Java tutorial
/* * Copyright 2010 Proofpoint, Inc. * * Licensed 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 com.proofpoint.configuration; import com.google.common.collect.ImmutableMap; import com.google.common.collect.ImmutableSortedMap; import com.google.common.collect.Maps; import java.io.File; import java.io.FileReader; import java.io.IOException; import java.io.Reader; import java.util.Map; import java.util.Properties; public class ConfigurationLoader { public Map<String, String> loadProperties() throws IOException { Map<String, String> result = Maps.newTreeMap(); String configFile = System.getProperty("config"); if (configFile != null) { result.putAll(loadPropertiesFrom(configFile)); } result.putAll(getSystemProperties()); return ImmutableSortedMap.copyOf(result); } /** * Loads properties from the given file * * @param path file path * @return properties * @throws IOException errors */ public Map<String, String> loadPropertiesFrom(String path) throws IOException { Reader reader = new FileReader(new File(path)); Properties properties = new Properties(); try { properties.load(reader); } finally { reader.close(); } return toMap(properties); } public Map<String, String> getSystemProperties() { return toMap(System.getProperties()); } private static ImmutableMap<String, String> toMap(Properties properties) { ImmutableMap.Builder<String, String> result = ImmutableMap.builder(); for (Map.Entry<Object, Object> entry : properties.entrySet()) { result.put(entry.getKey().toString(), entry.getValue().toString()); } return result.build(); } }