Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.nutch.util; import org.apache.commons.codec.digest.DigestUtils; import org.apache.commons.io.FileUtils; import org.apache.commons.lang.StringUtils; import org.apache.hadoop.io.MD5Hash; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.File; import java.io.IOException; import java.lang.invoke.MethodHandles; import java.util.Map; public class DumpFileUtil { private static final Logger LOG = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); private final static String DIR_PATTERN = "%s/%s/%s"; private final static String FILENAME_PATTERN = "%s_%s.%s"; private final static Integer MAX_LENGTH_OF_FILENAME = 32; private final static Integer MAX_LENGTH_OF_EXTENSION = 5; public static String getUrlMD5(String url) { byte[] digest = MD5Hash.digest(url).getDigest(); StringBuffer sb = new StringBuffer(); for (byte b : digest) { sb.append(String.format("%02x", b & 0xff)); } return sb.toString(); } public static String createTwoLevelsDirectory(String basePath, String md5, boolean makeDir) { String firstLevelDirName = new StringBuilder().append(md5.charAt(0)).append(md5.charAt(8)).toString(); String secondLevelDirName = new StringBuilder().append(md5.charAt(16)).append(md5.charAt(24)).toString(); String fullDirPath = String.format(DIR_PATTERN, basePath, firstLevelDirName, secondLevelDirName); if (makeDir) { try { FileUtils.forceMkdir(new File(fullDirPath)); } catch (IOException e) { LOG.error("Failed to create dir: {}", fullDirPath); fullDirPath = null; } } return fullDirPath; } public static String createTwoLevelsDirectory(String basePath, String md5) { return createTwoLevelsDirectory(basePath, md5, true); } public static String createFileName(String md5, String fileBaseName, String fileExtension) { if (fileBaseName.length() > MAX_LENGTH_OF_FILENAME) { LOG.info("File name is too long. Truncated to {} characters.", MAX_LENGTH_OF_FILENAME); fileBaseName = StringUtils.substring(fileBaseName, 0, MAX_LENGTH_OF_FILENAME); } if (fileExtension.length() > MAX_LENGTH_OF_EXTENSION) { LOG.info("File extension is too long. Truncated to {} characters.", MAX_LENGTH_OF_EXTENSION); fileExtension = StringUtils.substring(fileExtension, 0, MAX_LENGTH_OF_EXTENSION); } // Added to prevent FileNotFoundException (Invalid Argument) - in *nix environment fileBaseName = fileBaseName.replaceAll("\\?", ""); fileExtension = fileExtension.replaceAll("\\?", ""); return String.format(FILENAME_PATTERN, md5, fileBaseName, fileExtension); } public static String createFileNameFromUrl(String basePath, String reverseKey, String urlString, String epochScrapeTime, String fileExtension, boolean makeDir) { String fullDirPath = basePath + File.separator + reverseKey + File.separator + DigestUtils.sha1Hex(urlString); if (makeDir) { try { FileUtils.forceMkdir(new File(fullDirPath)); } catch (IOException e) { LOG.error("Failed to create dir: {}", fullDirPath); fullDirPath = null; } } if (fileExtension.length() > MAX_LENGTH_OF_EXTENSION) { LOG.info("File extension is too long. Truncated to {} characters.", MAX_LENGTH_OF_EXTENSION); fileExtension = StringUtils.substring(fileExtension, 0, MAX_LENGTH_OF_EXTENSION); } String outputFullPath = fullDirPath + File.separator + epochScrapeTime + "." + fileExtension; return outputFullPath; } public static String displayFileTypes(Map<String, Integer> typeCounts, Map<String, Integer> filteredCounts) { StringBuilder builder = new StringBuilder(); // print total stats builder.append("\nTOTAL Stats:\n"); builder.append("[\n"); int mimetypeCount = 0; for (String mimeType : typeCounts.keySet()) { builder.append(" {\"mimeType\":\""); builder.append(mimeType); builder.append("\",\"count\":\""); builder.append(typeCounts.get(mimeType)); builder.append("\"}\n"); mimetypeCount += typeCounts.get(mimeType); } builder.append("]\n"); builder.append("Total count: " + mimetypeCount + "\n"); // filtered types stats mimetypeCount = 0; if (!filteredCounts.isEmpty()) { builder.append("\nFILTERED Stats:\n"); builder.append("[\n"); for (String mimeType : filteredCounts.keySet()) { builder.append(" {\"mimeType\":\""); builder.append(mimeType); builder.append("\",\"count\":\""); builder.append(filteredCounts.get(mimeType)); builder.append("\"}\n"); mimetypeCount += filteredCounts.get(mimeType); } builder.append("]\n"); builder.append("Total filtered count: " + mimetypeCount + "\n"); } return builder.toString(); } }