热门标签 | HotTags
当前位置:  开发笔记 > 编程语言 > 正文

java常用工具类UUID、Map工具类

这篇文章主要为大家详细介绍了Java常用工具类,包括UUID工具类、Map工具类,具有一定的参考价值,感兴趣的小伙伴们可以参考一下

本文实例为大家分享了Java常用工具类 的具体代码,供大家参考,具体内容如下

UUID工具类

package com.jarvis.base.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * A class that represents an immutable universally unique identifier (UUID).
 * A UUID represents a 128-bit value.
 * 

*

There exist different variants of these global identifiers. The methods * of this class are for manipulating the Leach-Salz variant, although the * constructors allow the creation of any variant of UUID (described below). *

*

The layout of a variant 2 (Leach-Salz) UUID is as follows: *

* The most significant long consists of the following unsigned fields: *

 * 0xFFFFFFFF00000000 time_low
 * 0x00000000FFFF0000 time_mid
 * 0x000000000000F000 version
 * 0x0000000000000FFF time_hi
 * 
* The least significant long consists of the following unsigned fields: *
 * 0xC000000000000000 variant
 * 0x3FFF000000000000 clock_seq
 * 0x0000FFFFFFFFFFFF node
 * 
*

*

The variant field contains a value which identifies the layout of * the UUID. The bit layout described above is valid only for * a UUID with a variant value of 2, which indicates the * Leach-Salz variant. *

*

The version field holds a value that describes the type of this * UUID. There are four different basic types of UUIDs: time-based, * DCE security, name-based, and randomly generated UUIDs. These types * have a version value of 1, 2, 3 and 4, respectively. *

*

For more information including algorithms used to create UUIDs, * see the Internet-Draft UUIDs and GUIDs * or the standards body definition at * ISO/IEC 11578:1996. * * @version 1.14, 07/12/04 * @since 1.5 */ @Deprecated public final class UUID implements java.io.Serializable { /** * Explicit serialVersionUID for interoperability. */ private static final long serialVersiOnUID= -4856846361193249489L; /* * The most significant 64 bits of this UUID. * * @serial */ private final long mostSigBits; /** * The least significant 64 bits of this UUID. * * @serial */ private final long leastSigBits; /* * The version number associated with this UUID. Computed on demand. */ private transient int version = -1; /* * The variant number associated with this UUID. Computed on demand. */ private transient int variant = -1; /* * The timestamp associated with this UUID. Computed on demand. */ private transient volatile long timestamp = -1; /* * The clock sequence associated with this UUID. Computed on demand. */ private transient int sequence = -1; /* * The node number associated with this UUID. Computed on demand. */ private transient long node = -1; /* * The hashcode of this UUID. Computed on demand. */ private transient int hashCode = -1; /* * The random number generator used by this class to create random * based UUIDs. */ private static volatile SecureRandom numberGenerator = null; // Constructors and Factories /* * Private constructor which uses a byte array to construct the new UUID. */ private UUID(byte[] data) { long msb = 0; long lsb = 0; for (int i = 0; i <8; i++) msb = (msb <<8) | (data[i] & 0xff); for (int i = 8; i <16; i++) lsb = (lsb <<8) | (data[i] & 0xff); this.mostSigBits = msb; this.leastSigBits = lsb; } /** * Constructs a new UUID using the specified data. * mostSigBits is used for the most significant 64 bits * of the UUID and leastSigBits becomes the * least significant 64 bits of the UUID. * * @param mostSigBits * @param leastSigBits */ public UUID(long mostSigBits, long leastSigBits) { this.mostSigBits = mostSigBits; this.leastSigBits = leastSigBits; } /** * Static factory to retrieve a type 4 (pseudo randomly generated) UUID. *

