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自动类型转换:
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多态下引用数据类型的类型转换
强制类型转换
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案例:
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定义usb接口:
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定义鼠标和键盘的usb实现类,并有自己特有的方法,重写usb接口的方法,里面穿插了多态
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创建电脑类,把usb接口揉和进去,利用多态强制性转换实现 鼠标、键盘特有功能
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调用:
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内部类:
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静态内部类:
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成员内部类:
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匿名内部类(重点):
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不需要创建子类对象:
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匿名内部类常见的实用形式:
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Object 类:
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equals方法:
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重写equals,进行内容比较:
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右键可以自动生成equals重写内容:
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objects:
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stringBuilder:
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性能比较:
string浪费内存,一直new对象,然后丢弃
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案例:
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Math
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Sysrem类
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BigDecimal:
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调方法得到对象:
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