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Item3:Enforce the singleton property with a private constructor or an enum type采用枚举类型(ENUM)实现单例模式。public enum Elvis { INSTANCE; public void ... 阅读全文
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Item2:Consider a builder when faced with many constructor parameters当构造方法有多个参数时,可以考虑使用builder方式进行处理。实例代码:public class NutritionFacts { private fina... 阅读全文
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SQL> set autotraceUsage: SET AUTOT[RACE] {OFF | ON | TRACE[ONLY]} [EXP[LAIN]] [STAT[ISTICS]]SQL> set autotrace onSP2-0618: Cannot find the Session Ide... 阅读全文
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SQL> conn scott/tigerERROR:ORA-28002: the password will expire within 1 daysConnected.SQL> conn /as sysdbaConnected.SQL> alter user scott identified b... 阅读全文