随笔分类 -  JAVA

[JAVA]线程安全volatile
摘要：锁提供两种特性： 1.互斥(mutual exclusion): 多线程只有一个能操作 2.可见性(visibility)：锁释放之前的修改对于随后获得该锁的另一个线程是可见的 volatile只具有可见性，不具有互斥性。 阅读全文
posted @ 2017-07-24 22:37 firerdong 阅读(129) 评论(0) 推荐(0)
[JAVA]String StringBuffer StringBuilder
摘要：String 字符串常量 StringBuffer、StringBuilder 字符串变量 字符串拼接时的速度：StringBuilder > StringBuffer > String StringBuffer线程安全 StringBuilder线程不安全，所以快 而String时创建新的字符串， 阅读全文
posted @ 2016-07-24 06:52 firerdong 阅读(117) 评论(0) 推荐(0)
[JAVA]随机省市
摘要：String citys[] = {"北京","广东","山东","江苏","河南","上海","河北","浙江","香港","山西","陕西","湖南","重庆","福建","天津","云南","四川","广西","安徽&quo 阅读全文
posted @ 2016-07-19 15:03 firerdong 阅读(1974) 评论(1) 推荐(1)