java输入输出IO流

字节流FileInputStream和FileOutputStream复制文件

public static void main(String[] args) throws IOException {
    FileInputStream inputStream = new FileInputStream("d:/abc.jpg");
    FileOutputStream outputStream = new FileOutputStream("e:/abc.jpg");
    byte[] buff = new byte[1024];
    int len = 0;
    while ((len = inputStream.read(buff)) != -1) {
        outputStream.write(buff,0, len);
    }
    inputStream.close();
    outputStream.close();
}

字节缓冲流BufferedInputStream和BufferedOutputStream复制文件

public static void main(String[] args) throws IOException {
    BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream("d:/abc.jpg"));
    BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream("e:/abc.jpg"));
    byte[] buff = new byte[1024];
    int len = 0;
    while ((len = inputStream.read(buff)) != -1) {
        outputStream.write(buff,0, len);
    }
    inputStream.close();
    outputStream.close();
}

字符流FileReader和FileWriter复制文件-会有乱码问题，要保证编码一致

public static void main(String[] args) throws IOException {
    FileReader fileReader = new FileReader("d:/abc.txt");
    FileWriter fileWriter = new FileWriter("D:/def.txt");
    int ch ;
    while ((ch = fileReader.read()) != -1) {
        fileWriter.write(ch);
    }
    fileReader.close();
    fileWriter.close();
}

字符字节转换流OutputStreamWriter和InputStreamReader复制文件

public static void main(String[] args) throws IOException {
    InputStreamReader inputStreamReader = new InputStreamReader(new FileInputStream("D:/gh.txt"), "utf-8");
    OutputStreamWriter outputStreamWriter = new OutputStreamWriter(new FileOutputStream("D:/def.txt"), "utf-8");

    int temp ;
    while ((temp = inputStreamReader.read()) != -1) {
        System.out.println((char)temp);
        outputStreamWriter.write(temp);
    }
    outputStreamWriter.close();
    inputStreamReader.close();
}

缓冲字符流BufferedWriter和BufferedReader复制文件

public static void main(String[] args) throws IOException {
    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(new FileInputStream("D:/gh.txt"), "utf-8"));
    BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("D:/def.txt"), "utf-8"));

    String temp ;
    while ((temp = bufferedReader.readLine()) != null) {
        bufferedWriter.write(temp);
        bufferedWriter.newLine();
    }
    bufferedReader.close();
    bufferedWriter.close();
}

工具类common-io

递归复制文件夹

public static void main(String[] args) throws Exception {
    copyDir(new File("d:/abc"), new File("d:/def"));
}
private static void copyDir(File srcFile, File destFile) throws Exception {
    File[] listFiles = srcFile.listFiles();
    for(File file : listFiles) {
        if (file.isFile()) {
            copyFile(file, new File(destFile,file.getName()));
        }
        if (file.isDirectory()) {
            File toFile = new File(destFile, file.getName());
            toFile.mkdirs();
            copyDir(file, toFile);
        }
    }
}
private static void copyFile(File srcFile, File destFile) throws Exception {
    BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(srcFile));
    BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(destFile));

    byte[] buff = new byte[2048];
    int len ;
    while ((len = bufferedInputStream.read(buff)) != -1) {
        bufferedOutputStream.write(buff,0,len);
        bufferedOutputStream.flush();
    }
    bufferedInputStream.close();
    bufferedOutputStream.close();
}