创建对象时如何解决“错误：找不到符号”？答案

【问题标题】：How to fix "Error: Cannot find symbol" when creating an object?创建对象时如何解决“错误：找不到符号”？
【发布时间】：2019-08-17 15:07:07
【问题描述】：

我不明白我的编译器如何找不到类Weight，考虑到我不是已经在我的public boolean checkWeight 方法中实现了吗？编译器指向的行：

`Weight first = new Weight();`

和

`Weight second = new Weight();`

public class Guard {

    int stashWeight;

    public Guard ( int maxWeight ) {
        this.stashWeight = maxWeight;
    }

    public boolean checkWeight (Weight maxWeight) {
        if ( maxWeight.weight >= stashWeight ) {
            return true;
        } else {
            return false;
        }
    }

    public static void main (String[] args ) {
        Weight first = new Weight();
        first.weight = 3000;
        Weight second = new Weight();
        second.weight = 120;

        Guard grams = new Guard(450);
        System.out.println("Officer, can I come in?");
        boolean canFirstManGo = grams.checkWeight(first);
        System.out.println(canFirstManGo);

        System.out.println();

        System.out.println("Officer, how about me?");
        boolean canSecondManGo = grams.checkWeight(second);
        System.out.println(canSecondManGo);

    }
}

【问题讨论】：

你导入正确的Weight类了吗？
你的体重等级在哪里
我可能已经昏迷了。出于某种未知的原因，我的新手头脑认为我已经做了我的体重等级：public boolean checkWeight (maxWeight Weight)。感谢大家的提醒

标签： java class inheritance methods

【解决方案1】：

您应该像这样定义Weight 类：

public class Weight {

    public int weight;

    public int getWeight() {
        return weight;
    }

    public void setWeight(int weight) {
        this.weight = weight;
    }
}

输出：

Officer, can I come in?
true

Officer, how about me?
false

或使用 import 关键字导入您的 Weight 类。

【讨论】：

【解决方案2】：

您的代码中缺少您的 Weight 类请参见下面的代码

class Weight {

    public int weight;

    public int getWeight() {
        return weight;
    }

    public void setWeight(int weight) {
        this.weight = weight;
    }
}

public class Guard {

    int stashWeight;

    public Guard(int maxWeight) {
        this.stashWeight = maxWeight;
    }

    public boolean checkWeight(Weight maxWeight) {
        if (maxWeight.weight >= stashWeight) {
            return true;
        } else {
            return false;
        }
    }

    public static void main(String[] args) {
        Weight first = new Weight();
        first.weight = 3000;
        Weight second = new Weight();
        second.weight = 120;

        Guard grams = new Guard(450);
        System.out.println("Officer, can I come in?");
        boolean canFirstManGo = grams.checkWeight(first);
        System.out.println(canFirstManGo);

        System.out.println();

        System.out.println("Officer, how about me?");
        boolean canSecondManGo = grams.checkWeight(second);
        System.out.println(canSecondManGo);

    }
}

输出

Officer, can I come in?
true
Officer, how about me?
false

【讨论】：

【解决方案3】：

您的体重等级是否在不同的包装中？ Weight 类的访问修饰符是什么？

请在上面验证并查看下面的文档。

Access Modifiers

【讨论】：

【解决方案4】：

方法参数“maxWeight”的类型为“Weight”，Java 无法找到其定义来解决您的程序依赖关系。无法通过类路径找到类将导致错误“找不到符号”。您可能想要定义“重量”类并将其导入，就像其他人回复您一样。
您真的需要“重量”类吗？您只是将传递的参数与“Guard”的 stashWeight 进行比较。

您的公共方法可能只是：

public boolean checkWeight(int maxWeight) {
        return maxWeight >= stashWeight;

}

主要方法可以更新为：

public static void main(String[] args) {
    int firstWeight = 3000;
    int secondWeight = 120;

    Guard grams = new Guard(450);
    System.out.println("Officer, can I come in?");
    boolean canFirstManGo = grams.checkWeight(firstWeight);
    System.out.println(canFirstManGo);

    System.out.println();

    System.out.println("Officer, how about me?");
    boolean canSecondManGo = grams.checkWeight(secondWeight);
    System.out.println(canSecondManGo);

}

【讨论】：