Java 如何将枚举值传递给构造函数
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How to pass an enum value to a constructor
提问by Pavlos Panteliadis
protected enum Category { Action, Fiction, Drama, Romance, SciFi, Poems, Kids }
I have created this enumtype, and now I have to make a constructor for my class.
我已经创建了这种enum类型，现在我必须为我的类创建一个构造函数。
public Book(String title, int code, List<String> authors, String publisher, int year, Category categ){
this.title = title;
this.code = code;
this.authors = authors;
this.publisher = publisher;
this.year = year;
this.category = ....;
}
I don't understand how I will pass to the constructor the value of the enumerated type.
我不明白如何将枚举类型的值传递给构造函数。
Can anyone help?
任何人都可以帮忙吗？
I know it's beginners question, but I can't seem to find an answer anywhere.
我知道这是初学者的问题，但我似乎无法在任何地方找到答案。
采纳答案by Suresh Atta
Something like this
像这样的东西
new Book( title, ........ ,Category.anyEnumConstant);
For ex:
例如：
Book book= new Book( title, ........ ,Category.Fiction);
Then inside the constructor
然后在构造函数里面
this.category = categ;
回答by Leonard Brünings
public Book(String title, int code, List<String> authors, String publisher, int year, Category categ){
// ...
this.category = categ;
}
Then call
然后打电话
new Book(/* ... */, Category.Action)
回答by SudoRahul
You can either send the enum as such or send a String and use the valueOf() to get the Enum.
您可以发送枚举，也可以发送字符串并使用 valueOf() 获取枚举。
Solution 1:Send the enum as such.
解决方案 1：发送枚举。
new Book(title, code, authors, publisher, year, Category.Action);
and in your constructor,
在你的构造函数中，
public Book(String title, int code, List<String> authors, String publisher, int year, Category categ){
...
this.category = categ;
}
Solution 2:Send a string value and use the valueOf()to get the enum from it.
解决方案 2：发送一个字符串值并使用valueOf()从中获取枚举。
new Book(title, code, authors, publisher, year, "Action");
and in your constructor,
在你的构造函数中，
public Book(String title, int code, List<String> authors, String publisher, int year, String categString){
....
this.category = Category.valueOf(categString);
}
回答by Yogesh Verma
Here is simple assignment of enum Constant value to a enum variable.
这是将枚举常量值简单分配给枚举变量的过程。
String title= "somevalue";
int code = 1;
ArrayList<String> arrayList = new ArrayList<String>();
String publisher = "somevalue";
int year=2013;
Category categ = Category.Action;
Book book = new Book(title, code, arrayList, publisher, year, categ);
In Enums we just use the enums Object Constants declared in Enum declaration. Actually they are the objects of your enum. here is a link where you can find a simple example to explore enums. http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html
在枚举中，我们只使用枚举声明中声明的枚举对象常量。实际上，它们是您枚举的对象。这是一个链接，您可以在其中找到一个简单的示例来探索枚举。 http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html
and in Constructor declaration you just simply have to assign the value like other variables.
在构造函数声明中，您只需像其他变量一样分配值。
this.category = categ;
