多线程获取有序随机数字(同步)

需求:

引用

获取有序随机数字序列,在服务器上全局共享最新的序列.有序随机数字生成规则为 前N位变长递增唯一数字 + (后缀)固定M位随机数字. 例如: 1000 + 1234 -> 10001234; 1001 + 4321 -> 10014321; 1002 + 4567 -> 10024567

测试类:

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class DigitServiceTest implements Runnable {

	private DigitNumServiceInterface employeeService;

	@Before
	public void setUp() throws Exception {
	}

	@Test
	public void digitNumTest() {
		for (int i = 0; i < 15; i++)
			new Thread(new DigitServiceTest()).start();
	}

	@After
	public void tearDown() throws Exception {
	}

	public void run() {
		employeeService = new EmployeeServiceImpl();
		System.out.println(Thread.currentThread() + " empDigit->" + employeeService.getCurrentDigitNum());
	}

	@Test
	public void normalTest() {
		employeeService = new EmployeeServiceImpl();
		System.out.println(Thread.currentThread() + " empDigit->" + employeeService.getCurrentDigitNum());
	}
}

接口:

public interface DigitNumServiceInterface {
	/**
	 * 如果系统中还没有数字帐号记录,以此为起始默认前缀.
	 * 数字帐号生成规则为前N位唯一数字 + DEFAULT_DIGIT_NUM_SUFFIX_LENGTH位随机数字
	 */
	Integer DEFAULT_DIGIT_NUM_START = 1000;
	/**
	 * 数字帐号后缀随机数字长度.
	 */
	Integer DEFAULT_DIGIT_NUM_SUFFIX_LENGTH = 4;
	/** 数字帐号初始长度 DEFAULT_DIGIT_NUM_SUFFIX_LENGTH + DEFAULT_DIGIT_NUM_START.length*/
	Integer DEFAULT_DIGIT_NUM_MIN_LENGTH = 8;

	/** 获取数据库中最新的数字帐号*/
	String getLastDigitNumFromDB();

	/**获取当前按规则生成好的数字帐号*/
	String getCurrentDigitNum();

	/** 根据最新的数字帐号获取下一个数字帐号的前缀*/
	String getNextDigitNumPrefix(String lastDigitNum);
}

Mock类:

import com.srt.vas.lt.util.StringUtil;

public class EmployeeServiceImpl implements DigitNumServiceInterface {
	static String CURRENT_DIGIT_NUM;

	/**获取当前按规则生成好的数字帐号,生成失败返回null */
	public String getCurrentDigitNum() {
		synchronized (DigitNumServiceInterface.DEFAULT_DIGIT_NUM_SUFFIX_LENGTH) {//同步锁
			String currentDigitNum = null;
			if (CURRENT_DIGIT_NUM == null) {//查询当前系统最新数字帐号
				System.out.println("isNull");
				currentDigitNum = getLastDigitNumFromDB();
				currentDigitNum = getNextDigitNumPrefix(currentDigitNum);
			} else {
				currentDigitNum = getNextDigitNumPrefix(CURRENT_DIGIT_NUM);
			}
			if (currentDigitNum != null)
				currentDigitNum += StringUtil.randomNumeric(DEFAULT_DIGIT_NUM_SUFFIX_LENGTH);
			//				currentDigitNum += "0000";
			CURRENT_DIGIT_NUM = currentDigitNum;
			return CURRENT_DIGIT_NUM;
		}
	}

	public String getNextDigitNumPrefix(String lastDigitNum) {
		if (lastDigitNum == null)
			return "" + (DEFAULT_DIGIT_NUM_START + 1);
		if (lastDigitNum.length() < DEFAULT_DIGIT_NUM_MIN_LENGTH)
			return null;
		if (lastDigitNum.length() >= DEFAULT_DIGIT_NUM_MIN_LENGTH)
			return ""
					+ (Integer.parseInt(lastDigitNum.substring(0, lastDigitNum.length()
							- DEFAULT_DIGIT_NUM_SUFFIX_LENGTH)) + 1);
		return null;
	}

	public String getLastDigitNumFromDB() {
		return "100100000";
	}
}

StringUtil:

import java.util.Collection;
import java.util.Map;
import java.util.Random;

import org.apache.commons.lang.RandomStringUtils;//apache common

public class StringUtil{
	/**
	 * 判断字符是否为空,为null,是否由空白字符组成.
	 * @param str
	 * @return 为空,null,全部空白字符时返回true,否则false.
	 */
	public static boolean isEmpty(String str) {
		return str == null || str.matches("^\\s*$");
	}

	/**
	 * 为null返回true.
	 * @see StringUtil#isEmpty(String)
	 * @param l
	 * @return
	 */
	public static boolean isEmpty(Long l) {
		return l == null;
	}

	/**
	 * 为null 返回true.
	 * @param obj
	 * @return
	 */
	public static boolean isEmpty(Object obj) {
		return obj == null;
	}

	@SuppressWarnings("unchecked")
	public static boolean isEmpty(Collection c) {
		return c == null || c.isEmpty();
	}

	/**
	 * 判断是否为空
	 * @param map
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public static boolean isEmpty(Map map) {
		return map == null || map.isEmpty();
	}

	/**
	 * 返回Hql in子句风格的字符串. (Object[, Object])
	 * Exp: from DomesticCat cat where cat.name in ( 'Foo', 'Bar', 'Baz' )
	 * from DomesticCat cat where cat.name not in ( 'Foo', 'Bar', 'Baz' )
	 * @param collect
	 * @return 返回Hql in子句风格的字符串.
	 */
	public static String getHqlInStyle(Collection<Long> collect) {
		Long[] a = collect.toArray(new Long[0]);
		if (a.length == 0)
			return "";

		StringBuilder buf = new StringBuilder();
		buf.append('(');
		buf.append(a[0]);

		for (int i = 1; i < a.length; i++) {
			buf.append(", ");
			buf.append(a[i]);
		}

		buf.append(")");
		return buf.toString();
	}

	/**
	 * 生成指定长度的随机数字.
	 * @param count
	 * @return
	 */
	public static String randomNumeric(int count) {
		return RandomStringUtils.randomNumeric(count);
	}

	/**
	 * 生成长度为1,值为1-9的随机数字.
	 * @return
	 */
	public static String randomNumericBetween1And9() {
		return RandomStringUtils.random(1, "123456789");
	}

	/**
	 * 生成指定长度的随机数字,第一位不为0.
	 * @param count
	 * @return
	 */
	public static String randomNumericStartWithoutZero(int count) {
		return StringUtil.randomNumericBetween1And9() + StringUtil.randomNumeric(count - 1);
	}

	/**
	 * 密码为6位随机数字，并且第一位大于0。
	 * @return
	 */
	public static String randomNumericPassword() {
		return StringUtil.randomNumericBetween1And9() + StringUtil.randomNumeric(5);
	}
	
}