Java：类在包中找不到彼此（工厂设计模式）

I have three different classes:

我有三个不同的类:

Woman.java

package human;
public class Woman extends Human{
    private final String pnr;
    private final String namn;

    public Woman(String n, String p){
        namn = n;
        pnr = p;
    }
    public String toString(){
        return "My name is "+namn+" and I am a woman.";
    }

}

Man.java

package human;
public class Man extends Human{
    private final String pnr;
    private final String namn;

    public Man(String n, String p){
        namn = n;
        pnr = p;
    }
    public String toString(){
        return "My name is "+namn+" and I am a man.";
    }   
}

Human.java

package human;
public abstract class Human{
    public static Human create(String namn, String pnr){
        char nastsist_char = pnr.charAt(9); // takes second last char in pnr
        String nastsist_string = Character.toString(nastsist_char);
        float siffra = Float.parseFloat(nastsist_string);   //Converts to float
        if ((siffra % 2) == 0){                 //Checks if even
            return new Man(namn, pnr);          
        }
        else{
            return new Woman(namn, pnr);
        }
    }
}

When I try to compile the file Human.java, I get the error

当我尝试编译Human.java文件时,我收到错误

cannot find symbol: class Man,

找不到符号:类男,

and

cannot find symbol: class Woman.

找不到符号:班女。

When I try to compile the file Man.java or Woman.java, I get the error

当我尝试编译Man.java或Woman.java文件时,我收到错误

cannot find symbol: class Human.

找不到符号:类人类。

No changing of public/private visibility of the classes have helped. All the files are located in a directory called human.

没有改变类的公共/私人可见性有帮助。所有文件都位于名为human的目录中。

What is the problem here?

这里有什么问题?

I should add that the goal I'm trying to achieve is to have an abstract class Human that can not be instantiated, and in that class I want to have a create method that returns instances of either Man or Woman depending on pnr. Also, I do not want Man or Woman to be possible to instantiate in any other way than through the create method.

我应该补充一点,我想要实现的目标是拥有一个无法实例化的抽象类Human,并且在该类中我想要一个create方法,根据pnr返回Man或Woman的实例。此外,我不希望男人或女人可以通过create方法以任何其他方式实例化。

Thanks

4 个解决方案

#1

There's no problem with your code or packaging, so the problem is elsewhere. How do you compile? I'm guessing you might be doing

您的代码或包装没有问题,因此问题出在其他地方。你怎么编译?我猜你可能会这样做

javac human/Human.java

which will not work, since Man and Woman is then not on the classpath and thus not known to the Java compiler when working on Human. You should include these when compiling:

这是行不通的,因为男人和女人不在类路径上,因此在处理Human时Java编译器不知道。编译时应包括以下内容:

javac human/*.java

Cheers,

#2

Do you compile them by yourself, in a terminal or something? Try to compile all files all together then:

你自己编译,在终端或其他东西?尝试一起编译所有文件然后:

javac Man.java Woman.java Human.java

#3

You have cycles in the classes. So you have two choices. 1) Compile all together 2) Create a new class e.g. Factory and instantiate the objects there

你在课堂上有周期。所以你有两个选择。 1)一起编译2)创建一个新类,例如工厂并在那里实例化对象

It's never a good idea to create cycles in you code

在代码中创建循环永远不是一个好主意

#4

Have you tried : javac *.java in your folder ?

你试过:你的文件夹中有javac * .java吗?

Java: How can I compile an entire directory structure of code ?

Java:如何编译整个代码目录结构?

#1