1
/**
* 惰性初始化
* <p/>
* Created by wang on 15/8/6.
*/
class Init {
public Init() {
System.out.println("Init init");
}
}
public class LazyInit {
Init init;
@Override
public String toString() {
System.out.println("Print");
init = new Init();
return super.toString();
}
public static void main(String[] arg) {
System.out.println(new LazyInit());
}
}
/**
* Output:
Print
Init init
[email protected]
*/2
/**
* 继承
* <p/>
* Created by wang on 15/8/7.
*/
class Cleaner {
private String s = "Cleaner";
public static void main(String[] args) {
Cleaner x = new Cleaner();
x.dilute().apply().scrub();
System.out.println(x);
}
public void append(String a) {
s += a;
}
public Cleaner dilute() {
append(" dilute");
return this;
}
public Cleaner apply() {
append(" apply");
return this;
}
public Cleaner scrub() {
append(" scrub");
return this;
}
@Override
public String toString() {
return s;
}
}
class Detergent extends Cleaner {
public static void main(String[] args) {
Detergent d = new Detergent();
((Detergent) d.dilute().apply()).scrub().foam();
System.out.println(d);
}
@Override
public Detergent scrub() {
append(" Detergent: scrub()");
super.scrub();
return this;
}
public Detergent foam() {
append(" foam");
return this;
}
}
public class Disinfectant extends Detergent {
public static void main(String[] args) {
Disinfectant d = new Disinfectant();
((Disinfectant) d.dilute().apply()).scrub().sterilize();
System.out.println(d);
Detergent.main(args);
Cleaner.main(args);
}
@Override
public Disinfectant scrub() {
append(" Disinfectant: scrub()");
super.scrub();
return this;
}
public Disinfectant sterilize() {
append(" sterilize");
return this;
}
}
/**
* Output:
Cleaner dilute apply Disinfectant: scrub() Detergent: scrub() scrub sterilize
Cleaner dilute apply Detergent: scrub() scrub foam
Cleaner dilute apply scrub
*/3
/**
* 默认构造器
* <p/>
* Created by wang on 15/8/7.
*/
class Art {
public void show() {
System.out.println("show");
}
}
class Drawing extends Art {
public void draw() {
System.out.println("draw");
}
}
public class Cartoon extends Drawing {
public void play() {
System.out.println("play");
}
public static void main(String[] args) {
Cartoon c = new Cartoon();
c.show();
c.draw();
c.play();
}
}4
/**
* 基类构造器
* <p/>
* Created by wang on 15/8/7.
*/
class Art {
public Art(String author) {
System.out.println("Art:" + author);
}
}
class Drawing extends Art {
public Drawing(String author) {
super(author);
System.out.println("Drawing:" + author);
}
}
public class Cartoon extends Drawing {
public Cartoon(String author) {
super(author);
System.out.println("Cartoon:" + author);
}
public static void main(String[] args) {
new Cartoon("Caroline");
}
}
/**
* Output:
Art:Caroline
Drawing:Caroline
Cartoon:Caroline
*/5
/**
* 构造函数先于其他函数调用.
* <p/>
* Created by wang on 15/8/7.
*/
class A {
public A() {
System.out.println("A");
}
}
class B {
public B() {
System.out.println("B");
}
}
class C extends A {
private B mB = new B();
}
public class Cross {
public static void main(String[] args) {
C c = new C();
}
}
/**
* Output:
A
B
*/6
报错: 对super的调用必须是构造函数中的第一个语句.
/**
* 带参数的构造器
* <p/>
* Created by wang on 15/8/8.
*/
class Game {
Game(int i) {
System.out.println("Game Constructor:" + i);
}
}
class BoardGame extends Game {
BoardGame(int i) {
super(i);
System.out.println("BoardGame Constructor:" + i);
}
}
public class Chess extends BoardGame {
public Chess() {
super(11);
System.out.println("Chess Constructor");
// super(11); // 报错
}
public static void main(String[] args) {
new Chess();
}
}
/**
* 报错: 对super的调用必须是构造函数中的第一个语句
*/7
/**
* 继承带参数的构造器
* <p/>
* Created by wang on 15/8/7.
*/
class A {
public A(String s) {
System.out.println("A:" + s);
}
}
class B {
public B(String s) {
System.out.println("B:" + s);
}
}
class C extends A {
public C(String s) {
super(s);
}
private B mB = new B("Caroline");
}
public class Cross {
public static void main(String[] args) {
new C("Wendy");
}
}
/**
* Output:
A:Wendy
B:Caroline
*/8
/**
* 构造器
* Created by wang on 15/8/8.
*/
class Haha {
public Haha(String s) {
System.out.println(s + ": Haha");
}
}
public class DConstructor extends Haha {
public DConstructor() {
this("Caroline");
}
public DConstructor(String s) {
super(s);
}
public static void main(String[] args) {
new DConstructor();
}
}
/**
* Output:
* Caroline: Haha
*/9
/**
* 派生类自动创建基类的成员变量
* <p/>
* Created by wang on 15/8/8.
