java编程思想第四版第九章习题

第三题

package net.mindview.interfaces;
abstract class Base{
    public Base(){
        print();
    }
    abstract void print();
}
public class Test3 extends Base{
    private int i = 5;
    @Override
    void print() {
        System.out.println(i);
    }
    public static void main(String[] args) {
        Test3 t = new Test3();
        t.print();
    }
}

输出结果:

0
5

调用基类构造方法的时候, 只是给子类的成员变量分配了一块内存空间, 并将内存空间的值设置为默认值0. 当真正调用子类构造方法之前才会为成员变量赋值.

第七题

package net.mindview.interfaces;

//啮(nie四声)齿动物
interface Rodent{
  void say();
}

//老鼠
class Mouse implements Rodent{
  public void say(){System.out.println("hi,我是 Mouse");}
}

//鼹鼠
class Gerbil implements Rodent{
  public void say(){System.out.println("hi,我是 Gerbil");}
}

//大颊鼠
class Hamster implements Rodent{
  public void say(){System.out.println("hi,我是 Hamster");}
}
public class RodentHome {
    public static void instroduce(Rodent rodent){
        rodent.say();
    }
    
    public static void instroduceAll(Rodent[] rodents){
        for(Rodent r: rodents){
            instroduce(r);
        }
    }
    public static void main(String[] args) {
        Rodent[] rodents = {
                new Mouse(),
                new Gerbil(),
                new Hamster()
        };
        instroduceAll(rodents);
    }

}

第八题

package net.mindview.interfaces;

import java.util.Random;


/** 定义一个乐器类 */
interface Instrucment {
    int value = 5; //定义在接口中的成员是static&final的
    void play(Note n);
    void adjust();
}

/**抽象类*/
abstract class PublicMethod implements Instrucment{
    public abstract void play(Note n);
    //这个方法不用谢,以为继承自Object的类都有toString()方法
    //public abstract String toString();
    public abstract void adjust();
}

/**定义n个子类*/
class Wind extends PublicMethod {
    public void play(Note n){ System.out.println("Wind.play() " + n);}
    
    public String toString(){ return "Wind.what()";}
    
    public void adjust(){ System.out.println("Wind.adjust()");}
}

class Purcussion extends PublicMethod{
    public void play(Note n){ System.out.println("Purcussion.play() " + n);}
    
    public String toString(){ return "Purcussion.what()";}
    
    public void adjust(){ System.out.println("Purcussion.adjust()");}
}

class Stringed extends PublicMethod{
    public void play(Note n){ System.out.println("Stringed.play() " + n);}
    
    public String toString(){ return "Stringed.what()";}
    
    public void adjust(){ System.out.println("Stringed.adjust()");}
}

class Brass extends Wind{
    public void play(Note n){ System.out.println("Brass.play() " + n);}
    
    public void adjust(){ System.out.println("Brass.adjust()");}
}

class WoodWind extends Wind{
    public void play(Note n){ System.out.println("WoodWind.play() " + n);}
    
    public String toString(){ return "WoodWind.what()";}
}

class Other extends Wind{
    public void play(Note n){ System.out.println("Other.play() " + n);}
    
    public String toString(){ return "Other.what()";}
}

/** 定义一个随机乐器生成器 */
class RandomInstrucmentGenerator {
    Random rand = new Random(100);
    public Instrucment next(){
        switch(rand.nextInt(6)){
            default:
            case 0: return new Wind();
            case 1: return new Purcussion();
            case 2: return new Stringed();
            case 3: return new Brass();
            case 4: return new WoodWind();
            case 5: return new Other();
            
        }
    }
}

public class Music5 {

    public static void tune(Instrucment i){
        i.play(Note.MIDDLE_C);
        i.toString();
    }
    
    public static void tuneAll(Instrucment[] e){
        for(Instrucment i : e){
            tune(i);
        }
    }
    
    private static RandomInstrucmentGenerator gen = new RandomInstrucmentGenerator();
    public static void main(String[] args) {
        
