知识大全 java 常用IO操作

Posted 2022-07-19 文件

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　　package 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;

/** * * Title:IO工具类 * * * * Description:常用的IO操作封装 * * * * Copyright: 转载请注明出处<A > </A> * * * @author 孙钰佳 * @main <A >mailto: > </A> * @date Jun : : PM */

　　public class IOUtil /** * 缓冲区大小 MB */ private static final int BUFFER_SIZE = * ;

/** * * 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 <A >mailto: > </A> * @since Jun : : PM */ public static void in OutStream(InputStream in OutputStream out

　　package syj util;

/** * * Title:IO工具类 * * * * Description:常用的IO操作封装 * * * * Copyright: 转载请注明出处 * * * @author 孙钰佳 * @main * @date Jun : : PM */

　　public class IOUtil /** * 缓冲区大小 MB */ private static final int BUFFER_SIZE = * ;

　　/** * * 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 * @since Jun : : PM */ public static void in OutStream(InputStream in OutputStream out

int bufferSize) throws IOException byte[] buffer = new byte[bufferSize];// 缓冲区 for (int bytesRead = ; (bytesRead = in read(buffer)) != ;) out write(buffer bytesRead); Arrays fill(buffer (byte) ); view plaincopy to clipboardprint? /** * * Description: 读取文件返回字节数组流 * * @param file * 文件 * @return 字节数组流 * @mail <A >mailto: > </A> * @since Jun : : PM */ public static ByteArrayOutputStream readFileToByteStream(File file) throws IOException

　　FileInputStream fis = null; ByteArrayOutputStream bos = null; try fis = new FileInputStream(file); bos = new ByteArrayOutputStream(); in OutStream(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 <A >mailto: > </A> * @since Jun : : 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 <A >mailto: > </A> * @since Jun : : 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 * 是否覆蓋 * @throws IOException * @mail <A >mailto: > </A> * @since Jun : : PM */ public static void copyFile(File src File dest boolean cover) throws IOException

　　/** * * Description: 读取文件返回字节数组流 * * @param file * 文件 * @return 字节数组流 * @mail * @since Jun : : PM */ public static ByteArrayOutputStream readFileToByteStream(File file) throws IOException

　　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 * @since Jun : : 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 * @since Jun : : PM */ public static String readFileToString(File file) throws IOException

　　return sb toString();

　　/** * * Description:复制文件 * * @param src * 源文件 * @param dest * 目标文件 * @param cover * 是否覆蓋 * @throws IOException * @mail * @since Jun : : PM */ public static void copyFile(File src File dest boolean cover) throws IOException

　　view plaincopy to clipboardprint? 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); in OutStream(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 <A >mailto: > </A> * @since Jun : : 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 <A >mailto: > </A> * @since Jun : : 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 <A >mailto: > </A> * @since Jun : : 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 <A >mailto: > </A> * @since Jun : : 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));

　　pyFile(new File( C:\\\\boot ini ) new File( C:\\\\boot ini ) true);

　　IOUtil writeFile(new File( C:\\\\boot ini ) bootFileStr); ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = IOUtil buildObjectOutputStream(bos); oos writeObject(new String( abcd ));

　　ObjectInputStream ois = IOUtil buildObjectInputStream(IOUtil buildByteArrayInputStream(bos toByteArray()));

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