*/
class Component1 {
public Component1() {
System.out.println("Component1");
}
}
class Component2 {
public Component2() {
System.out.println("Component2");
}
}
class Component3 {
public Component3() {
System.out.println("Component3");
}
}
class Root {
Component1 c1 = new Component1();
Component2 c2 = new Component2();
Component3 c3 = new Component3();
}
public class Stem extends Root {
public static void main(String[] args) {
new Stem();
}
}10
/**
* 派生类自动创建基类的成员变量
* <p/>
* Created by wang on 15/8/8.
*/
class Component1 {
public Component1(String s) {
System.out.println("Component1:" + s);
}
}
class Component2 {
public Component2(String s) {
System.out.println("Component2:" + s);
}
}
class Component3 {
public Component3(String s) {
System.out.println("Component3:" + s);
}
}
class Root {
Component1 c1 ;
Component2 c2 ;
Component3 c3 ;
public Root(String s1, String s2, String s3) {
c1 = new Component1(s1);
c2 = new Component2(s2);
c3 = new Component3(s3);
}
}
public class Stem extends Root {
public Stem(String s1, String s2, String s3) {
super(s1, s2, s3);
}
public static void main(String[] args) {
new Stem("Hello", "Caroline", "Wendy");
}
}
/**
* Output:
Component1:Hello
Component2:Caroline
Component3:Wendy
*/11
/**
* 继承
* <p/>
* Created by wang on 15/8/7.
*/
class Cleaner {
private String s = "Cleaner";
public static void main(String[] args) {
Cleaner x = new Cleaner();
x.dilute().apply().scrub();
System.out.println(x);
}
public void append(String a) {
s += a;
}
public Cleaner dilute() {
append(" dilute");
return this;
}
public Cleaner apply() {
append(" apply");
return this;
}
public Cleaner scrub() {
append(" scrub");
return this;
}
@Override
public String toString() {
return s;
}
}
public class Detergent {
private Cleaner c;
public Detergent() {
c = new Cleaner();
}
public static void main(String[] args) {
Detergent d = new Detergent();
d.dilute().apply().scrub();
System.out.println(d);
}
public Detergent dilute() {
c.append(" dilute");
return this;
}
public Detergent apply() {
c.append(" apply");
return this;
}
public Detergent scrub() {
c.append(" Detergent: scrub");
return this;
}
@Override
public String toString() {
return c.toString();
}
}
/**
* Output:
Cleaner dilute apply Detergent: scrub
*/12
/**
* 确保正确的清理
* <p/>
* Created by wang on 15/8/8.
*/
class Component1 {
public Component1(String s) {
System.out.println("Component1:" + s);
}
void dispose() {
System.out.println("Dispose Component1");
}
}
class Component2 {
public Component2(String s) {
System.out.println("Component2:" + s);
}
void dispose() {
System.out.println("Dispose Component2");
}
}
class Component3 {
public Component3(String s) {
System.out.println("Component3:" + s);
}
void dispose() {
System.out.println("Dispose Component3");
}
}
class Root {
Component1 c1 ;
Component2 c2 ;
Component3 c3 ;
public Root(String s1, String s2, String s3) {
c1 = new Component1(s1);
c2 = new Component2(s2);
c3 = new Component3(s3);
}
void dispose() {
c1.dispose();
c2.dispose();
c3.dispose();
System.out.println("Dispose Root");
}
}
public class Stem extends Root {
public Stem(String s1, String s2, String s3) {
super(s1, s2, s3);
}
@Override
void dispose() {
System.out.println("Dispose Stem");
super.dispose();
}
public static void main(String[] args) {
Stem s = new Stem("Hello", "Caroline", "Wendy");
s.dispose();
}
}
/**
* Output:
Component1:Hello
Component2:Caroline
Component3:Wendy
Dispose Stem
Dispose Component1
Dispose Component2
Dispose Component3
Dispose Root
*/13
/**
* 继承重载
* Created by wang on 15/8/17.
*/
class OneClass {
void sayHello(String s) {
System.out.println(s);
}
void sayHello(int i) {
System.out.println(i + "-Hello");
}
void sayHello(float f) {
System.out.println(f + "~Hello");
}
}
class Doll {
@Override
public String toString() {
return "Doll";
}
}
class TwoClass extends OneClass {
public void sayHello(Doll d) {
System.out.println(d + " say Hello");
}
}
public class OverloadClass {
public static void main(String[] args) {
TwoClass t = new TwoClass();
t.sayHello(new Doll());
t.sayHello("Caroline");
t.sayHello(2);
t.sayHello(0.5f);
}
}
/**
* Output:
Doll say Hello
Caroline
2-Hello
0.5~Hello
*/14
/**
* 使用组合处理对象
* <p/>
* Created by wang on 15/8/17.
