是否可以在运行时在Java中读取带注释的字段值？

Question

I have a class like follow, with MyAnnotation:

public class MyClass {

    @MyAnnotation
    public boolean bool;

    public boolean getBool(){
        return bool;
    }

    public voud setBool(boolean b){
        bool = b;
    }
}

It is possible to get the value of bool at runtime through the annotation?

EDIT: this is that I was looking for:

     public void validate(Object o) throws OperationNotSupportedException {

          Field[] flds = o.getClass().getDeclaredFields();
          for (Field field : flds) {
             if (field.isAnnotationPresent(NotNull.class)) {
                String fieldName = field.getName();
                Method m;
                Object value;

                try {
                   m = o.getClass().getMethod("get" + capitalize(fieldName), null);
                   value = m.invoke(o, null);
                   if (value == null) {
                      throw new OperationNotSupportedException("Field '" + fieldName + "' must be initialized.");
                   }
                } catch (Exception e) {
                   e.printStackTrace();
                }
             }
          }
       }
   private String capitalize(final String line) {
      return Character.toUpperCase(line.charAt(0)) + line.substring(1);
   }

Answer 1

Not sure if this is what you're looking for but you can do something like this:

Object getValueForMyAnnotaion(MyClass obj) {
   Field[] fieldList = obj.getClass().getDeclaredFields();

   for (Field field : fieldList) {
       if (field.isAnnotationPresent(MyAnnotation.class)) {
          return field.get(obj);
       }
   }
}

Note that it will return Object and only for the first member that has the annotation but it can be easily changed to what you need.