java常用工具类 UUID、Map工具类

 更新时间:2019年05月30日 11:42:31   作者:远方©  
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.
 * <p/>
 * <p>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).
 * <p/>
 * <p>The layout of a variant 2 (Leach-Salz) UUID is as follows:
 * <p/>
 * The most significant long consists of the following unsigned fields:
 * <pre>
 * 0xFFFFFFFF00000000 time_low
 * 0x00000000FFFF0000 time_mid
 * 0x000000000000F000 version
 * 0x0000000000000FFF time_hi
 * </pre>
 * The least significant long consists of the following unsigned fields:
 * <pre>
 * 0xC000000000000000 variant
 * 0x3FFF000000000000 clock_seq
 * 0x0000FFFFFFFFFFFF node
 * </pre>
 * <p/>
 * <p>The variant field contains a value which identifies the layout of
 * the <tt>UUID</tt>. The bit layout described above is valid only for
 * a <tt>UUID</tt> with a variant value of 2, which indicates the
 * Leach-Salz variant.
 * <p/>
 * <p>The version field holds a value that describes the type of this
 * <tt>UUID</tt>. 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.
 * <p/>
 * <p>For more information including algorithms used to create <tt>UUID</tt>s,
 * see the Internet-Draft <a href="http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-03.txt" rel="external nofollow" >UUIDs and GUIDs</a>
 * or the standards body definition at
 * <a href="http://www.iso.ch/cate/d2229.html" rel="external nofollow" >ISO/IEC 11578:1996</a>.
 *
 * @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 <tt>UUID</tt> using the specified data.
 * <tt>mostSigBits</tt> is used for the most significant 64 bits
 * of the <tt>UUID</tt> and <tt>leastSigBits</tt> becomes the
 * least significant 64 bits of the <tt>UUID</tt>.
 *
 * @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.
 * <p/>
 * The <code>UUID</code> is generated using a cryptographically strong
 * pseudo random number generator.
 *
 * @return a randomly generated <tt>UUID</tt>.
 */
 @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) <tt>UUID</tt> based on
 * the specified byte array.
 *
 * @param name a byte array to be used to construct a <tt>UUID</tt>.
 * @return a <tt>UUID</tt> 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 <tt>UUID</tt> from the string standard representation as
 * described in the {@link #toString} method.
 *
 * @param name a string that specifies a <tt>UUID</tt>.
 * @return a <tt>UUID</tt> 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 <tt>UUID</tt>. The version
 * number describes how this <tt>UUID</tt> was generated.
 * <p/>
 * The version number has the following meaning:<p>
 * <ul>
 * <li>1 Time-based UUID
 * <li>2 DCE security UUID
 * <li>3 Name-based UUID
 * <li>4 Randomly generated UUID
 * </ul>
 *
 * @return the version number of this <tt>UUID</tt>.
 */
 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 <tt>UUID</tt>. The variant
 * number describes the layout of the <tt>UUID</tt>.
 * <p/>
 * The variant number has the following meaning:<p>
 * <ul>
 * <li>0 Reserved for NCS backward compatibility
 * <li>2 The Leach-Salz variant (used by this class)
 * <li>6 Reserved, Microsoft Corporation backward compatibility
 * <li>7 Reserved for future definition
 * </ul>
 *
 * @return the variant number of this <tt>UUID</tt>.
 */
 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.
 * <p/>
 * <p>The 60 bit timestamp value is constructed from the time_low,
 * time_mid, and time_hi fields of this <tt>UUID</tt>. The resulting
 * timestamp is measured in 100-nanosecond units since midnight,
 * October 15, 1582 UTC.<p>
 * <p/>
 * The timestamp value is only meaningful in a time-based UUID, which
 * has version type 1. If this <tt>UUID</tt> 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.
 * <p/>
 * <p>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.<p>
 * <p/>
 * 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 <tt>UUID</tt>.
 * @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.
 * <p/>
 * <p>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.<p>
 * <p/>
 * 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 <tt>UUID</tt>.
 * @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 <code>String</code> object representing this
 * <code>UUID</code>.
 * <p/>
 * <p>The UUID string representation is as described by this BNF :
 * <pre>
 * UUID   = <time_low> "-" <time_mid> "-"
 *    <time_high_and_version> "-"
 *    <variant_and_sequence> "-"
 *    <node>
 * time_low  = 4*<hexOctet>
 * time_mid  = 2*<hexOctet>
 * time_high_and_version = 2*<hexOctet>
 * variant_and_sequence = 2*<hexOctet>
 * node   = 6*<hexOctet>
 * hexOctet  = <hexDigit><hexDigit>
 * hexDigit  =
 * "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
 * | "a" | "b" | "c" | "d" | "e" | "f"
 * | "A" | "B" | "C" | "D" | "E" | "F"
 * </pre>
 *
 * @return a string representation of this <tt>UUID</tt>.
 */
 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 <code>UUID</code>.
 *
 * @return a hash code value for this <tt>UUID</tt>.
 */
 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
 * <tt>true</tt> if and only if the argument is not
 * <tt>null</tt>, is a <tt>UUID</tt> object, has the same variant,
 * and contains the same value, bit for bit, as this <tt>UUID</tt>.
 *
 * @param obj the object to compare with.
 * @return <code>true</code> if the objects are the same;
 *  <code>false</code> 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.
 * <p/>
 * <p>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 <tt>UUID</tt> to which this <tt>UUID</tt> is to be compared.
 * @return -1, 0 or 1 as this <tt>UUID</tt> is less than, equal
 *  to, or greater than <tt>val</tt>.
 */
 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 ? -1 :
  (this.mostSigBits > val.mostSigBits ? 1 :
   (this.leastSigBits < val.leastSigBits ? -1 :
    (this.leastSigBits > val.leastSigBits ? 1 :
     0))));
 }