*/
class Engine {
public void start() {
System.out.println("Start Engine");
}
public void rev() {
System.out.println("Rev Engine");
}
public void stop() {
System.out.println("Stop Engine");
}
public void service() {
System.out.println("Service Engine");
}
}
class Wheel {
public void inflate(int psi) {
System.out.println("Wheel psi-" + psi);
}
}
class Window {
public void rollUp() {
System.out.println("Window roll up");
}
public void rollDown() {
System.out.println("Window roll down");
}
}
class Door {
public Window window = new Window();
public void open() {
System.out.println("Window open");
}
public void close() {
System.out.println("Window close");
}
}
public class Car {
public Engine engine = new Engine();
public Wheel[] mWheels = new Wheel[4];
public Door left = new Door(), right = new Door();
{
for (int i = 0; i < mWheels.length; ++i) {
mWheels[i] = new Wheel();
}
}
public static void main(String[] args) {
Car c = new Car();
c.engine.start();
c.engine.rev();
c.engine.service();
c.engine.stop();
c.mWheels[1].inflate(20);
c.mWheels[3].inflate(25);
c.left.window.rollUp();
c.right.open();
}
}
/**
* Output:
Start Engine
Rev Engine
Service Engine
Stop Engine
Wheel psi-20
Wheel psi-25
Window roll up
Window open
*/15
package access.local;
/**
* protected方法类
* Created by wang on 15/8/17.
*/
public class BabaoClass {
protected void drink() {
System.out.println("Babao Drink");
}
}package access.local;
/**
* protected提供包内访问权限
* Created by wang on 15/8/17.
*/
public class DrinkBabao {
public static void main(String[] args) {
BabaoClass b = new BabaoClass();
b.drink(); // protected提供包内访问权限
}
}
/**
* Output:
* Babao Drink
*/package access.foreign;
import access.local.BabaoClass;
/**
* 包外访问继承Protected
* Created by wang on 15/8/17.
*/
public class LotusBabaoClass extends BabaoClass {
public static void main(String[] args) {
LotusBabaoClass l = new LotusBabaoClass();
l.drink();
}
@Override
protected void drink() {
System.out.print("Lotus ");
super.drink();
}
}
/**
* Output:
Lotus Babao Drink
*/16&17
/**
* 向上转型
* Created by wang on 15/8/18.
*/
class Amphibian {
public void crawl(){
System.out.println("Amphibian Crawl");
}
protected void color() {
System.out.println("Amphibian Gray");
}
}
class Frog extends Amphibian {
@Override
protected void color() {
System.out.println("Frog Green");
}
}
public class UpCastClass {
static public void show(Amphibian a) {
a.crawl();
a.color();
}
public static void main(String[] args) {
Frog frog = new Frog();
show(frog);
}
}
/**
* Output:
Amphibian Crawl
Frog Green
*/
18
/**
* final和static final
* <p/>
* Created by wang on 15/8/18.
*/
class Value {
public int i;
public Value(int i) {
this.i = i;
}
@Override
public String toString() {
return i + "";
}
}
class Corn {
public static final Value SV = new Value(22);
public final Value fv = new Value(11);
}
public class FinalTest {
public static void main(String[] args) {
Corn c1 = new Corn();
Corn c2 = new Corn();
// c1.fv = new Value(12); // 静态变量不变
System.out.println(c1.SV.i = 20);
System.out.println(c1.fv.i = 10);
// 静态变量类共享
System.out.println(c1.SV);
System.out.println(c2.fv);
}
}
/**
* Output:
20
10
20
11
*/19
/**
* 空白final
* <p/>
* Created by wang on 15/8/18.
*/
public class EmptyFinal {
public final int i;
public EmptyFinal() {
i = 12;
}
public EmptyFinal(int i) {
this.i = i;
}
public static void main(String[] args) {
EmptyFinal ef1 = new EmptyFinal();
System.out.println(ef1.i);
// ef.i = 10; // 无法为最终变量 i 指定值
EmptyFinal ef2 = new EmptyFinal(2);
System.out.println(ef2.i);
}
}
/**
* Output:
12
2
*/20
/**
* 重载
* <p/>
* Created by wang on 15/8/20.
*/
class HahaClass {
protected void f() {
System.out.print("HAHA");
}
}
class HeheClass extends HahaClass {
@Override
protected void f() {
super.f();
System.out.println(" and HEHE");
}
protected void f(String s) {
System.out.println(s + " say HEHE");
}
}
public class OverrideClass {
public static final void main(String[] args) {
HeheClass h = new HeheClass();
h.f();
h.f("Caroline");
}
}
/**
* Output:
HAHA and HEHE
Caroline say HEHE
*/版权声明：本文为博主原创文章，未经博主允许不得转载。
时间： 2024-10-28 16:38:36