在Java应用程序中找不到符号

时间：2014-07-29 00:47:20

标签： java

我正在研究一个简单的基于文本的rpg battler程序作为Java的介绍。我似乎对大多数代码有了不错的理解，但我遇到了几个问题。

我遇到的问题是在Project类中。

在我的switch语句中，我尝试使用setSpells（）和setArrows（）方法，我收到“找不到符号”错误消息。我意识到这可能是由于我在子类中设置错误，但我不确定那是什么。

第二个问题是在print语句中使用c.getName（）来拉取字符名称。该语句的c部分给出了相同的错误消息。

在这些情况下，我是否有一些简单的误解？任何帮助解决这个问题将不胜感激。谢谢。

这是我的主要项目类文件：

package project;

import java.util.Scanner;

public class Project {

public static void main(String[] args) {
    System.out.println("Welcome to Lands of the Sun\n");

    Scanner sc = new Scanner(System.in);
    String choice = "y";
    while (choice.equalsIgnoreCase("y"))
    {
        System.out.print("Please choose your class (wizard or elf): \n");
        String classChoice = sc.next();
        sc.nextLine();

        System.out.print("Please choose a name for your " + classChoice + ": ");
        String charName = sc.next();
        sc.nextLine();

        int healthVal = (int) (Math.random() * 10) + 1;

        switch (classChoice) {
            case "wizard":
                {
                    Character c = new Wizard();
                    c.setName(charName);
                    c.setGold(25);
                    c.setHealth(healthVal);
                    c.setSpells(10);
                    break;
                }
            case "elf":
                {
                    Character c = new Elf();
                    c.setName(charName);
                    c.setGold(25);
                    c.setHealth(healthVal);
                    c.setArrows(10);
                    break;
                }
        }

        System.out.print(c.getName());

        System.out.print("Continue? (y/n): ");
        choice = sc.nextLine();
        System.out.println();
    }
}

}

这是我的角色类：

package project;

public abstract class Character {
private String name;
private int gold;
private int health;
public static int count = 0;

public Character()
{
    name = "";
    gold = 0;
    health = 0;
}

public Character(String name, int gold, int health) {
    this.name = name;
    this.gold = gold;
    this.health = health;
}

public void setName(String name)
{
    this.name = name;
}

public String getName(){
    return name;
}

public void setGold(int gold)
{
    this.gold = gold;
}

public int getGold()
{
    return gold;
}

public void setHealth(int health)
{
    this.health = health;
}

public int getHealth()
{
    return health;
}
@Override
public String toString()
{
    return "Name: " + name + "\n" +
           "Gold: " + gold + "\n" +
           "Health: " + health + "\n";
}

public static int getCount()
{
    return count;
}

public abstract String getDisplayText();
}

这是我的向导子类：

package project;

public class Wizard extends Character {
private int spells;

public Wizard()
{
    super();
    spells= 0;
    count++;
}

public void setSpells(int spells)
{
    this.spells= spells;
}

public int getSpells(){
    return spells;
}

    @Override
public String getDisplayText()
{
    return super.toString() +
        "Spells: " + spells+ "\n";
}
}

最后是我的精灵子课：

package project;

public class Elf extends Character{
private int arrows;

public Elf()
{
    super();
    arrows = 0;
    count++;
}

public void setArrows(int arrows)
{
    this.arrows = arrows;
}

public int getArrows(){
    return arrows;
}

    @Override
public String getDisplayText()
{
    return super.toString() +
        "Arrows: " + arrows + "\n";
}
}

4 个答案:

答案 0 :(得分：3)

当您创建一个Characters ...

时 
Character c = new Elf();

您正在将实例向下转换为＆＃34; act＆＃34;与Character类似，这在面向对象编程中非常有用，但在这种情况下会导致问题，因为Character没有您正在寻找的方法。

相反，首先将类分配给实例的具体版本...... 

Elf elf = new Elf();

应用您需要的属性，然后将其分配给Character引用... 

Character c = null;
//...
switch (classChoice) {
    //...
    case "elf":
    {
        Elf elf = new Elf();
        //...
        c = elf;
    }
}
c = elf;

例如......

有关详细信息，请查看Polymorphism部分

答案 1 :(得分：1)

你的问题是这些行

Character c = new Wizard();
....
Character c = new Elf();

字符类本身没有setFireballs或SetArrows方法。您需要将对象定义为向导或精灵才能访问所述方法...... EG：

Elf c = new Elf();
Wizard c = new Wizard();
etc

答案 2 :(得分：0)

字符c =新向导（）; Character既没有setFireBalls方法也没有setArrows方法。

答案 3 :(得分：0)

我对您的代码进行了一些更改.. 这是最终的代码。

  

包h;

import java.util.Scanner;

公共课他{

public static void main(String[] args) {
    System.out.println("Welcome to Lands of the Sun\n");
    Character c = new Wizard();
    Character e = new Elf();
    Scanner sc = new Scanner(System.in);
    String choice = "y";
    while (choice.equalsIgnoreCase("y"))
    {
        System.out.print("Please choose your class (wizard or elf): \n");
        String classChoice = sc.next();
        sc.nextLine();

        System.out.print("Please choose a name for your " + classChoice + ": ");
        String charName = sc.next();
        sc.nextLine();

        int healthVal = (int) (Math.random() * 10) + 1;

        switch (classChoice) {
            case "wizard":
                {

                    c.setName(charName);
                    c.setGold(25);
                    c.setHealth(healthVal);
                    c.setFireballs(10);
                    break;
                }
            case "elf":
                {
                    ;
                    e.setName(charName);
                    e.setGold(25);
                    e.setHealth(healthVal);
                    e.setArrows(10);
                    break;
                }
        }

        System.out.print(c.getName());

        System.out.print("Continue? (y/n): ");
        choice = sc.nextLine();
        System.out.println();
    }
}

}

向导类

  

公共类向导扩展了角色{       private int fireballs; 

public Wizard()
{
    super();
    fireballs = 0;
    count++;
}

public void setFireballs(int fireballs)
{
    this.fireballs = fireballs;
}

public int getFireballs(){
    return fireballs;
}

    @Override
public String getDisplayText()
{
    return super.toString() +
        "Fireballs: " + fireballs + "\n";
}

    @Override
    public void setArrows(int i) {

    }

}

精灵班

  

public class Elf extends Character {       private int arrows; 

public Elf()
{
    super();
    arrows = 0;
    count++;
}

public void setArrows(int arrows)
{
    this.arrows = arrows;
}

public int getArrows(){
    return arrows;
}

    @Override
public String getDisplayText()
{
    return super.toString() +
        "Arrows: " + arrows + "\n";
}

    @Override
    public void setFireballs(int i){

    }

}

抽象类角色

  

公共抽象类Character {       私有字符串名称;       私人金;       私人健康;       public static int count = 0; 

public Character() {
    name = "";
    gold = 0;
    health = 0;
}

public Character(String name, int gold, int health) {
    this.name = name;
    this.gold = gold;
    this.health = health;
}

public void setName(String name) {
    this.name = name;
}

public String getName() {
    return name;
}

public void setGold(int gold) {
    this.gold = gold;
}

public void setHealth(int health) {
    this.health = health;
}

public int getHealth() {
    return health;
}

@Override
public String toString() {
    return "Name: " + name + "\n" + "Gold: " + gold + "\n" + "Health: "
            + health + "\n";
}

public static int getCount() {
    return count;
}

public abstract String getDisplayText();

public abstract void setFireballs(int i);

public abstract void setArrows(int i);

}

希望这会有所帮助...

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