singleton

来源： https://stackoverflow.com/questions/51595827/net-core-1-1-httpclient-with-di

来源： https://stackoverflow.com/questions/8100816/suppress-a-singleton-constructor-in-java-with-powermock

来源： https://stackoverflow.com/questions/63560777/c-sharp-singleton-class-working-well-confirmation

来源： https://stackoverflow.com/questions/63560777/c-sharp-singleton-class-working-well-confirmation

来源： https://stackoverflow.com/questions/61571960/accessing-core-data-stack-in-mvvm-application

来源： https://stackoverflow.com/questions/61571960/accessing-core-data-stack-in-mvvm-application

来源： https://stackoverflow.com/questions/61571960/accessing-core-data-stack-in-mvvm-application

来源： https://stackoverflow.com/questions/53654053/android-room-avoid-passing-context-into-singleton

问题 I read many forums and posts about different style to implement single-tone pattern in java and seems "Enum are the best way to implement singletone pattern in java"!! I wonder how can i use Java Enum to implement SingleTone pattern in java with lazy-loading capability. since Enums are just classes. The first time a class is used, it gets loaded by the JVM and all of its static initialization is done. the enum members are static , so they're all going to be initialized. does anyone know how

问题 I found this code online for the singleton design pattern: class Foo { public: static Foo& getInstance() { static Foo instance; return instance; } private: Foo() {}; Foo(Foo const&); Foo& operator=(Foo const&); } I don't understand why the constructor Foo(Foo const&); and the Foo& operator=(Foo const&); are both needed. Can someone explain to me please? 回答1: Wouldn't you want the following code to fail? int main() { // Utilizes the copy constructor Foo x = Foo::getInstance(); Foo y = Foo: