O O P w i t h J a v a Y u a n b i n Wu c s @e c - PowerPoint PPT Presentation

O O P w i t h J a v a Y u a n b i n Wu c s @e c n u

O O P w i t h J a v a ● 通知 – P 月 2 日晚 9 点 r o j e c t 7 : 6 7 – 6 月 1 日复习 4 – 6 月 2 日考试 1 – 答疑 ● 6 月 2 日 1 ： 0 ： 0 0 3 0 – 1 5 0 ● 理科楼 B 9 1 1

a b s t r a c t c l a s s d e m o { p u b l i c i n t a ; d e m o ( ) { a = 1 0 ; } a b s t r a c t p u b l i c v o i d s e t ( ) ; a b s t r a c t fi n a l p u b l i c v o i d g e t ( ) ; } c l a s s T e s t e x t e n d s d e m o { p u b l i c v o i d s e t ( i n t a ) { t h i s . a = a ; } fi n a l p u b l i c v o i d g e t ( ) { S y s t e m . o u t . p r i n t l n ( " a = " + a ) ; } p u b l i c s t a t i c v o i d m a i n ( S t r i n g [ ] a r g s ) { T e s t o b j = n e w T e s t ( ) ; o b j . s e t ( 2 0 ) ; o b j . g e t ( ) ; } }

c l a s s T e s t { p u b l i c s t a t i c v o i d m a i n ( S t r i n g [ ] a r g s ) { t r y { i n t a = 0 ; S y s t e m . o u t . p r i n t l n ( " a = " + a + " \ n " ) ; i n t b = 2 0 / a ; S y s t e m . o u t . p r i n t l n ( " b = " + b ) ; } c a t c h ( A r i t h m e t i c E x c e p t i o n e ) { S y s t e m . o u t . p r i n t l n ( " D i v i d e b y z e r o e r r o r " ) ; } fi n a l l y { S y s t e m . o u t . p r i n t l n ( " i n s i d e t h e fi n a l l y b l o c k " ) ; } } }

p u b l i c c l a s s T e s t { p r i v a t e i n t x = 1 ; p r i v a t e i n t y = 2 ; p r i v a t e s t a t i c i n t z = 3 ; p u b l i c s t a t i c v o i d m a i n ( S t r i n g [ ] a r g s ) { i n t x = 4 ; i n t y = 5 ; i n t z = 6 ; n e w T e s t ( ) . n e w I n n e r ( ) . i n i t ( ) ; } c l a s s I n n e r { v o i d i n i t ( ) { S y s t e m . o u t . p r i n t l n ( x + " " + y + " " + z ) ; } } }

i n t e r f a c e F o o { i n t x = 1 0 ; } p u b l i c c l a s s T e s t { p u b l i c s t a t i c v o i d m a i n ( S t r i n g [ ] a r g s ) { F o o . x = 2 0 ; S y s t e m . o u t . p r i n t l n ( F o o . x ) ; } }

定义一个 L 其中包含 S 对象 . 1 . i n k e d L i s t , t r i n g 编写方法遍历该 L 2 . i n k e d L i s t .

● 复习 ● I 流 / O – I n p u t S t r e a m / R e a d e r ● r e a d ( ) – O u t p u t S t r e a m / Wr i t e r ● w r i t e ( ) – 抽象 : 数据的来源 / 数据的目的地 ● B y t e A r r a y S t r e a m , F i l e S t r e a m S t r i n g S t r e a m O b j e c t S t r e a m

i m p o r t j a v a . i o . F i l e I n p u t S t r e a m ; i m p o r t j a v a . i o . F i l e O u t p u t S t r e a m ; i m p o r t j a v a . i o . I O E x c e p t i o n ; p u b l i c c l a s s C o p y B y t e s { p u b l i c s t a t i c v o i d m a i n ( S t r i n g [ ] a r g s ) t h r o w s I O E x c e p t i o n { F i l e I n p u t S t r e a m i n = n u l l ; F i l e O u t p u t S t r e a m o u t = n u l l ; t r y { i n = n e w F i l e I n p u t S t r e a m ( " x a n a d u . t x t " ) ; o u t = n e w F i l e O u t p u t S t r e a m ( " o u t a g a i n . t x t " ) ; i n t c ; w h i l e ( ( c = i n . r e a d ( ) ) ! = - 1 ) o u t . w r i t e ( c ) ; } fi n a l l y { i f ( i n ! = n u l l ) i n . c l o s e ( ) ; i f ( o u t ! = n u l l ) o u t . c l o s e ( ) ; } } }

● 装饰器 – F i l t e r I n p u t S t r e a m / F i l t e r O u t p u t S t r e a m ● B u ff e r e d I n p u t S t r e a m ● D a t a I n p u t S t r e a m F i l e I n p u t S t r e a m fi n = n e w F i l e I n p u t S t r e a m ( " x a n a d u . t x t " ) ; B u ff e r e d I n p u t S t r e a m b f = n e w B u ff e r e d I n p u t S t r e a m ( fi n ) ; D a t a I n p u t S t r e a m d i n = n e w D a t a I n p u t S t r e a m ( b f ) ; d i n . r e a d ( ) ; d i n . r e a d I n t ( ) ; d i n . r e a d D o u b l e ( ) ; F i l e O u t p u t S t r e a m f o u t = n e w F i l e O u t p u t S t r e a m ( " x a n a d u . t x t " ) ; B u ff e r e d O u t p u t S t r e a m b f = n e w B u ff e r e d O u t p u t S t r e a m ( f o u t ) ; D a t a O u t p u t S t r e a m d o u t = n e w D a t a O u t p u t S t r e a m ( b f ) ; d o u t . w r i t e ( 1 ) ; d o u t . w r i t e I n t ( 1 0 ) ; d o u t . w r i t e D o u b l e ( 3 . 1 4 ) ;

● 复习 I n p u t S t r e a m F i l t e r I n p u t S t r e a m B y t e A r r a y I n p u t S t r e a m F i l e I n p u t S t r e a m S t r i n g B u ff e r I n p u t S t r e a m B u ff e r d I n p u t S t r e a m D a t a I n p u t S t r e a m 装饰器

O O P w i t h J a v a ● 运行时类型信息 ● 泛型

R T T I ● 运行时类型信息 – R u n T i m e T y p e I n f o r m a t i o n ( R T T I ) 类 – C l a s s ● 每一个类都包含一个 C 类的对象 l a s s ● 该对象包含该类的信息 – 类名字 – 类的有哪些方法 – 类的有哪些成员

R T T I ● 每个类的静态成员 – 所有对象共享一个 C 对象 l a s s ● 每个对象调用 g 获得 C 类的对象 e t C l a s s ( ) l a s s – S t r i n g s = “ h e l l o ” ; C l a s s c = s . g e t C l a s s ( ) ; ● 每个类通过 . 获得 C 类的对象 c l a s s l a s s – C l a s s c = S t r i n g . c l a s s

R T T I ● C 类的方法 l a s s – g e t N a m e ( ) – g e t I n t e r f a c e s ( ) – g e t S u p e r c l a s s ( ) – n e w I n s t a n c e ( )