* The UUID is generated using a cryptographically strong * pseudo random number generator. * * @return a randomly generated UUID. */ @SuppressWarnings("unused") public static UUID randomUUID() { SecureRandom ng = numberGenerator; if (ng == null) { numberGenerator = ng = new SecureRandom(); } byte[] randomBytes = new byte[16]; ng.nextBytes(randomBytes); randomBytes[6] &= 0x0f; /* clear version */ randomBytes[6] |= 0x40; /* set to version 4 */ randomBytes[8] &= 0x3f; /* clear variant */ randomBytes[8] |= 0x80; /* set to IETF variant */ UUID result = new UUID(randomBytes); return new UUID(randomBytes); } /** * Static factory to retrieve a type 3 (name based) UUID based on * the specified byte array. * * @param name a byte array to be used to construct a UUID. * @return a UUID generated from the specified array. */ public static UUID nameUUIDFromBytes(byte[] name) { MessageDigest md; try { md = MessageDigest.getInstance("MD5"); } catch (NoSuchAlgorithmException nsae) { throw new InternalError("MD5 not supported"); } byte[] md5Bytes = md.digest(name); md5Bytes[6] &= 0x0f; /* clear version */ md5Bytes[6] |= 0x30; /* set to version 3 */ md5Bytes[8] &= 0x3f; /* clear variant */ md5Bytes[8] |= 0x80; /* set to IETF variant */ return new UUID(md5Bytes); } /** * Creates a UUID from the string standard representation as * described in the {@link #toString} method. * * @param name a string that specifies a UUID. * @return a UUID with the specified value. * @throws IllegalArgumentException if name does not conform to the * string representation as described in {@link #toString}. */ public static UUID fromString(String name) { String[] compOnents= name.split("-"); if (components.length != 5) throw new IllegalArgumentException("Invalid UUID string: " + name); for (int i = 0; i <5; i++) components[i] = "0x" + components[i]; long mostSigBits = Long.decode(components[0]).longValue(); mostSigBits <<= 16; mostSigBits |= Long.decode(components[1]).longValue(); mostSigBits <<= 16; mostSigBits |= Long.decode(components[2]).longValue(); long leastSigBits = Long.decode(components[3]).longValue(); leastSigBits <<= 48; leastSigBits |= Long.decode(components[4]).longValue(); return new UUID(mostSigBits, leastSigBits); } // Field Accessor Methods /** * Returns the least significant 64 bits of this UUID's 128 bit value. * * @return the least significant 64 bits of this UUID's 128 bit value. */ public long getLeastSignificantBits() { return leastSigBits; } /** * Returns the most significant 64 bits of this UUID's 128 bit value. * * @return the most significant 64 bits of this UUID's 128 bit value. */ public long getMostSignificantBits() { return mostSigBits; } /** * The version number associated with this UUID. The version * number describes how this UUID was generated. *

* The version number has the following meaning:

*

    *
  • 1 Time-based UUID *
  • 2 DCE security UUID *
  • 3 Name-based UUID *
  • 4 Randomly generated UUID *
* * @return the version number of this UUID. */ public int version() { if (version <0) { // Version is bits masked by 0x000000000000F000 in MS long version = (int) ((mostSigBits >> 12) & 0x0f); } return version; } /** * The variant number associated with this UUID. The variant * number describes the layout of the UUID. *

* The variant number has the following meaning:

*

    *
  • 0 Reserved for NCS backward compatibility *
  • 2 The Leach-Salz variant (used by this class) *
  • 6 Reserved, Microsoft Corporation backward compatibility *
  • 7 Reserved for future definition *
* * @return the variant number of this UUID. */ public int variant() { if (variant <0) { // This field is composed of a varying number of bits if ((leastSigBits >>> 63) == 0) { variant = 0; } else if ((leastSigBits >>> 62) == 2) { variant = 2; } else { variant = (int) (leastSigBits >>> 61); } } return variant; } /** * The timestamp value associated with this UUID. *

*

The 60 bit timestamp value is constructed from the time_low, * time_mid, and time_hi fields of this UUID. The resulting * timestamp is measured in 100-nanosecond units since midnight, * October 15, 1582 UTC.

