public class NIODemo {
//TODO 文件锁定时数据需提前备份
    public static void main(String[] args) throws Exception {
        File file = new File("F:"+ File.separator+"vm_realpath"+File.separator+"vm.log");
        FileOutputStream outputStream = new FileOutputStream(file);
        FileChannel channel = outputStream.getChannel();//获取文件输入的Channel
        FileLock fileLock = channel.tryLock();//尝试获取文件锁
        if(fileLock != null){//已经获取了文件锁
            System.out.println("已经获取了文件锁，当前文件被锁定");
            TimeUnit.SECONDS.sleep(10);//锁10秒
            fileLock.release();//解锁
        }
        channel.close();
        outputStream.close();
    }
}

字符集

public class NIODemo {
    public static void main(String[] args) throws Exception {
        SortedMap<String,Charset> map  = Charset.availableCharsets() ;
        for(Map.Entry<String,Charset> entry:map.entrySet()){
            //查看支持的编码
            System.out.println(entry.getKey() + "-"+entry.getValue());
        }
    }
}

编码与解码

public class NIODemo {
    public static void main(String[] args) throws Exception {
        Charset charset = Charset.forName("UTF-8") ;//创建一个“UTF-s"的编码器
        CharsetEncoder encoder= charset.newEncoder() ; //获取编码器
        CharsetDecoder decoder= charset.newDecoder() ; //获取解码器
        CharBuffer buffer = CharBuffer.allocate(20);//分配空间数据
        buffer.put("万邦皆下品，惟有读书高");
        buffer.flip();//重置缓冲区
        ByteBuffer encodeBuffer = encoder.encode(buffer) ;//对缓冲区中的数据进行编码
        System.out.println(decoder.decode(encodeBuffer));
    }
}