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  • java 并发生成商品编号

    package skdapp.cn.stream.common.generator;
    
    import java.time.Instant;
    import java.util.HashSet;
    import java.util.Objects;
    import java.util.Set;
    import java.util.UUID;
    import java.util.concurrent.Callable;
    import java.util.concurrent.ExecutionException;
    import java.util.concurrent.FutureTask;
    import java.util.concurrent.ThreadLocalRandom;
    import java.util.concurrent.atomic.AtomicInteger;
    
    import org.apache.commons.lang3.time.FastDateFormat;
    import org.springframework.util.StopWatch;
    
    /**
     * 订单编号策略
     * 
     * @project common-utils
     * @fileName ODDGenerator.java
     * @Description
     * @author light-zhang
     * @date 2018年5月11日
     * @version 1.0.0
     */
    public abstract class ODDGenerator {
        private static final FastDateFormat pattern = FastDateFormat.getInstance("yyyyMMddHHmmss");
        private static final AtomicInteger atomicInteger = new AtomicInteger(1);
        private static ThreadLocal<StringBuilder> threadLocal = new ThreadLocal<StringBuilder>();
    
        /**
         * 长码生成策略
         *  20201116114351753590384993
         * @param lock uuid
         * @return
         */
        public static String getC(String lock) {
            if (Objects.isNull(threadLocal.get())) {
                lock = Objects.isNull(lock) ? UUID.randomUUID().toString() : lock;
                StringBuilder builder = new StringBuilder(pattern.format(Instant.now().toEpochMilli()));// 取系统当前时间作为订单号前半部分
                builder.append(Math.abs(lock.hashCode()));// HASH-CODE
                builder.append(atomicInteger.getAndIncrement());// 自增顺序
                threadLocal.set(builder);
            } 
            return threadLocal.get().toString();
        }
    
        /**
         * 短码生成策略
         * 1307891882965
         * @param lock
         * @return
         */
        public static String getD(String lock) { 
            if (Objects.isNull(threadLocal.get())) {
                lock = Objects.isNull(lock) ? UUID.randomUUID().toString() : lock;
                StringBuilder builder = new StringBuilder(ThreadLocalRandom.current().nextInt(0, 999)); // 随机数
                builder.append(Math.abs(lock.hashCode()));// HASH-CODE
                builder.append(atomicInteger.getAndIncrement());// 自增顺序
                threadLocal.set(builder);
            } 
            return threadLocal.get().toString();
        }
    
        /**
         * 1000个线程并发测试
         * 
         * @param args
         * @throws InterruptedException
         * @throws ExecutionException
         */
        public static void main(String[] args) throws InterruptedException, ExecutionException {
            Set<String> set = new HashSet<String>();
            FutureTask<String> task = null;
            StopWatch watchTime = new StopWatch();
            watchTime.start();
            for (int i = 0; i < 1000; i++) {
                Callable<String> callable = new Callable<String>() {
                    @Override
                    public String call() throws Exception {
                        // System.out.println("当前线程:>>>>> ".concat(Thread.currentThread().getId()+""));
                        //return getC(null);
                        return getD(null);
                    }
                };
                task = new FutureTask<String>(callable);
                new Thread(task).start();
                set.add(task.get());
                System.out.println(task.get());
            }
            watchTime.stop();
            System.out.println(watchTime.getTotalTimeMillis());
            System.out.println(set.size());
        } 
    }
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  • 原文地址:https://www.cnblogs.com/light-zhang/p/9881359.html
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