Java中內部類的騷操作
- 2019 年 10 月 3 日
- 筆記
10.1 ???????
???10.1-1 ??
public class Parcel1 { public class Contents{ private int value = 0;? public int getValue(){ return value; } }}
???????????????,???????????????????????Contents??????????
???????10.1-1?????????????Contents??????
???10.1-2 ??
public class Parcel1 {? public class Contents{ private int value = 0;? public int getValue(){ return value; } }? public Contents contents(){ return new Contents(); }? public static void main(String[] args) { Parcel1 p1 = new Parcel1(); Parcel1.Contents pc1 = p1.contents(); System.out.println(pc1.getValue()); }}
????? 0
???????????????????????Contents??????????Contents??????????.?????????????????????????Parcel1.Contents pc1 = p1.contents();??????pc1 ???????????Contents??????
?????????????10.1-2 ??contents?????????pc1???????
????????????????????????????
10.2 ?????????
??????????????????????????????????????????????????????????????????????????????????????????????????????10.2-1
public class Parcel2 {? private static int i = 11;? public class Parcel2Inner {? public Parcel2Inner(){ i++; }? public int getValue(){ return i; }? }? public Parcel2Inner parcel2Inner(){ return new Parcel2Inner(); }? public static void main(String[] args) { Parcel2 p2 = new Parcel2(); for(int i = 0;i < 5;i++){ p2.parcel2Inner(); } System.out.println("p2.i = " + p2.i); }}
????? 16
??????????????????????????????????????????????Parcel2Inner ??????Parcel2??i????????????????
????????????????????????????????????????????????10.2-2
public class Parcel3 {? public class Contents {? public Parcel3 dotThis(){ return Parcel3.this; }? public String toString(){ return "Contents"; } }? public Parcel3 contents(){ return new Contents().dotThis(); }? public String toString(){ return "Parcel3"; }? public static void main(String[] args) { Parcel3 pc3 = new Parcel3(); Contents c = pc3.new Contents(); Parcel3 parcel3 = pc3.contents(); System.out.println(pc3); System.out.println(c); System.out.println(parcel3); }}
??: Parcel3 Contents Parcel3
????????Parcel3?????????Contents,???????????dotThis(),???????????????,????????contents()???????????????????
10.3 ????????
?????????????????????????????????????????????????????????????????????? ??10.3-1
public interface Animal {? void eat();}?public class Parcel4 {? private class Dog implements Animal {? public void eat() { System.out.println("???"); } }? public Animal getDog(){ return new Dog(); }? public static void main(String[] args) { Parcel4 p4 = new Parcel4(); //Animal dog = p4.new Dog(); Animal dog = p4.getDog(); dog.eat(); }}
??? ???
?????????????Dog??private?????????????????????????????????? ??????????Parcel4 ?public???Parcel4???????????????Animal??????Parcel4???????Dog????Dog?????Animal?????getDog()???????Animal?????????????????????????
10.4 ????????????????
????????????????????????????????????????????????????????? ???????????????
1.???????????????????????????????????
2.??????????????????????????????????????????
3.???…
??????????????
•??????????(?????)•???????????????????????(?????)•???????????(?????)•??????????????????•???????????????•??????????????????•??????????????????
public class Parcel5 { private Destination destination(String s){? class PDestination implements Destination{? String label;? public PDestination(String whereTo){ label = whereTo; }? public String readLabel() { return label; } } return new PDestination(s); }? public static void main(String[] args) { Parcel5 p5 = new Parcel5(); Destination destination = p5.destination("China"); System.out.println(destination.readLabel()); }}?? ? China
???????????????????????????????????????????????????????????????,?????????????Debugger??????????p5.destination(“China”)????????return new PDestination(s)??????PDestination?????????????????????????????????????????????????? ?: ????????????????
•???????????????????????
public class Parcel6 { // ?????? private void eatCoconut(boolean flag){ // ????????? if(flag){ class Coconut { private String pipe;? public Coconut(String pipe){ this.pipe = pipe; }? // ??????? String drinkCoconutJuice(){ System.out.println("????"); return pipe; } } // ????????????? Coconut coconut = new Coconut("????"); coconut.drinkCoconutJuice(); }? /** * ????????????????????? * ?????????????????????????? */ // Coconut coconut = new Coconut("????"); // coconut.drinkCoconutJuice(); }? public static void main(String[] args) { Parcel6 p6 = new Parcel6(); p6.eatCoconut(true); }}??? ????
?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
•???????????
???????????????????????return ??????????????????????????????????????????????
public interface Contents {? int getValue();}?public class Parcel7 {? private Contents contents(){ return new Contents() {? private int value = 11;? @Override public int getValue() { return value; } }; }? public static void main(String[] args) { Parcel7 p7 = new Parcel7(); System.out.println(p7.contents().getValue()); }}?? : 11
??????????????????? {}????????? ????????????????????????????????????????????????new Contents()??????Contents???????????????????????????????????????
public class Parcel7b {? private class MyContents implements Contents {? private int value = 11;? @Override public int getValue() { return 11; } }? public Contents contents(){ return new MyContents(); }? public static void main(String[] args) { Parcel7b parcel7b = new Parcel7b(); System.out.println(parcel7b.contents().getValue()); }}?????????????? ??????????? 10.3 ?????????????
•??????????????????
????????????????(???????)????????
public class WithArgsConstructor {? private int sum;? public WithArgsConstructor(int sum){ this.sum = sum; }? public int sumAll(){ return sum; }}?public class Parcel8 {? private WithArgsConstructor withArgsConstructor(int x){? // ??WithArgsConstructor??????????????? return new WithArgsConstructor(x){? // ??sumAll???????????? @Override public int sumAll(){ return super.sumAll() * 2; } }; }? public static void main(String[] args) { Parcel8 p8 = new Parcel8(); System.out.println(p8.withArgsConstructor(10).sumAll()); }}??WithArgsConstructor ????????????sum?????????????sumAll????sum???Parcel8??withArgsConstructor??????x???????????????????????????????????????sumAll?????????????? Java????198??? ????“;”?????????????????????????????????????????