        
        /*Instrucment[] orchestra = {
            new Wind(),
            new Purcussion(),
            new Stringed(),
            new Brass(),
            new WoodWind(),
            new Other()
        };*/
        Instrucment[] ins = new Instrucment[10];
        for(int i=0; i<ins.length; i++){
            ins[i] = Music5.gen.next();
        }
        
        tuneAll(ins);
    }
}

练习11--这个练习是巩固如何写适配器设计模式

package net.mindview.interfaces;

/**
 * 字符串反转类
 */
public class StringReverse {
    public String name(){
        return getClass().getSimpleName();
    }
    //反转
    public String reverse(String s) {
        char[] array = s.toCharArray();
        String reverse = "";
        for (int i = array.length - 1; i >= 0; i--) {
            reverse += array[i];
        }
        return reverse;
    }
}

package net.mindview.interfaces;

public class StringReverseAdapter implements Processor{
    StringReverse stringReverse;
    public StringReverseAdapter(StringReverse stringReverse){
        this.stringReverse = stringReverse;
    }
    @Override
    public String name() {
        // TODO Auto-generated method stub
        return stringReverse.name();
    }

    @Override
    public Object process(Object input) {
        // TODO Auto-generated method stub
        return stringReverse.reverse((String)input);
    }
}

在使用的时候,可以直接调用Apply的process方法

public static void main(String[] args) {
        Apply.process(new StringReverseAdapter(new StringReverse()), "i am lily");
    }

Apply方法没有写出来,这个类实在课文内部定义的,可以参考http://www.cnblogs.com/ITPower/p/8550627.html中第二点:解耦的案例一,案例二和案例三. 其中Apply类定义在案例一中。

第十二题

package net.mindview.interfaces;


interface CanFight {
    void fight();
}

interface CanSwim {
    void swim();
}

interface CanFly {
    void fly();
}

interface CanClimb {
    void climb();
}

//行为特征
class ActionCharacter {
    public void fight(){ }
}

class Hero extends ActionCharacter implements CanFight,CanSwim,CanFly,CanClimb{
    @Override
    public void fly() { }
    
    @Override
    public void swim() { }

    @Override
    public void climb() { }
} 


//冒险
public class Adventure {
    public static void f(CanFly fly){
        fly.fly();
    }
    public static void s(CanSwim swim){
        swim.swim();
    }
    public static void v(CanFight fight){
        fight.fight();
    }
    public static void m(ActionCharacter ac){
        ac.fight();
    }
    public static void p(CanClimb c){
        c.climb();
    }
    public static void main(String[] args) {
        Hero hero = new Hero();
        f(hero);
        s(hero);
        v(hero);
        m(hero);
        p(hero);

    }

}

第十四题：这道题的思想和书上p180页的案例思想一样.继承+多次实现接口

package net.mindview.interfaces;

interface BaseInterface1 {
    public void a();
    public void b();
}

interface BaseInterface2 {
    public void c();
    public void d();
}

interface BaseInterface3 {
    public void e();
    public void f();
}

interface Interface4 extends BaseInterface1,BaseInterface2,BaseInterface3{
    public void g();
    
}

class Specific implements Interface4{
    public void h(){ }

    @Override
    public void a() { }

    @Override
    public void b() { }

    @Override
    public void c() { }

    @Override
    public void d() { }

    @Override
    public void e() { }

    @Override
    public void f() { }

    @Override
    public void g() { }
}


public class Test14 extends Specific implements Interface4{
    public static void aa(BaseInterface1 b1){
        b1.a();
        b1.b();
    }
    
    public static void bb(BaseInterface2 b){
        b.c();
        b.d();
    }
    
    public static void cc(BaseInterface3 b){
        b.e();
        b.f();
    }
    
    public static void dd(Interface4 b){
        b.g();
    }
    public static void main(String[] args) {
        Specific specific = new Specific();
        aa(specific);
        bb(specific);
        cc(specific);
        dd(specific);
    }
}

