static void Main(string[] args)
{
try
{
{
for (int i = 0; i < 5; i++)
{
Student student = new Student()
{
Id = 1,
Name = "Ivan"
};
student.Study();
}
}
{
// 为了减少对象的创建， 重用对象，提升性能，所以用了单例
for (int i = 0; i < 5; i++)
{
StudentSingleton student = StudentSingleton.CreateInstance(); // new StudentSingleton()
student.Id = 1;
student.Name = "Ivan";
student.Study();
}
}
{
// 单例会导致数据被覆盖，因为student 和studentNew都指向同一个对象
StudentSingleton student = StudentSingleton.CreateInstance(); // new StudentSingleton()
student.Id = 1;
student.Name = "Ivan";
student.Study();
StudentSingleton studentNew = StudentSingleton.CreateInstance(); // new StudentSingleton()
studentNew.Id = 12;
studentNew.Name = "Ivan123";
studentNew.Study();
}
{
// 1. 避免重复创建对象，重复调用构造函数问题 -- 内存拷贝
// 2. 避免同一个对象覆盖的问题 -- 不同对象
StudentPrototype student = StudentPrototype.CreateInstance(); // new StudentSingleton()
student.Id = 1;
student.Name = "Ivan";
student.Study();
StudentPrototype studentNew = StudentPrototype.CreateInstance(); // new StudentSingleton()
studentNew.Id = 12;
studentNew.Name = "Ivan123";
studentNew.Study();
}
{
StudentPrototype student = StudentPrototype.CreateInstance(); // new StudentSingleton()
student.Id = 1;
student.Name = "Ivan";
student.Study();
StudentPrototype studentNew = StudentPrototype.CreateInstance(); // new StudentSingleton()
studentNew.Id = 12;
studentNew.Name = "Ivan123";
studentNew.Study();
StudentPrototype studentDouble = StudentPrototype.CreateInstance(); // new StudentSingleton()
studentDouble.Id = 123;
studentDouble.Name = "Ivan12342";
// 会覆盖StudentPrototype中初始化的班级信息，因为浅拷贝只拷贝了引用地址
studentDouble.Class.ClassId = 2;
studentDouble.Class.Name = "Advanced";
studentDouble.Study();
// 内存拷贝时 引用属性是拷贝的引用地址, 多个student的class指向的都是同一块内存
// 所以一个变化，全部都会变化
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
