ThreadLocalRandom

Bertha 。 2023-01-11 01:13 110阅读 0赞

从jdk7开始，新增了一个ThreadLocalRandom类来替代之前的Random类，相较于之前的Random类，ThreadLocalRandom基于ThreadLocal来实现，性能更好。

/**
     * A random number generator isolated to the current thread.  Like the
     * global {@link java.util.Random} generator used by the {@link
     * java.lang.Math} class, a {@code ThreadLocalRandom} is initialized
     * with an internally generated seed that may not otherwise be
     * modified. When applicable, use of {@code ThreadLocalRandom} rather
     * than shared {@code Random} objects in concurrent programs will
     * typically encounter much less overhead and contention.  Use of
     * {@code ThreadLocalRandom} is particularly appropriate when multiple
     * tasks (for example, each a {@link ForkJoinTask}) use random numbers
     * in parallel in thread pools.
     *
     * <p>Usages of this class should typically be of the form:
     * {@code ThreadLocalRandom.current().nextX(...)} (where
     * {@code X} is {@code Int}, {@code Long}, etc).
     * When all usages are of this form, it is never possible to
     * accidently share a {@code ThreadLocalRandom} across multiple threads.
     *
     * <p>This class also provides additional commonly used bounded random
     * generation methods.
     *
     * <p>Instances of {@code ThreadLocalRandom} are not cryptographically
     * secure.  Consider instead using {@link java.security.SecureRandom}
     * in security-sensitive applications. Additionally,
     * default-constructed instances do not use a cryptographically random
     * seed unless the {@linkplain System#getProperty system property}
     * {@code java.util.secureRandomSeed} is set to {@code true}.
     *
     * @since 1.7
     * @author Doug Lea
     */

粘贴一段源码的注释，使用起来也非常的简单，通过使用ThreadLocalRandom threadLocalRandom = ThreadLocalRandom.current()即可获取实例，然后通过threadLocalRandom.next\*\*即可。