*

* The timestamp value is only meaningful in a time-based UUID, which * has version type 1. If this UUID is not a time-based UUID then * this method throws UnsupportedOperationException. * * @throws UnsupportedOperationException if this UUID is not a * version 1 UUID. */ public long timestamp() { if (version() != 1) { throw new UnsupportedOperationException("Not a time-based UUID"); } long result = timestamp; if (result <0) { result = (mostSigBits & 0x0000000000000FFFL) <<48; result |= ((mostSigBits >> 16) & 0xFFFFL) <<32; result |= mostSigBits >>> 32; timestamp = result; } return result; } /** * The clock sequence value associated with this UUID. *

*

The 14 bit clock sequence value is constructed from the clock * sequence field of this UUID. The clock sequence field is used to * guarantee temporal uniqueness in a time-based UUID.

*

* The clockSequence value is only meaningful in a time-based UUID, which * has version type 1. If this UUID is not a time-based UUID then * this method throws UnsupportedOperationException. * * @return the clock sequence of this UUID. * @throws UnsupportedOperationException if this UUID is not a * version 1 UUID. */ public int clockSequence() { if (version() != 1) { throw new UnsupportedOperationException("Not a time-based UUID"); } if (sequence <0) { sequence = (int) ((leastSigBits & 0x3FFF000000000000L) >>> 48); } return sequence; } /** * The node value associated with this UUID. *

*

The 48 bit node value is constructed from the node field of * this UUID. This field is intended to hold the IEEE 802 address * of the machine that generated this UUID to guarantee spatial * uniqueness.

*

* The node value is only meaningful in a time-based UUID, which * has version type 1. If this UUID is not a time-based UUID then * this method throws UnsupportedOperationException. * * @return the node value of this UUID. * @throws UnsupportedOperationException if this UUID is not a * version 1 UUID. */ public long node() { if (version() != 1) { throw new UnsupportedOperationException("Not a time-based UUID"); } if (node <0) { node = leastSigBits & 0x0000FFFFFFFFFFFFL; } return node; } // Object Inherited Methods /** * Returns a String object representing this * UUID. *

*

The UUID string representation is as described by this BNF : *

 * UUID   =  "-"  "-"
 *     "-"
 *     "-"
 *    
 * time_low  = 4*
 * time_mid  = 2*
 * time_high_and_version = 2*
 * variant_and_sequence = 2*
 * node   = 6*
 * hexOctet  = 
 * hexDigit  =
 * "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
 * | "a" | "b" | "c" | "d" | "e" | "f"
 * | "A" | "B" | "C" | "D" | "E" | "F"
 * 
* * @return a string representation of this UUID. */ public String toString() { return (digits(mostSigBits >> 32, 8) + "-" + digits(mostSigBits >> 16, 4) + "-" + digits(mostSigBits, 4) + "-" + digits(leastSigBits >> 48, 4) + "-" + digits(leastSigBits, 12)); } /** * Returns val represented by the specified number of hex digits. */ private static String digits(long val, int digits) { long hi = 1L <<(digits * 4); return Long.toHexString(hi | (val & (hi - 1))).substring(1); } /** * Returns a hash code for this UUID. * * @return a hash code value for this UUID. */ public int hashCode() { if (hashCode == -1) { hashCode = (int) ((mostSigBits >> 32) ^ mostSigBits ^ (leastSigBits >> 32) ^ leastSigBits); } return hashCode; } /** * Compares this object to the specified object. The result is * true if and only if the argument is not * null, is a UUID object, has the same variant, * and contains the same value, bit for bit, as this UUID. * * @param obj the object to compare with. * @return true if the objects are the same; * false otherwise. */ public boolean equals(Object obj) { if (!(obj instanceof UUID)) return false; if (((UUID) obj).variant() != this.variant()) return false; UUID id = (UUID) obj; return (mostSigBits == id.mostSigBits && leastSigBits == id.leastSigBits); } // Comparison Operations /** * Compares this UUID with the specified UUID. *

