java - 将一个日历实例分配给另一个实例的问题

Question

我有两个日历实例变量，一个全局声明，另一个局部声明。现在假设我将一个日历实例分配给另一个实例，例如

Calendar m_CalGlobally = Calendar.getInstance();

Calendar calLocally = m_CalGlobally;

现在我的问题是，如果我对 calLocally 变量进行任何更改，相同的更改会出现在 m_CalGlobally 实例变量中，为什么会发生这种情况，以及如何分配它。

Answer 1

绝对不行。这样做

 Calendar m_CalGlobally = Calendar.getInstance();

 Calendar calLocally = (Calendar)m_CalGlobally.clone(); // Proper way to assign this.
//This will give you calender with same properties and also the changes of it wont be reflected on m_CalGlobally because assigning with equal operator make them point to same reference.