CODEWITHSUNDEEP
javafileclassannotations
blaces
blaces

Reputation: 495

How read an annotation file?

I dont'know that, how can I read a file. I would like to read the FK.java file, but give me a class not found exception. FK is annotation java file. (I have tried "src/annotations/FK.java" but didn't work.

private static String clazz = "src/annotations/FK";

public static List<Object> GetAnnotations() throws ClassNotFoundException{

    Class<?> c;
    c = Class.forName(clazz);

    List<Object> result = new ArrayList();


    Field[] fields = c.getDeclaredFields();
    for (int j = 0; j < fields.length; j++)
    {
        Annotation[] annot = fields[j].getAnnotations();
        for (int k = 0; k < annot.length; k++)
        {
            result.add(annot[k].annotationType());
        }
    }
    return result;
}

public static void main(String[] args) throws ClassNotFoundException {
    System.out.println(GetAnnotations());
}

Upvotes: 0

Views: 823

Answers (2)

Kallja
Kallja

Reputation: 5472

Your problem is, that you're trying to get the Class object for your annotated class with the wrong syntax.

The Class.forName(String)-method takes a fully qualified Java class name as a parameter. That is the name of the package containing the class as declared in your Java-file immediately followed by your class name. In your case that is probably "annotations.FK".

An other note is that simply having the Java-source code file for the class will not do. You will need to have the compiled class in your classpath.

Here is a simple example:

// mytoplevelpackage/mypackage/MyClass.java

package mytoplevelpackage.mypackage;

public class MyClass {}


// mytoplevelpackage/OtherClass.java

package mytoplevelpackage;

public class OtherClass {
  public static void main(String[] args) throws ClassNotFoundException {
    Class c = Class.forName("mytoplevelpackage.mypackage.MyClass");
  }
}

Upvotes: 0

Attila
Attila

Reputation: 28762

The name of the class should contain dots (.) not slashes ('/')

private static String clazz = "annotations.FK";

Then

Class.forName(clazz);

will try to load the class annotations/FK.class from the provided classpath. If you only have the .java file, you will need to compile it first.

EDIT: fixed path based on comments

Upvotes: 1

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