*

The first of two UUIDs follows the second if the most significant * field in which the UUIDs differ is greater for the first UUID. * * @param val UUID to which this UUID is to be compared. * @return -1, 0 or 1 as this UUID is less than, equal * to, or greater than val. */ public int compareTo(UUID val) { // The ordering is intentionally set up so that the UUIDs // can simply be numerically compared as two numbers return (this.mostSigBits val.mostSigBits &#63; 1 : (this.leastSigBits val.leastSigBits &#63; 1 : 0)))); } /** * Reconstitute the UUID instance from a stream (that is, * deserialize it). This is necessary to set the transient fields * to their correct uninitialized value so they will be recomputed * on demand. */ private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, ClassNotFoundException { in.defaultReadObject(); // Set "cached computation" fields to their initial values version = -1; variant = -1; timestamp = -1; sequence = -1; node = -1; hashCode = -1; } }

Map工具类

package com.jarvis.base.util;

import java.util.Map;
/**
 * 
 * 
 * @Title: MapHelper.java
 * @Package com.jarvis.base.util
 * @Description:Map工具类
 * @version V1.0 
 */
public class MapHelper {
 /**
 * 获得字串值
 *
 * @param name
 *  键值名称
 * @return 若不存在,则返回空字串
 */
 public static String getString(Map<&#63;, &#63;> map, String name) {
 if (name == null || name.equals("")) {
 return "";
 }

 String value = "";
 if (map.containsKey(name) == false) {
 return "";
 }
 Object obj = map.get(name);
 if (obj != null) {
 value = obj.toString();
 }
 obj = null;

 return value;
 }

 /**
 * 返回整型值
 *
 * @param name
 *  键值名称
 * @return 若不存在,或转换失败,则返回0
 */
 public static int getInt(Map<&#63;, &#63;> map, String name) {
 if (name == null || name.equals("")) {
 return 0;
 }

 int value = 0;
 if (map.containsKey(name) == false) {
 return 0;
 }

 Object obj = map.get(name);
 if (obj == null) {
 return 0;
 }

 if (!(obj instanceof Integer)) {
 try {
 value = Integer.parseInt(obj.toString());
 } catch (Exception ex) {
 ex.printStackTrace();
 System.err.println("name[" + name + "]对应的值不是数字,返回0");
 value = 0;
 }
 } else {
 value = ((Integer) obj).intValue();
 obj = null;
 }

 return value;
 }

 /**
 * 获取长整型值
 *
 * @param name
 *  键值名称
 * @return 若不存在,或转换失败,则返回0
 */
 public static long getLong(Map<&#63;, &#63;> map, String name) {
 if (name == null || name.equals("")) {
 return 0;
 }

 long value = 0;
 if (map.containsKey(name) == false) {
 return 0;
 }

 Object obj = map.get(name);
 if (obj == null) {
 return 0;
 }

 if (!(obj instanceof Long)) {
 try {
 value = Long.parseLong(obj.toString());
 } catch (Exception ex) {
 ex.printStackTrace();
 System.err.println("name[" + name + "]对应的值不是数字,返回0");
 value = 0;
 }
 } else {
 value = ((Long) obj).longValue();
 obj = null;
 }

 return value;
 }

 /**
 * 获取Float型值
 *
 * @param name
 *  键值名称
 * @return 若不存在,或转换失败,则返回0
 */
 public static float getFloat(Map<&#63;, &#63;> map, String name) {
 if (name == null || name.equals("")) {
 return 0;
 }

 float value = 0;
 if (map.containsKey(name) == false) {
 return 0;
 }

 Object obj = map.get(name);
 if (obj == null) {
 return 0;
 }

 if (!(obj instanceof Float)) {
 try {
 value = Float.parseFloat(obj.toString());
 } catch (Exception ex) {
 ex.printStackTrace();
 System.err.println("name[" + name + "]对应的值不是数字,返回0");
 value = 0;
 }
 } else {
 value = ((Float) obj).floatValue();
 obj = null;
 }

