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我有枚举类
public enum PaymentType {
/**
* This notify type we receive when user make first subscription payment.
*/
SUBSCRIPTION_NEW("subscr_signup"),
/**
* This notify type we receive when user make subscription payment for next
* month.
*/
SUBSCRIPTION_PAYMENT("subscr_payment"),
/**
* This notify type we receive when user cancel subscription from his paypal
* personal account.
*/
SUBSCRIPTION_CANCEL("subscr_cancel"),
/**
* In this case the user cannot change the amount or length of the
* subscription, they can however change the funding source or address
* associated with their account. Those actions will generate the
* subscr_modify IPN that we are receiving.
*/
SUBSCRIPTION_MODIFY("subscr_modify"),
/**
* Means that the subscription has expired, either because the subscriber
* cancelled it or it has a fixed term (implying a fixed number of payments)
* and it has now expired with no further payments being due. It is sent at
* the end of the term, instead of any payment that would otherwise have
* been due on that date.
*/
SUBSCRIPTION_EXPIRED("subscr_eot"),
/** User have no money on card, CVV error, another negative errors. */
SUBSCRIPTION_FAILED("subscr_failed");
private String type;
PaymentType(String type) {
this.type = type;
}
String getType() {
return type;
}
}
尝试创建枚举时：
PaymentType type = PaymentType.valueOf("subscr_signup");
Java向我抛出错误：
IllegalArgumentException occured : No enum constant models.PaymentType.subscr_signup
我怎么能解决这个问题？
我认为您必须在枚举中编写一个比较方法
stackoverflow.com/a/2965252/5188230
创建额外的静态方法，该方法将搜索枚举的值
@不是复制品。如果字符串不是同一枚举值，则提供的示例不是解决方案。
@Gregkopff提供了正确的答案。
@ssh你读过所提供问题的第二个答案了吗？
@ssh您可能希望滚动一点，而不仅仅是为了获得已接受的答案。
@谢谢你。那是我要找的！
添加并使用此方法
public static PaymentType parse(String type) {
for (PaymentType paymentType : PaymentType.values()) {
if (paymentType.getType().equals(type)) {
return paymentType;
}
}
return null; //or you can throw exception
}
对。它是正确的。
枚举尚未准备好对此使用方法。您要么需要使用准确的字段名：
PaymentType.valueOf("SUBSCRIPTION_MODIFY");
或者编写自己的方法，例如：
public static PaymentType fromString(String string) {
for (PaymentType pt : values()) {
if (pt.getType().equals(string)) {
return pt;
}
}
throw new NoSuchElementException("Element with string" + string +" has not been found");
}
所以这个代码：
public static void main(String[] args) {
System.out.println(PaymentType.fromString("subscr_modify"));
}
印刷品：
SUBSCRIPTION_MODIFY
subscr_signup
是枚举变量值，而不是枚举值。因此，如果要根据枚举的值名称获取枚举，则必须这样做：
PaymentType type = PaymentType.valueOf("SUBSCRIPTION_NEW");
Enum类.valueOf()方法将传递给它的字符串与枚举实例的name属性(实例名称的实际值)进行比较，因此在您的示例中，这将是"SUBSCRIPTION_NEW"而不是"subscr_signup"。
您需要编写一个静态方法，该方法为给定值返回正确的枚举实例。例如：
public static PaymentType byTypeString(String type) {
for (PaymentType instance : values()) {
if (instance.type.equals(type)) {
return instance;
}
}
throw new IllegalArgumentException("No PaymentType enum instance for type:" + type);
}
我不能用它。
为什么不？如果不能修改paymentType枚举，只需将其作为静态方法添加到其他地方，使用getType()访问器而不是直接使用type。
valueOf返回其标识符与您传入的字符串匹配的枚举项。例如：
PaymentType t = PaymentType.valueOf("SUBSCRIPTION_NEW");
如果要获取其type字段与给定字符串匹配的枚举项，请在PaymentType上编写一个静态方法，该方法通过PaymentType.values()循环并返回匹配项。
我不能用它，因为我不能改变常量。
当然你可以写一个方法。