如何在java中返回枚举值
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How to return enum value in java
提问by Mathew
How can I return enums like this?
我怎样才能返回这样的枚举？
Before I was returing an int with 0 if no, 1 if yes and 2 if other. But this wasn't good way to do. So how should it be done. My code:
在我返回一个 int 之前，如果不是，则为 0，如果是，则为 1，如果其他，则为 2。但这可不是什么好办法。那么应该怎么做。我的代码：
class SomeClass{
public enum decizion{
YES, NO, OTHER
}
public static enum yourDecizion(){
//scanner etc
if(x.equals('Y')){
return YES;
}
else if (x.equals('N')){
return NO;
}
else{
return OTHER;
}
}
}
采纳答案by Konstantin Yovkov
I don't what the "//scanner etc." does, but the methods return type should be decizion:
我不知道“//扫描仪等” 确实如此，但方法返回类型应该是decizion：
public static decizion yourDecizion() { ... }
Furthermore, you can add the Y, N, etc. values to the enum constants:
此外，您可以将Y、N等值添加到枚举常量中：
public enum decizion{
YES("Y"), NO("N"), OTHER;
String key;
decizion(String key) { this.key = key; }
//default constructor, used only for the OTHER case,
//because OTHER doesn't need a key to be associated with.
decizion() { }
decizion getValue(String x) {
if ("Y".equals(x)) { return YES; }
else if ("N".equals(x)) { return NO; }
else if (x == null) { return OTHER; }
else throw new IllegalArgumentException();
}
}
Then, in the method, you can just do:
然后，在该方法中，您可以执行以下操作：
public static decizion yourDecizion() {
...
String key = ...
return decizion.getValue(key);
}
回答by Axel
Change your code to:
将您的代码更改为：
class SomeClass{
public enum decizion {
YES, NO, OTHER
}
public static decizion yourDecizion(){
//scanner etc
if(x.equals('Y')){
return decizion.YES;
}
else if (x.equals('N')){
return decizion.NO;
}
else{
return decizion.OTHER;
}
}
}
Note: The method return type must be decizioninstead of enumand decizionshould have an upper case name (as all classes should).
注意：方法返回类型必须是decizion而不是enum并且decizion应该有一个大写的名称（所有类都应该如此）。
回答by Eduardo
I think you should do something like these, an enum class. Then u can add as many types u want and the method yourDecizion() will return the enum type depending on the given parameter.
我认为你应该做这样的事情，一个枚举类。然后您可以添加任意数量的类型，并且 yourDecizion() 方法将根据给定的参数返回枚举类型。
public enum SomeClass {
YES(0),
NO(1),
OTHER(2);
private int code;
private SomeClass(int code) {
this.code = code;
}
public int getCode() {
return code;
}
public static SomeClass yourDecizion(int x) {
SomeClass ret = null;
for (SomeClass type : SomeClass.values()) {
if (type.getCode() == x)
ret = type;
}
return ret;
}
}
