uuid

Android 蓝牙开发（1）

由 ぐ巨炮叔叔 提交于 2019-12-31 19:14:34
普通蓝牙设备官方文档 Android 平台包含蓝牙网络堆栈支持 ，凭借此支持，设备能以无线方式与其他蓝牙设备交换数据。应用框架提供了通过 Android Bluetooth API 访问蓝牙功能的途径。使用 Bluetooth API Android 应用可以执行下面的操作： 扫描其他蓝牙设备 查询本地蓝牙适配器的配对蓝牙设备 建立 RFCOMM 通道 通过服务发现连接到其他设备 与其他设备进行双向数据传输 管理多个连接 传统蓝牙适用于电池使用强度较大的操作，例如 Android 设备之间的流传输和通信等。针对具有低功耗要求的蓝牙设备，Android 4.3（API 18）中引入了面向低功耗蓝牙的 API 支持。 基础知识 使用 Android Bluetooth API 来完成使用蓝牙进行通信的四项主要任务： 设置蓝牙 、 查找局部区域内的配对设备 或可用设备、 连接设备 ，以及在 设备之间传输数据 。 关于蓝牙的 API 在 android.bluetooth 包中，下面介绍一下和蓝牙相关的主要类 BluetoothAdapter 本地蓝牙适配器，是所有 蓝牙交互的入口点 ，表示蓝牙设备自身的一个蓝牙设备适配器， 整个系统只有一个蓝牙适配器 。通过它可以发现其他蓝牙设备，查询绑定（配对）设备的列表，使用已知的 Mac 地址实例化 BluetoothDevice 以及创建

badly formed hexadecimal UUID error string for a UUID primary key

由 允我心安 提交于 2019-12-31 05:37:06
问题 I'm trying to get my table to load, but am getting this error, most likely because my primary key is a uuid. Here is my url paths. path('results/', views.results, name='results'), path('results/<uuid:pk>/', views.genre_book, name='books_genre_table'), Here is my views.py If there is one observation, we load the price table. If not, then we load a table with service descriptions. The user can then pick the service they are most interested and click through to the price table for that service.

fetchUuidWithSdp always giving the cached UUID

由 余生长醉 提交于 2019-12-31 03:03:09
问题 i am writing an app in which i have to do a service discovery on a selected device, but whenever i am doing a fetchUuid it is always giving me the cached UUIDs on the remote device. here is what i am trying public boolean UUIDsearch(BluetoothDevice device){ t=device.fetchUuidsWithSdp(); Log.d(TAG,"Device class = :"+device.getClass()); mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context arg0, Intent intent) { String action = intent.getAction(); //BluetoothDevice

fetchUuidWithSdp always giving the cached UUID

由 戏子无情 提交于 2019-12-31 03:03:06
问题 i am writing an app in which i have to do a service discovery on a selected device, but whenever i am doing a fetchUuid it is always giving me the cached UUIDs on the remote device. here is what i am trying public boolean UUIDsearch(BluetoothDevice device){ t=device.fetchUuidsWithSdp(); Log.d(TAG,"Device class = :"+device.getClass()); mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context arg0, Intent intent) { String action = intent.getAction(); //BluetoothDevice

Why is the 17th digit of version 4 GUIDs limited to only 4 possibilities?

由 巧了我就是萌 提交于 2019-12-30 18:56:07
问题 I understand that this doesn't take a significant chunk off of the entropy involved, and that even if a whole nother character of the GUID was reserved (for any purpose), we still would have more than enough for every insect to have one, so I'm not worried, just curious. As this great answer shows, the Version 4 algorithm for generating GUIDs has the following format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx x is random 4 is constant, this represents the version number. y is one of: 8, 9, A, or B

java生成UUID通用唯一识别码 (Universally Unique Identifier)

由 南笙酒味 提交于 2019-12-30 12:04:40
UUID含义是通用唯一识别码 (Universally Unique Identifier)，这 是一个软件建构的标准，也是被开源软件基金会 (Open Software Foundation, OSF) 的组织在分布式计算环境 (Distributed Computing Environment, DCE) 领域的一部份。UUID 的目的，是让分布式系统中的所有元素，都能有唯一的辨识资讯，而不需要透过中央控制端来做辨识资讯的指定。如此一来，每个人都可以建立不与其它人冲突的 UUID。在这样的情况下，就不需考虑数据库建立时的名称重复问题。目前最广泛应用的 UUID，即是微软的 Microsoft's Globally Unique Identifiers (GUIDs)，而其他重要的应用，则有 Linux ext2/ext3 档案系统、LUKS 加密分割区、GNOME、KDE、Mac OS X 等等。 以下是具体生成UUID的例子： [java] view plain copy package test; import java.util.UUID; public class UUIDGenerator { public UUIDGenerator() { } public static String getUUID() { UUID uuid = UUID.randomUUID(

Git repository unique id

由 ℡╲_俬逩灬. 提交于 2019-12-30 09:00:12
问题 I need to find out if a commit belongs to a particular git repository. The idea is to generate some unique id for every repository I need to test. Then I can compare this unique id to the id, calculated from tested commit. For example take an SHA of initial change set. Can it uniqely identify the repository? 回答1: The SHA1 key is about identifying the content (of a blob, or of a tree), not about a repository. If the content differ from repo to repo, then its history has no common ancestor, so

Git repository unique id

由 我的未来我决定 提交于 2019-12-30 09:00:11
问题 I need to find out if a commit belongs to a particular git repository. The idea is to generate some unique id for every repository I need to test. Then I can compare this unique id to the id, calculated from tested commit. For example take an SHA of initial change set. Can it uniqely identify the repository? 回答1: The SHA1 key is about identifying the content (of a blob, or of a tree), not about a repository. If the content differ from repo to repo, then its history has no common ancestor, so

Generating a short UUID string using uuidtools In Rails

由 你。 提交于 2019-12-30 01:51:07
问题 I have to generate a unique and random string which is to be stored in database. For doing this I have used the "uuidtools" gem. Then in my controller I have added the following line: require "uuidtools" and then in my controllers create method I have declared a 'temp' variable and generating a unique and random 'uuid' string like this: temp=UUIDTools::UUID.random_create which is creating a string like this one: f58b1019-77b0-4d44-a389-b402bb3e6d50 Now my problem is I have to make it short,

webSocket客服在线交谈

由 主宰稳场 提交于 2019-12-29 16:03:56
一》用户端 <%@ page language="java" pageEncoding="UTF-8" %> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%> <!DOCTYPE html > <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>客户端</title> <link rel="stylesheet" type="text/css" href="${BasePath }/css/web/chatClt.css" /> <script type="text/javascript" src="${BasePath }/js/jquery-3.2.0.min.js"></script> <script type="text/javascript" src="${BasePath }/js/web/chatClt.js"></script> </head> <body class="keBody"> <div class="kePublic"> <!-
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