Java tutorial
/* * Copyright 2014-2016 CyberVision, 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 org.kaaproject.kaa.server.common.utils; import org.apache.commons.io.IOUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.Properties; public class FileUtils { private static final Logger LOG = LoggerFactory.getLogger(FileUtils.class); private FileUtils() { } /** * Read resource. * * @param resource the resource * @return the string * @throws IOException Signals that an I/O exception has occurred. */ public static String readResource(String resource) throws IOException { String result = null; try { StringBuffer fileData = new StringBuffer(); InputStream input = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource); BufferedReader reader = new BufferedReader(new InputStreamReader(input)); char[] buf = new char[1024]; int numRead = 0; while ((numRead = reader.read(buf)) != -1) { String readData = String.valueOf(buf, 0, numRead); fileData.append(readData); } reader.close(); result = fileData.toString(); } catch (IOException exception) { LOG.error("Unable to read from specified resource '" + resource + "'! Error: " + exception.getMessage(), exception); throw exception; } return result; } /** * Read resource bytes. * * @param resource the resource * @return the byte array * @throws IOException Signals that an I/O exception has occurred. */ public static byte[] readResourceBytes(String resource) throws IOException { try (InputStream input = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource)) { return IOUtils.toByteArray(input); } catch (IOException exception) { LOG.error("Unable to read from specified resource '" + resource + "'! Error: " + exception.getMessage(), exception); throw exception; } } /** * Read resource peroperties. * * @param resource the resource * @return the properties * @throws IOException Signals that an I/O exception has occurred. */ public static Properties readResourceProperties(String resource) throws IOException { Properties result = null; try { InputStream input = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource); result = new Properties(); result.load(input); input.close(); } catch (IOException exception) { LOG.error("Unable to read from specified resource '" + resource + "'! Error: " + exception.getMessage(), exception); throw exception; } return result; } }