•????????????????
???????????????????????????????????????????????????????? ????????
public class Parcel9 {? private Destination destination(String dest){ return new Destination() {? // ??????? private String label = dest;? @Override public String readLabel() { return label; } }; }? public static void main(String[] args) { Parcel9 p9 = new Parcel9(); System.out.println(p9.destination("pen").readLabel()); }}????????????????????final??????final????????????????????????final?????????? ???????private???????private ??public,????????
???????????????????????Java????????????????????????????????????????????????
•??????????????????
public abstract class Base {? public Base(int i){ System.out.println("Base Constructor = " + i); }? abstract void f();}?public class AnonymousConstructor {? private static Base getBase(int i){? return new Base(i){ { System.out.println("Base Initialization" + i); }? public void f(){ System.out.println("AnonymousConstructor.f()??????"); } }; }? public static void main(String[] args) { Base base = getBase(57); base.f(); }}??? Base Constructor = 57 Base Initialization 57 AnonymousConstructor.f()??????
????? “??????????????????” ?????????????????????????
10.5 ???
10.4 ?????6???????????????????10.1 ?????????contents()?????????????????
??????????????????????????????static??????????????????????????????????????????????????????????????????????????????? ????????? ?1?????????????????????? ?2??????????????????????
???? 10.5-1
public class Parcel10 {? private int value = 11;? static int bValue = 12;? // ????? private static class PContents implements Contents {? // ??????????PContents????value??? @Override public int getValue() { return value; }? // ???????????PContents????????bValue public int f(){ return bValue; } }? // ????? private class PDestination implements Destination {? @Override public String readLabel() { return "label"; } }? // ????????????????????? public static Contents contents(){ return new PContents(); }? // ????????????????????? public Contents contents2(){ Parcel10 p10 = new Parcel10(); return p10.new PContents(); }? // ???????????????????? public static Destination destination(){ Parcel10 p10 = new Parcel10(); return p10.new PDestination(); }? // ????????????????????? public Destination destination2(){ return new PDestination(); }}??????????10.1???????? ???????????????????????????????????????
??????
??????????????????????????????? ????????????????????????????????????????????????public?static??????static????????????????????????????????????????????????????????????
public interface InnerInterface {? void f();? class InnerClass implements InnerInterface {? @Override public void f() { System.out.println("????????"); }? public static void main(String[] args) { new InnerClass().f(); } }? // ????????main??????????????????// public static void main(String[] args) {}}
??? ????????
?????????
?Java???????????????????????????????????????????????????????????????????????????????”????”??????extends???????????????????????????
??chenssy??? http://www.cnblogs.com/chenssy/p/3389027.html ?????????
public class Food {? private class InnerFruit implements Fruit{ void meakFruit(){ System.out.println("?????"); } }? private class InnerMeat implements Meat{ void makeMeat(){ System.out.println("????"); } }? public Fruit fruit(){ return new InnerFruit(); }? public Meat meat(){ return new InnerMeat(); }? public static void main(String[] args) { Food food = new Food(); InnerFruit innerFruit = (InnerFruit)food.fruit(); innerFruit.meakFruit(); InnerMeat innerMeat = (InnerMeat) food.meat(); innerMeat.makeMeat(); }}??? ????? ????
10.6 ??????
?????????????????????????????????
public class BaseClass {? class BaseInnerClass {? public void f(){ System.out.println("BaseInnerClass.f()"); } }? private void g(){ System.out.println("BaseClass.g()"); }}/** * ?????InheritInner????????BaseInnerClass??????? * ???????????????? * ??????enclosingClassReference.super()?????? * ?????????????????????? * */public class InheritInner extends BaseClass.BaseInnerClass{? // ????// public InheritInner(){}? public InheritInner(BaseClass bc){ bc.super(); }? @Override public void f() { System.out.println("InheritInner.f()"); }? /* * ??@Override ??????BaseInnerClass ???g()?? * ?????????????Override????????????? * ??????????????????g()????????? @Override public void g(){ System.out.println("InheritInner.g()"); }*/? public static void main(String[] args) { BaseClass baseClass = new BaseClass(); InheritInner inheritInner = new InheritInner(baseClass); inheritInner.f(); }}???InheritInner.f()
10.7 ??????
????????????????
public class Man {? private ManWithKnowledge man;? protected class ManWithKnowledge {? public void haveKnowledge(){ System.out.println("??????????"); } }? // ??????????haveKnowledge()?? public Man(){ System.out.println("??????????????????????????????"); new ManWithKnowledge().haveKnowledge(); }}?// ??public class InternetCelebrity extends Man {? protected class ManWithKnowledge {? public void haveKnowledge(){ System.out.println("????????????"); } }? public static void main(String[] args) { new InternetCelebrity(); }}????????????????????????????????? ??????????
??????????????????????? InternetCelebrity.haveKnowledge() ,???????????????ManWithKnowledge.haveKnowledge()??? ????????????????????????????????????????????????????????
10.8 ???????????
???????????.class ?????????????????? ?????????????.class ?? ?????: OneClass$OneInnerClass
??: ?????Java????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????get???????????????????????
10.9 ??????
1????????????????????????????????????
2?????????????????????????????????????????
3???????????????????
Java ?????????????? Java ?????????????????????? Java ????????????????????????????????????????????
??????????????????“???”??????? Java ????/???????