 return value;
 }

 /**
 * 获取Double型值
 *
 * @param name
 *  键值名称
 * @return 若不存在,或转换失败,则返回0
 */
 public static double getDouble(Map<&#63;, &#63;> map, String name) {
 if (name == null || name.equals("")) {
 return 0;
 }

 double value = 0;
 if (map.containsKey(name) == false) {
 return 0;
 }

 Object obj = map.get(name);
 if (obj == null) {
 return 0;
 }

 if (!(obj instanceof Double)) {
 try {
 value = Double.parseDouble(obj.toString());
 } catch (Exception ex) {
 ex.printStackTrace();
 System.err.println("name[" + name + "]对应的值不是数字,返回0");
 value = 0;
 }
 } else {
 value = ((Double) obj).doubleValue();
 obj = null;
 }

 return value;
 }

 /**
 * 获取Bool值
 *
 * @param name
 *  键值名称
 * @return 若不存在,或转换失败,则返回false
 */
 public static boolean getBoolean(Map<&#63;, &#63;> map, String name) {
 if (name == null || name.equals("")) {
 return false;
 }

 boolean value = false;
 if (map.containsKey(name) == false) {
 return false;
 }
 Object obj = map.get(name);
 if (obj == null) {
 return false;
 }

 if (obj instanceof Boolean) {
 return ((Boolean) obj).booleanValue();
 }

 value = Boolean.valueOf(obj.toString()).booleanValue();
 obj = null;
 return value;
 }
}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。


