生成唯一ID

àì夳堔傛蜴生んèń 2022-07-14 07:50 266阅读 0赞

因为业务需求所以需要一个ID生成器，要求生成器16位ID唯一。UUID太长不适合需求，所以琢磨了一个。总体思路就是，借助UUID（毕竟人家全球唯一，自己写太麻烦了）生成一个baseID，然后搞个位权出来进行数据整合算出所需要的ID。后来经过领导的开导又把生成器变为动态生成，其实就是可生成14到32位任意ID。下面直接上代码了。

package com.ecej.admin.common.utils;
    
    import java.io.Serializable;
    import java.util.UUID;
    
    /**
     * 
     * 
     * @author QIANG
     */
    public abstract class UniCodeUtil implements Serializable {
    
    	private static final long serialVersionUID = -5628028113003022356L;
    
    	private static final int MAX_SIZE = 25;
    	private static final int MIN_SIZE = 14;
    	private static final int BASE_SIZE = 2;
    
    	/**
    	 * 默认生成RCID 12位
    	 * 
    	 * @return
    	 */
    	public static String rand() {
    		return rand(16);
    	}
    
    	/**
    	 * 根据传入值生成相应位数随机码
    	 * 
    	 * @param offset 最大生成40位，最小生成14位 (位权基础系数为4) 4 6 8 1 2 3
    	 * 
    	 * @return
    	 */
    	public static String rand(int offset) {
    
    		if (offset > MAX_SIZE || offset < MIN_SIZE) {
    			return "";
    		}
    		int div = offset / 10;
    		int bitSize = BASE_SIZE + (div << 2 >> 1);
    		int baseSize = offset - bitSize;
    
    		String baseID = randomBaseID(baseSize);
    
    		StringBuilder rcid = new StringBuilder(baseID);
    		String rv = bitWeight(bitSize);
    		char[] ch = rv.toCharArray();
    		for (char c : ch) {
    			rcid.insert(Character.getNumericValue(c), c);
    		}
    		return rcid.toString().toUpperCase();
    	}
    
    	/**
    	 * 根据UUID生成随机指定位数位ID
    	 * 
    	 * @return
    	 */
    	public static String randomBaseID(int baseSize) {
    		UUID uid = UUID.randomUUID();
    		long idx = uid.getLeastSignificantBits();
    		StringBuilder buff = new StringBuilder();
    		for (int i = 0; i < 12; i++) {
    			buff.append(toa(0x1F & idx));
    			idx >>>= 5;
    		}
    		long idxb = uid.getMostSignificantBits();
    		buff.append(toa((idxb & 0x1) == 0 ? idx : idx + 0x10));
    		idx = (idxb >>> 1);
    		for (int i = 0; i < 13; i++) {
    			buff.append(toa(0x1F & idx));
    			idx >>>= 5;
    		}
    		return buff.reverse().toString().substring(0, baseSize);
    	}
    
    	/**
    	 * 获取位权数
    	 * 
    	 * @return
    	 */
    	private static String bitWeight(int bitSize) {
    		String str = String.valueOf(Math.random()).substring(2);
    		while (str.length() < bitSize || str.indexOf('-') > 0) {
    			str = String.valueOf(Math.random()).substring(2);
    		}
    		return str.substring(0, bitSize);
    	}
    
    	/**
    	 * 生成可见字符
    	 * 
    	 * @param lidx
    	 * @return
    	 */
    	private static char toa(long lidx) {
    		if (lidx < 10) {
    			return (char) (0x30 + lidx);
    		}
    		lidx += (0x41 - 10);
    		int[] skips = { 0x49, 0x4f, 0x57, 0x5a };
    		for (int ch : skips) {
    			if (lidx < ch) {
    				break;
    			}
    			lidx++;
    		}
    		return (char) lidx;
    	}
    }