JAVA常用IO操作（转）
package com.syj.util; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.io.PrintWriter; import java.io.StringReader; import java.util.Arrays; /** * <p> * Title:IO工具类 * </p> * * <p> * Description:常用的IO操作封装 * </p> * * <p> * Copyright: 转载请注明出处http://blog.csdn.net/sunyujia/ * </p> * * @author 孙钰佳 * @main sunyujia@yahoo.cn * @date Jun 15, 2008 4:37:58 PM */ public class IOUtil { /** * 缓冲区大小 1MB */ private static final int BUFFER_SIZE = 1024 * 1024; /** * * Description: 将输入流输出到输出流 * * @param in * 输入流 * @param out * 输出流 * @param bufferSize * 缓冲区大小 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 5:57:24 PM */ public static void in2OutStream(InputStream in, OutputStream out, int bufferSize) throws IOException { byte[] buffer = new byte;// 缓冲区 for (int bytesRead = 0; (bytesRead = in.read(buffer)) != -1;) { out.write(buffer, 0, bytesRead); Arrays.fill(buffer, (byte) 0); } } /** * * Description: 读取文件返回字节数组流 * * @param file * 文件 * @return 字节数组流 * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 4:52:41 PM */ public static ByteArrayOutputStream readFileToByteStream(File file) throws IOException { FileInputStream fis = null; ByteArrayOutputStream bos = null; try { fis = new FileInputStream(file); bos = new ByteArrayOutputStream(); in2OutStream(fis, bos, BUFFER_SIZE); } finally { if (fis != null) fis.close(); } return bos; } /** * * Description:读取文件返回字节数组 * * @param file * 文件 * @return 字节数组 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 5:38:50 PM */ public static byte[] readFileToByteArray(File file) throws IOException { ByteArrayOutputStream bos = null; try { bos = readFileToByteStream(file); } finally { if (bos != null) bos.close(); } return bos.toByteArray(); } /** * * Description:读取文件内容 * * @param file * 文件 * @return String内容 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 5:46:32 PM */ public static String readFileToString(File file) throws IOException { StringBuffer sb = null; BufferedReader in = null; try { in = new BufferedReader(new FileReader(file)); sb = new StringBuffer(); for (String line; (line = in.readLine()) != null;) { sb.append(line + "\r\n"); } } finally { if (in != null) in.close(); } return sb.toString(); } /** * * Description:复制文件 * * @param src * 源文件 * @param dest * 目标文件 * @param cover * 是否覆盖 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 6:08:28 PM */ public static void copyFile(File src, File dest, boolean cover) throws IOException { FileInputStream in = null; FileOutputStream out = null; try { if (!dest.exists()) { dest.createNewFile(); } else if (dest.exists() && cover) { dest.delete(); dest.createNewFile(); } else { return; } in = new FileInputStream(src); out = new FileOutputStream(dest); in2OutStream(in, out, BUFFER_SIZE); } finally { try { if (in != null) in.close(); } finally { if (out != null) out.close(); } } } /** * * Description:写文件 * * @param file * 文件 * @param str * 内容 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 6:17:24 PM */ public static void writeFile(File file, String str) throws IOException { PrintWriter out = null; BufferedReader in = null; try { if (!file.exists()) file.createNewFile(); in = new BufferedReader(new StringReader(str)); out = new PrintWriter(new BufferedWriter(new FileWriter(file))); for (String line; (line = in.readLine()) != null;) { out.println(line); } } finally { try { if (in != null) in.close(); } finally { if (out != null) out.close(); } } } /** * * Description:从控制台读取一串字符串 * * @return 读取的字符串 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 6:42:29 PM */ public static String readStringFromSystemIn() throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); try { return br.readLine(); } finally { if (br != null) br.close(); } } /** * * Description:当ObjectInputStream对象调用 * readObject();时,会从ByteArrayInputStream流中反序列化出的对象 * * * @param bi * @return * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 7:07:53 PM */ public static ObjectInputStream buildObjectInputStream( ByteArrayInputStream bi) throws IOException { return new ObjectInputStream(bi); } /** * * Description:当ObjectOutputStream对象调用 * writeObject(o);时,o对象会序列化到ByteArrayOutputStream流中去 * * @param bos * 字节数组流 * @return 对象输出流 * @throws IOException * @mail sunyujia@yahoo.cn * @since：Jun 15, 2008 7:06:00 PM */ public static ObjectOutputStream buildObjectOutputStream( ByteArrayOutputStream bos) throws IOException { return new ObjectOutputStream(bos); } public static BufferedReader buildBufferedReader(String str) { return new BufferedReader(new StringReader(str)); } public static ByteArrayInputStream buildByteArrayInputStream(String str) { return new ByteArrayInputStream(str.getBytes()); } public static ByteArrayInputStream buildByteArrayInputStream(byte[] bt) { return new ByteArrayInputStream(bt); } public static void main(String[] args) throws Exception { byte[] bootFileBytes = IOUtil.readFileToByteArray(new File( "C:\\boot.ini")); System.out.println(new String(bootFileBytes)); String bootFileStr = readFileToString(new File("C:\\boot.ini")); System.out.println(bootFileStr); System.out.println(new String(bootFileBytes).equals(bootFileStr)); IOUtil.copyFile(new File("C:\\boot.ini"), new File("C:\\boot1.ini"), true); IOUtil.writeFile(new File("C:\\boot2.ini"), bootFileStr); ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = IOUtil.buildObjectOutputStream(bos); oos.writeObject(new String("abcd")); ObjectInputStream ois = IOUtil.buildObjectInputStream(IOUtil .buildByteArrayInputStream(bos.toByteArray())); System.out.println(ois.readObject()); System.out.println(IOUtil.readStringFromSystemIn()); } }
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