Java 如何为自己的注释创建可选参数？
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How to create optional parameters for own annotations?
提问by Biju CD
Following is the annotation code
以下是注释代码
public @interface ColumnName {
String value();
String datatype();
}
I would like to make datatypean optional parameter, for example
我想做datatype一个可选参数，例如
@ColumnName(value="password")
should be a valid code.
应该是有效的代码。
采纳答案by Riduidel
Seems like the first example in the official documentationsays it all ...
/**
* Describes the Request-For-Enhancement(RFE) that led
* to the presence of the annotated API element.
*/
public @interface RequestForEnhancement {
int id();
String synopsis();
String engineer() default "[unassigned]";
String date() default "[unimplemented]";
}
回答by Johannes Wachter
To make it optional you can assign it a default value like that:
要使其可选，您可以为它分配一个默认值，如下所示：
public @interface ColumnName {
String value();
String datatype() default "String";
}
Then it doesn't need to be specified when using the Annotation.
那么在使用 Annotation 时就不需要指定了。
