
            isDigitFlag = true;  
        }  
      
        return isDigitFlag;  
    }

4. 我们经常会拼凑，传参等方式来定义文件名，所以在这种情况下，有必要对文件名合法性与否作出正则判断。

public static boolean isInvalidFileName(String fileName) {  
        boolean isInvalidFileNameFlag = false;  
      
        if (fileName.matches(".*[\\/:\\*\\?\"<>\\|].*")) {  
            isInvalidFileNameFlag = true;  
        }  
      
        return isInvalidFileNameFlag;  
    }

5. 我们对特殊字符的处理，也要严谨，考虑方方面面，比如：在文件中将'&'转换成'&'，'<'转换成'<'，'>'转换成'>'，在这种情况下，你就不能将'&'和'<'，以及'>'中的'&'再转换成'&'了。

public static String replaceReserveSymbel(String convertPartStr) {  
            if (convertPartStr != null) {  
                if (convertPartStr.contains("&")) {  
                    StringBuffer sb = new StringBuffer("");  
                    convertPartStr = replaceReserveSymbel(convertPartStr, sb);  
                }  
          
                convertPartStr = convertPartStr.replace("<", "<");  
                convertPartStr = convertPartStr.replace(">", ">");  
          
                convertPartStr = convertPartStr.replace("\\", "\\\\");  
                convertPartStr = convertPartStr.replace("{", "\\{");  
                convertPartStr = convertPartStr.replace("}", "\\}");  
                convertPartStr = convertPartStr.replace("(", "\\(");  
                convertPartStr = convertPartStr.replace(")", "\\)");  
                convertPartStr = convertPartStr.replace(",", "\\,");  
            }  
          
            return convertPartStr;  
        }  
          
        public static String replaceReserveSymbel(String convertPartStr, StringBuffer sb) {  
            int index = convertPartStr.indexOf("&");  
          
            String leftStr = "";  
            String rightStr = "";  
          
            if (index >= 0) {  
                leftStr = convertPartStr.substring(0, index + 1);  
                rightStr = convertPartStr.substring(index + 1);  
          
                sb.append(leftStr);  
          
                if (!rightStr.startsWith("amp;") && !rightStr.startsWith("lt;") && !rightStr.startsWith("gt;")) {  
                    sb.append("amp;");  
                }  
          
                replaceReserveSymbel(rightStr, sb);  
            } else {  
                sb.append(convertPartStr);  
            }  
          
            return sb.toString();  
        }

6. 在多线程编程中，我们很多时候要实现接口Callable<?>, 而非实现接口Runnable,接口Callable<?>给我们带来的方便是不言而喻的，因为，可以重写它的方法call()，获得我们想要的返回值。

/** 
         * @author shengshu 
         *  
         */  
        public class ConverterTask implements Callable<File> {  
            private static final Logger LOG = Logger.getLogger(ConverterTask.class);  
          
            private File templateFile = null;  
            private File fragmentFile = null;  
            private String exportDirectoryStr = null;  
            private String notificationDirectoryStr = null;  
          
            public String fileNamePrefix = null;  
          
            private static final Date date = new Date();  
          
            public ConverterTask(File fragmentFile, File templateFile, String destDirectoryStr, String notificationDirectoryStr, String fileNamePrefix) {  
                this.fragmentFile = fragmentFile;  
                this.templateFile = templateFile;  
                this.exportDirectoryStr = destDirectoryStr;  
                this.notificationDirectoryStr = notificationDirectoryStr;  
          
                this.fileNamePrefix = fileNamePrefix;  
            }  
          
            public File convertFile(File fragmentFile, File templateFile, String exportDirectoryStr, String notificationDirectoryStr, String fileNamePrefix) {  
          
                ......  
          
                return exportFile;  
            }  
          
            public void convertFile(File fragmentFile, File templateFile, File exportDirectory, File notificationDirectory, String fileNamePrefix) throws Throwable {  
                convertFile(fragmentFile, templateFile, exportDirectory.getAbsolutePath(), notificationDirectory.getAbsolutePath(), fileNamePrefix);  
            }  
          
