从 class 创建新的 object 时出现“找不到符号”错误？

Question

public class Monster{

public final String TOMBSTONE = "Here Lies a Dead monster";


private int health = 500;
private int attack = 20;
private int movement = 2;

public String name = "Big Monster";


public int getAttack()
{
    return attack;
}

public int getMovement()
{
    return movement;
}

public int getHealth()
{
    return health;
}

public Monster(int health, int attack, int movement)
{
    this.health = health;
    this.attack = attack;
    this.movement = movement;

}

public Monster()
{

}}


public class Frank {

public static void main(String[] args){

    Monster NewMonster = new Monster();

    NewMonster.name = "Frank";

    System.out.println(NewMonster.name + " has an attack value of " + NewMonster.getAttack());

}

}

尝试从我的 Monster class 创建新的 object 时，出现此错误：

Frank.java:5: error: cannot find symbol
            Monster NewMonster = new Monster();
            ^

符号：class 怪物位置：class 弗兰克

我对 Java 很陌生，所以很抱歉，如果这是一个简单/容易的修复，但我研究的所有内容都没有给我解决这个错误的方法。

提前感谢您的任何回复/反馈。

Answer 1

Java 的一个文件中不允许有多个公共类。 因此，您需要删除其中一个类的公共修饰符，或者将主要方法放在公共 class 中。 我做了后者，因为没有必要将主要方法放在单独的 class 中来实例化您的 object。

我已经更新了你的代码，它现在可以运行了

public class Monster{

    public static void main(String[] args) {

        Monster NewMonster = new Monster();

        NewMonster.name = "Frank";

        System.out.println(NewMonster.name + " has an attack value of 
        " + NewMonster.getAttack());
    }

    public final String TOMBSTONE = "Here Lies a Dead monster";


    private int health = 500;
    private int attack = 20;
    private int movement = 2;

    public String name = "Big Monster";


    public int getAttack() {
        return attack;
    }

    public int getMovement(){
        return movement;
    }

    public int getHealth(){
        return health;
    }

    public Monster(int health, int attack, int movement){
        this.health = health;
        this.attack = attack;
        this.movement = movement;
    }

    public Monster(){}
}

Answer 2

1 您必须只定义一个 class 一个公共，它将根据您的 java 文件名（.java）保存

2 object 引用将始终为小写

class 怪物{

public final String TOMBSTONE = "Here Lies a Dead monster";

private int health = 500;
private int attack = 20;
private int movement = 2;

public String name = "Big Monster";

public int getAttack() {
    return attack;
}

public int getMovement() {
    return movement;
}

public int getHealth() {
    return health;
}

public Monster(int health, int attack, int movement) {
    this.health = health;
    this.attack = attack;
    this.movement = movement;

}

public Monster() {

}

} // 只有 Frank 可以是单个 java 文件中的公共 class，否则创建两个不同的 java 类并导入。 公共 class 弗兰克 {

公共 static 无效主（字符串 [] 参数）{

Monster newMonster = new Monster();

newMonster.name = "Frank";

System.out.println(newMonster.name + " has an attack value of " + newMonster.getAttack());

} }

Output：弗兰克的攻击值为20