第十六题

package net.mindview.interfaces;

import java.io.IOException;
import java.nio.CharBuffer;
import java.util.Random;
import java.util.Scanner;

class RandomChar {
    Random rand = new Random(47);
    Random count = new Random(47);
    private static final char[] captials = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray(); 
    public char[] make(){
        StringBuffer sb = new StringBuffer("");
        for(int i=0; i<count.nextInt(10); i++){
            sb.append(captials[rand.nextInt(captials.length)]);
        }
        return sb.toString().toCharArray();
    }
    
    public static void main(String[] args) {
        RandomChar rc = new RandomChar();
        char[] c = rc.make();
        System.out.println(c);
        
        for(char ch:c){
            System.out.print(ch);
        }
    }
}

public class AdapterRandomChar implements Readable{
    RandomChar rc;
    private int count;
    public AdapterRandomChar(RandomChar rc, int count){
        this.rc = rc;
        this.count = count;
    }
    @Override
    public int read(CharBuffer cb) throws IOException {
        if(count-- == 0){
            return -1;
        }
        StringBuffer sb = new StringBuffer("");
        for(char c:rc.make()){
            sb.append(c);
        }
        String result = sb.toString() + " " ;
        cb.append(result);
        return result.length();
    }

    public static void main(String[] args) {
        Scanner s = new Scanner(new AdapterRandomChar(new RandomChar(), 5));
        while(s.hasNext()){
            System.out.print(s.next()+" ");
        }
    }
}

第十八题

package net.mindview.interfaces;
//产品
interface Cycle {
}

class Unicycle implements Cycle{
    public Unicycle(){
        System.out.println("我是一个Unicycle");
    }
}

class Bicycle implements Cycle{
    public Bicycle(){
        System.out.println("我是一个Bicycle");
    }
}

class Tricycle implements Cycle{
    public Tricycle(){
        System.out.println("我是一个Tricycle");
    }
}

//工厂类
interface CycleFactory{
    public Cycle make();
}

class UnicycleFactory implements CycleFactory{
    @Override
    public Cycle make() {
        return new Unicycle();
    }
    
}

class BicycleFactory implements CycleFactory{
    @Override
    public Cycle make() {
        return new Bicycle();
    }
    
}

class TricycleFactory implements CycleFactory{
    @Override
    public Cycle make() {
        return new Tricycle();
    }
    
}


public class CycleCustomer {
    public static Cycle serviceCustoemr(CycleFactory fact){
        return fact.make();
    }
    public static void main(String[] args) {
        Cycle u = serviceCustoemr(new UnicycleFactory());
        Cycle b = serviceCustoemr(new BicycleFactory());
        Cycle t = serviceCustoemr(new TricycleFactory());

    }

}

第十九题

package net.mindview.interfaces;

import java.util.Random;

/**
 * 这时一个抛硬币和掷骰子等类型的框架
 */

interface ThrowProduct {}

class ThrowCorn implements ThrowProduct{
    Random rand = new Random(47);
    public ThrowCorn(){
        if(rand.nextInt(100) %2 ==0){
            System.out.println("硬币的正面");
        }else{
            System.out.println("硬币的反面");
        }
    }
}

class ThrowDice implements ThrowProduct{
    Random rand = new Random(47);
    public ThrowDice(){
        System.out.println("掷的骰子数是"+rand.nextInt(7));
    }
}

interface ThrowFactory{
    ThrowProduct throwOut();
}

class ThrowCornFactory implements ThrowFactory{
    public ThrowCornFactory(){
        System.out.print("开始抛硬币:");
    }
    @Override
    public ThrowProduct throwOut() {
        return new ThrowCorn();
    }
}

class ThrowDiceFactory implements ThrowFactory{
    public ThrowDiceFactory(){
        System.out.print("开始掷骰子:");
    }
    @Override
    public ThrowProduct throwOut() {
        return new ThrowDice();
    }
}


public class ThrowFrame {
    public static ThrowProduct service(ThrowFactory f){
        return f.throwOut();
    }
    public static void main(String[] args) {
        service(new ThrowCornFactory());
        service(new ThrowDiceFactory());

    }

}

结果:

开始抛硬币:硬币的正面
开始掷骰子:掷的骰子数是6

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原文地址：https://www.cnblogs.com/ITPower/p/8535281.html