get the annotation information at runtime

Question

I wonder if there is any way I can get the annotation information of a class at runtime? Since I want to get the properties that sepcifily annotated.

Example:

class TestMain {
    @Field(
            store = Store.NO)
    private String  name;
    private String  password;
    @Field(
            store = Store.YES)
    private int     age;

    //..........getter and setter
}

The annotations come from the hibernate-search,and now what I want is get which property of the "TestMain" is annotated as a 'field'(in the example,they are [name,age]),and which is 'stored(store=store.yes)'(in the example,they are [age]) at runtime.

Any ideas?

UPDATe:

public class FieldUtil {
public static List<String> getAllFieldsByClass(Class<?> clazz) {
    Field[] fields = clazz.getDeclaredFields();
    ArrayList<String> fieldList = new ArrayList<String>();
    ArrayList<String> storedList=new ArrayList<String>();
    String tmp;
    for (int i = 0; i < fields.length; i++) {
        Field fi = fields[i];
        tmp = fi.getName();
        if (tmp.equalsIgnoreCase("serialVersionUID"))
            continue;
        if (fi.isAnnotationPresent(org.hibernate.search.annotations.Field.class)) {
            //it is a "field",add it to list.
            fieldList.add(tmp);

            //make sure if it is stored also
            Annotation[] ans = fi.getAnnotations();
            for (Annotation an : ans) {
                //here,how to get the detail annotation information
                //I print the value of an,it is something like this:
                //@org.hibernate.search.annotations.Field(termVector=NO, index=UN_TOKENIZED, store=NO, name=, [email protected](value=1.0), [email protected](impl=void, definition=), [email protected](impl=void, params=[]))

                //how to get the parameter value of this an? using the string method?split?
            }
        }

    }
    return fieldList;
}

}

Answer 1

Yes, of course. Your code sample does not actually get annotation information for class, but for fields, but code is similar. You just need to get Class, Method or Field you are interested in, then call "getAnnotation(AnnotationClass.class)" on it.

The only other thing to notice is that annotation definition must use proper RetentionPolicy so that annotation information is stored in byte code. Something like:

@Target({ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation { ... }