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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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 com.alibaba.jstorm.utils; import backtype.storm.utils.Utils; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.Writer; import java.net.URL; import java.util.ArrayList; import java.util.Enumeration; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Properties; import org.apache.commons.io.FileUtils; import org.apache.commons.lang.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.yaml.snakeyaml.Yaml; import org.yaml.snakeyaml.constructor.SafeConstructor; public class LoadConf { private static final Logger LOG = LoggerFactory.getLogger(LoadConf.class); public static List<URL> findResources(String name) { try { Enumeration<URL> resources = Thread.currentThread().getContextClassLoader().getResources(name); List<URL> ret = new ArrayList<>(); while (resources.hasMoreElements()) { ret.add(resources.nextElement()); } return ret; } catch (IOException e) { throw new RuntimeException(e); } } /** * @param name conf file name * @param mustExist if true, the file must exist, otherwise throw an exception * @param canMultiple if false and there is multiple conf, it will throw an exception * @return conf map */ public static Map findAndReadYaml(String name, boolean mustExist, boolean canMultiple) { InputStream in = null; boolean confFileEmpty = false; try { in = getConfigFileInputStream(name, canMultiple); if (null != in) { Yaml yaml = new Yaml(new SafeConstructor()); Map ret = (Map) yaml.load(new InputStreamReader(in)); if (null != ret) { return new HashMap(ret); } else { confFileEmpty = true; } } if (mustExist) { if (confFileEmpty) throw new RuntimeException("Config file " + name + " doesn't have any valid storm configs"); else throw new RuntimeException("Could not find config file on classpath " + name); } else { return new HashMap(); } } catch (IOException e) { StringBuilder sb = new StringBuilder(); sb.append("Invalid configuration ").append(name).append(":").append(e.getMessage()); throw new RuntimeException(sb.toString(), e); } finally { if (null != in) { try { in.close(); } catch (IOException e) { throw new RuntimeException(e); } } } } public static InputStream getConfigFileInputStream(String configFilePath, boolean canMultiple) throws IOException { if (null == configFilePath) { throw new IOException("Could not find config file, name not specified"); } HashSet<URL> resources = new HashSet<>(findResources(configFilePath)); if (resources.isEmpty()) { File configFile = new File(configFilePath); if (configFile.exists()) { return new FileInputStream(configFile); } } else if (resources.size() > 1 && !canMultiple) { throw new IOException("Found multiple " + configFilePath + " resources. " + "You're probably bundling storm jars with your topology jar. " + resources); } else { LOG.debug("Using " + configFilePath + " from resources"); URL resource = resources.iterator().next(); return resource.openStream(); } return null; } public static InputStream getConfigFileInputStream(String configFilePath) throws IOException { return getConfigFileInputStream(configFilePath, true); } public static Map LoadYaml(String confPath) { return findAndReadYaml(confPath, true, true); } public static Map LoadProperty(String prop) { InputStream in = null; Properties properties = new Properties(); try { in = getConfigFileInputStream(prop); properties.load(in); } catch (FileNotFoundException e) { throw new RuntimeException("No such file " + prop); } catch (Exception e1) { throw new RuntimeException("Failed to read config file"); } finally { if (null != in) { try { in.close(); } catch (IOException e) { throw new RuntimeException(e); } } } Map ret = new HashMap(); ret.putAll(properties); return ret; } public static String getStormYamlPath() { String confFile = System.getProperty("storm.conf.file"); if (!StringUtils.isBlank(confFile)) { return confFile; } else { return new File(System.getProperty("jstorm.home"), "conf/storm.yaml").getAbsolutePath(); } } /** * dumps a conf map into a file, note that the output yaml file uses a compact format * e.g., for a list, it uses key: [xx, xx] instead of multiple lines. */ public static void dumpYaml(Map conf, String file) { Yaml yaml = new Yaml(); try { Writer writer = new OutputStreamWriter(new FileOutputStream(file), "UTF-8"); yaml.dump(conf, writer); } catch (Exception ex) { LOG.error("Error:", ex); } } public static Map loadYamlFromString(String configStr) { if (configStr == null) { return null; } Yaml yaml = new Yaml(); try { return yaml.loadAs(configStr, Map.class); } catch (Exception ex) { LOG.error("Error:", ex); } return null; } public static void backupAndOverwriteStormYaml(String confData) { String path = getStormYamlPath(); LOG.info("backing current storm.yaml..."); for (int i = 2; i > 0; i--) { mv(path + "." + i, path + "." + (i + 1)); } mv(path, path + ".1"); LOG.info("updating storm.yaml at: {}", path); Utils.flushToFile(path, confData, false); } public static void mv(String src, String dest) { try { FileUtils.moveFile(new File(src), new File(dest)); } catch (Exception ignored) { } } }