推荐阅读
  • 在Docker中,将主机目录挂载到容器中作为volume使用时,常常会遇到文件权限问题。这是因为容器内外的UID不同所导致的。本文介绍了解决这个问题的方法,包括使用gosu和suexec工具以及在Dockerfile中配置volume的权限。通过这些方法,可以避免在使用Docker时出现无写权限的情况。 ... [详细]
  • EPICS Archiver Appliance存储waveform记录的尝试及资源需求分析
    本文介绍了EPICS Archiver Appliance存储waveform记录的尝试过程,并分析了其所需的资源容量。通过解决错误提示和调整内存大小,成功存储了波形数据。然后,讨论了储存环逐束团信号的意义,以及通过记录多圈的束团信号进行参数分析的可能性。波形数据的存储需求巨大,每天需要近250G,一年需要90T。然而,储存环逐束团信号具有重要意义,可以揭示出每个束团的纵向振荡频率和模式。 ... [详细]
  • 云原生边缘计算之KubeEdge简介及功能特点
    本文介绍了云原生边缘计算中的KubeEdge系统,该系统是一个开源系统,用于将容器化应用程序编排功能扩展到Edge的主机。它基于Kubernetes构建,并为网络应用程序提供基础架构支持。同时,KubeEdge具有离线模式、基于Kubernetes的节点、群集、应用程序和设备管理、资源优化等特点。此外,KubeEdge还支持跨平台工作,在私有、公共和混合云中都可以运行。同时,KubeEdge还提供数据管理和数据分析管道引擎的支持。最后,本文还介绍了KubeEdge系统生成证书的方法。 ... [详细]
  • 本文介绍了设计师伊振华受邀参与沈阳市智慧城市运行管理中心项目的整体设计,并以数字赋能和创新驱动高质量发展的理念,建设了集成、智慧、高效的一体化城市综合管理平台,促进了城市的数字化转型。该中心被称为当代城市的智能心脏,为沈阳市的智慧城市建设做出了重要贡献。 ... [详细]
  • 本文介绍了数据库的存储结构及其重要性,强调了关系数据库范例中将逻辑存储与物理存储分开的必要性。通过逻辑结构和物理结构的分离,可以实现对物理存储的重新组织和数据库的迁移,而应用程序不会察觉到任何更改。文章还展示了Oracle数据库的逻辑结构和物理结构,并介绍了表空间的概念和作用。 ... [详细]
  • 目录实现效果:实现环境实现方法一:基本思路主要代码JavaScript代码总结方法二主要代码总结方法三基本思路主要代码JavaScriptHTML总结实 ... [详细]
  • CSS3选择器的使用方法详解,提高Web开发效率和精准度
    本文详细介绍了CSS3新增的选择器方法,包括属性选择器的使用。通过CSS3选择器,可以提高Web开发的效率和精准度,使得查找元素更加方便和快捷。同时,本文还对属性选择器的各种用法进行了详细解释,并给出了相应的代码示例。通过学习本文,读者可以更好地掌握CSS3选择器的使用方法,提升自己的Web开发能力。 ... [详细]
  • 本文主要解析了Open judge C16H问题中涉及到的Magical Balls的快速幂和逆元算法,并给出了问题的解析和解决方法。详细介绍了问题的背景和规则,并给出了相应的算法解析和实现步骤。通过本文的解析,读者可以更好地理解和解决Open judge C16H问题中的Magical Balls部分。 ... [详细]
  • [译]技术公司十年经验的职场生涯回顾
    本文是一位在技术公司工作十年的职场人士对自己职业生涯的总结回顾。她的职业规划与众不同,令人深思又有趣。其中涉及到的内容有机器学习、创新创业以及引用了女性主义者在TED演讲中的部分讲义。文章表达了对职业生涯的愿望和希望,认为人类有能力不断改善自己。 ... [详细]
  • baresip android编译、运行教程1语音通话
    本文介绍了如何在安卓平台上编译和运行baresip android,包括下载相关的sdk和ndk,修改ndk路径和输出目录,以及创建一个c++的安卓工程并将目录考到cpp下。详细步骤可参考给出的链接和文档。 ... [详细]
  • 知识图谱——机器大脑中的知识库
    本文介绍了知识图谱在机器大脑中的应用,以及搜索引擎在知识图谱方面的发展。以谷歌知识图谱为例,说明了知识图谱的智能化特点。通过搜索引擎用户可以获取更加智能化的答案,如搜索关键词"Marie Curie",会得到居里夫人的详细信息以及与之相关的历史人物。知识图谱的出现引起了搜索引擎行业的变革,不仅美国的微软必应,中国的百度、搜狗等搜索引擎公司也纷纷推出了自己的知识图谱。 ... [详细]
  • 使用在线工具jsonschema2pojo根据json生成java对象
    本文介绍了使用在线工具jsonschema2pojo根据json生成java对象的方法。通过该工具,用户只需将json字符串复制到输入框中,即可自动将其转换成java对象。该工具还能解析列表式的json数据,并将嵌套在内层的对象也解析出来。本文以请求github的api为例,展示了使用该工具的步骤和效果。 ... [详细]
  • 电话号码的字母组合解题思路和代码示例
    本文介绍了力扣题目《电话号码的字母组合》的解题思路和代码示例。通过使用哈希表和递归求解的方法,可以将给定的电话号码转换为对应的字母组合。详细的解题思路和代码示例可以帮助读者更好地理解和实现该题目。 ... [详细]
  • 本文介绍了使用Java实现大数乘法的分治算法,包括输入数据的处理、普通大数乘法的结果和Karatsuba大数乘法的结果。通过改变long类型可以适应不同范围的大数乘法计算。 ... [详细]
  • 本文介绍了九度OnlineJudge中的1002题目“Grading”的解决方法。该题目要求设计一个公平的评分过程,将每个考题分配给3个独立的专家,如果他们的评分不一致,则需要请一位裁判做出最终决定。文章详细描述了评分规则,并给出了解决该问题的程序。 ... [详细]
author-avatar
伤心脑残猪_940
这个家伙很懒,什么也没留下!
PHP1.CN | 中国最专业的PHP中文社区 | DevBox开发工具箱 | json解析格式化 |PHP资讯 | PHP教程 | 数据库技术 | 服务器技术 | 前端开发技术 | PHP框架 | 开发工具 | 在线工具
Copyright © 1998 - 2020 PHP1.CN. All Rights Reserved | 京公网安备 11010802041100号 | 京ICP备19059560号-4 | PHP1.CN 第一PHP社区 版权所有