Here you can find the source of readFile(File file)
public static String readFile(File file) throws IOException
//package com.java2s; /**/* w w w . j a v a2 s .c o m*/ * Copyright (c) 2014-2015, biezhi ?? (biezhi.me@gmail.com) * * 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.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.Reader; import java.io.StringWriter; import java.io.UnsupportedEncodingException; import java.io.Writer; public class Main { public static final int BUFFER_SIZE = 4096; public static String readFile(File file) throws IOException { Reader in = new FileReader(file); StringWriter out = new StringWriter(); copy(in, out); return out.toString(); } public static String readFile(File file, String encoding) throws IOException { InputStream inputStream = new FileInputStream(file); return toString(encoding, inputStream); } public static int copy(File in, File out) throws IOException { return copy(new BufferedInputStream(new FileInputStream(in)), new BufferedOutputStream(new FileOutputStream(out))); } public static void copy(byte[] in, File out) throws IOException { ByteArrayInputStream inStream = new ByteArrayInputStream(in); OutputStream outStream = new BufferedOutputStream(new FileOutputStream(out)); copy(inStream, outStream); } public static int copy(InputStream in, OutputStream out) throws IOException { try { int byteCount = 0; byte[] buffer = new byte[BUFFER_SIZE]; int bytesRead = -1; while ((bytesRead = in.read(buffer)) != -1) { out.write(buffer, 0, bytesRead); byteCount += bytesRead; } out.flush(); return byteCount; } finally { try { in.close(); } catch (IOException ex) { } try { out.close(); } catch (IOException ex) { } } } public static void copy(byte[] in, OutputStream out) throws IOException { try { out.write(in); } finally { try { out.close(); } catch (IOException ex) { } } } public static int copy(Reader in, Writer out) throws IOException { try { int byteCount = 0; char[] buffer = new char[BUFFER_SIZE]; int bytesRead = -1; while ((bytesRead = in.read(buffer)) != -1) { out.write(buffer, 0, bytesRead); byteCount += bytesRead; } out.flush(); return byteCount; } finally { try { in.close(); } catch (IOException ex) { } try { out.close(); } catch (IOException ex) { } } } public static void copy(String in, Writer out) throws IOException { try { out.write(in); } finally { try { out.close(); } catch (IOException ex) { } } } public static String toString(InputStream inputStream) throws UnsupportedEncodingException, IOException { Reader reader = new InputStreamReader(inputStream); StringWriter writer = new StringWriter(); copy(reader, writer); return writer.toString(); } public static String toString(String encoding, InputStream inputStream) throws UnsupportedEncodingException, IOException { Reader reader = new InputStreamReader(inputStream, encoding); StringWriter writer = new StringWriter(); copy(reader, writer); return writer.toString(); } }