Java tutorial
//package com.java2s; /* * Copyright (C) 2007 The Android Open Source Project * * 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. */ import java.io.File; import java.io.FileInputStream; import java.io.IOException; public class Main { /** * Reads the named file, translating {@link IOException} to a * {@link RuntimeException} of some sort. * * @param fileName {@code non-null;} name of the file to read * @return {@code non-null;} contents of the file */ public static byte[] readFile(String fileName) { File file = new File(fileName); return readFile(file); } /** * Reads the given file, translating {@link IOException} to a * {@link RuntimeException} of some sort. * * @param file {@code non-null;} the file to read * @return {@code non-null;} contents of the file */ public static byte[] readFile(File file) { if (!file.exists()) { throw new RuntimeException(file + ": file not found"); } if (!file.isFile()) { throw new RuntimeException(file + ": not a file"); } if (!file.canRead()) { throw new RuntimeException(file + ": file not readable"); } long longLength = file.length(); int length = (int) longLength; if (length != longLength) { throw new RuntimeException(file + ": file too long"); } byte[] result = new byte[length]; try { FileInputStream in = new FileInputStream(file); int at = 0; while (length > 0) { int amt = in.read(result, at, length); if (amt == -1) { throw new RuntimeException(file + ": unexpected EOF"); } at += amt; length -= amt; } in.close(); } catch (IOException ex) { throw new RuntimeException(file + ": trouble reading", ex); } return result; } }