JDK之java.nio.file.Files

源码

public static byte[] readAllBytes(Path path) throws IOException {
	// try-with-resources 资源的自动管理（jdk1.7新特性）
    try (SeekableByteChannel sbc = Files.newByteChannel(path);
         InputStream in = Channels.newInputStream(sbc)) {
        long size = sbc.size();
        if (size > (long)MAX_BUFFER_SIZE)
            throw new OutOfMemoryError("Required array size too large");

        return read(in, (int)size);
    }
}

public static List<String> readAllLines(Path path, Charset cs) throws IOException {
	// try-with-resources 资源的自动管理（jdk1.7新特性）
    try (BufferedReader reader = newBufferedReader(path, cs)) {
        List<String> result = new ArrayList<>();
        // 无限循环
        for (;;) {
            String line = reader.readLine();
            if (line == null)
                break;
            result.add(line);
        }
        return result;
    }
}

public static Path write(Path path, byte[] bytes, OpenOption... options)
    throws IOException
{
    // ensure bytes is not null before opening file
    Objects.requireNonNull(bytes);
	// try-with-resources 资源的自动管理（jdk1.7新特性）
    try (OutputStream out = Files.newOutputStream(path, options)) {
        int len = bytes.length;
        int rem = len;
        while (rem > 0) {
            int n = Math.min(rem, BUFFER_SIZE);
            out.write(bytes, (len-rem), n);
            rem -= n;
        }
    }
    return path;
}