 /**
 * Reconstitute the <tt>UUID</tt> 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<?, ?> 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<?, ?> 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<?, ?> 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<?, ?> 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<?, ?> 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<?, ?> 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脚本之家。

相关文章

  • Spring框架学习之Spring @Autowired实现自动装配的代码

    Spring框架学习之Spring @Autowired实现自动装配的代码

    自动装配就是说,你不用手动实现bean之间的组合关系,只要使用了@Autowired注解,程序就会自动的注入这个需要的bean,前提是你的Spring容器有这个bean,这篇文章主要介绍了Spring @Autowired实现自动装配,需要的朋友可以参考下
    2021-12-12
  • Java8中的Stream 流实践操作

    Java8中的Stream 流实践操作

    这篇文章主要介绍了Java8中的Stream 流实践操作,Stream 是 java8 中处理集合的抽象概念,可以执行非常复杂的查询、过滤和映射数据等操作,下文更多相关资料介绍,需要的朋友可以参考一下
    2022-05-05
  • 值得收藏的2017年Java开发岗位面试题

    值得收藏的2017年Java开发岗位面试题

    这篇文章主要为大家推荐一份值得收藏的2017年Java开发岗位面试题,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
    2017-08-08
  • SpringBoot如何接收Post请求Body里面的参数

    SpringBoot如何接收Post请求Body里面的参数

    这篇文章主要介绍了SpringBoot如何接收Post请求Body里面的参数,具有很好的参考价值,希望对大家有所帮助。如有错误或未考虑完全的地方,望不吝赐教
    2022-03-03
  • ES模糊查询失效的坑以及解决方案

    ES模糊查询失效的坑以及解决方案

    ES的查询原理是按分词建立索引,根据要保存的内容先分词,然后按照分词的结果建立索引,这篇文章主要给大家介绍了关于ES模糊查询失效的坑及解决方案的相关资料,需要的朋友可以参考下
    2023-09-09
  • 详解JAVA 函数式编程

    详解JAVA 函数式编程

    这篇文章主要介绍了JAVA 函数式编程的相关资料,文中讲解非常细致,代码帮助大家更好的理解和学习,感兴趣的朋友可以了解下
    2020-07-07
  • Mockito mock Kotlin Object类方法报错解决方法

    Mockito mock Kotlin Object类方法报错解决方法

    这篇文章主要介绍了Mockito mock Kotlin Object类方法报错解决方法,本篇文章通过简要的案例,讲解了该项技术的了解与使用,以下就是详细内容,需要的朋友可以参考下
    2021-09-09
  • 基于JDK8总结java中的interrupt

    基于JDK8总结java中的interrupt

    本文是基于JDK8总结java中的interrupt知识,需要的朋友可以参考下
    2017-12-12
  • Java:

    Java:"失效"的private修饰符

    本文主要介绍Java 失效的private修饰符,这里整理了相关资料说明private 修饰符的作用,如何使用并与C++ 做比较,有兴趣的小伙伴可以参考下
    2016-08-08
  • 阿里、华为、腾讯Java技术面试题精选

    阿里、华为、腾讯Java技术面试题精选

    这篇文章主要为大家分享了阿里、华为、腾讯Java技术面试题精选,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
    2017-11-11

最新评论