            @Override  
            public File call() throws Exception {  
                File exportFile = convertFile(fragmentFile, templateFile, exportDirectoryStr, notificationDirectoryStr, fileNamePrefix);  
          
                return exportFile;  
            }  
          
        }

private static void initConverter() {  
            LOG.info("Converter thread pool size: " + threadPoolSize);  
            converterThreadPool = Executors.newFixedThreadPool(threadPoolSize);  
          
            converterFutureList = new ArrayList<Future<File>>();  
          
            if (sourceDirectory != null && sourceDirectory.isDirectory()) {  
                fragmentFileCollection = FileUtils.listFiles(sourceDirectory, new String[] { "xml", "XML" }, false);  
            } else {  
                LOG.warn("The directory " + sourceDirectoryStr + " doesn't exist or is invalid!");  
            }  
          
            if (templateDirectory != null && templateDirectory.isDirectory()) {  
                templateFileCollection = FileUtils.listFiles(templateDirectory, new String[] { "xsl", "XSL" }, false);  
            } else {  
                LOG.warn("The directory " + templateDirectoryStr + " doesn't exist or is invalid!");  
            }  
        }  
          
        public void converter() {  
            LOG.info("==================Converter Start==================");  
            startTime = System.currentTimeMillis();  
          
            initConverter();  
          
            if ((fragmentFileCollection != null && !fragmentFileCollection.isEmpty()) && (templateFileCollection != null && !templateFileCollection.isEmpty())) {  
          
                Iterator<File> fragmentFileIterator = fragmentFileCollection.iterator();  
          
                while (fragmentFileIterator.hasNext()) {  
                    File fragmentFile = fragmentFileIterator.next();  
                    LOG.info("Fragment file: " + fragmentFile);  
          
                    Iterator<File> templateFileIterator = templateFileCollection.iterator();  
          
                    while (templateFileIterator.hasNext()) {  
                        File templateFile = templateFileIterator.next();  
                        LOG.info("Template file: " + templateFile);  
          
                        ConverterTask converterTask = new ConverterTask(fragmentFile, templateFile, exportDirectoryStr, notificationDirectoryStr, fileNamePrefix);  
          
                        Future<File> converterFuture = converterThreadPool.submit(converterTask);  
          
                        converterFutureList.add(converterFuture);  
                    }  
                }  
            }  
          
            destroyConverter();  
          
            endTime = System.currentTimeMillis();  
            deltaTime = endTime - startTime;  
            LOG.info("Converter spend " + deltaTime / 1000 + " seconds");  
            LOG.info("==================Converter End==================");  
        }  
          
        private static void destroyConverter() {  
            LOG.info("===Start to destroy thread pool and delete files under source directory===");  
          
            for (Future<File> future : converterFutureList) {  
                try {  
                    File exportFile = future.get();  
          
                    if (exportFile.exists()) {  
                        LOG.info("Invoke method call() and return : " + exportFile);  
                        exportFileCollection.add(exportFile);  
                    }  
                } catch (InterruptedException ie) {  
                    ie.printStackTrace();  
                } catch (ExecutionException ee) {  
                    ee.printStackTrace();  
                }  
            }  
          
            converterThreadPool.shutdown();  
            LOG.info("Thread pool is changed as status: SHUTDOWN");  
          
            while (!converterThreadPool.isTerminated())  
                ;  
          
            LOG.info("Thread pool is changed as status: STOP");  
          
            if (!CommonTool.deleteFileCollection(fragmentFileCollection)) {  
                LOG.error("Fail to delete fragment files under directory " + sourceDirectoryStr);  
            }  
          
            LOG.info("===End to destroy thread pool and delete files under source directory===");  
        }

7. 我们会经常处理多线程，高并发的问题，往往会用到线程池，所以我们既要保证任务都能被执行，又能保证线程池正常终止。

subSpliterThreadPool.shutdown();  
      
    while (!subSpliterThreadPool.isTerminated())  
        ;

8. 在处理XML文件时，对XSLT的应用将会大大简化我们的代码逻辑与数量，实现代码与文本处理的解耦。

待续...