Java get all variable names in a class

Question

I have a class and I want to find all of its public fields  not methods   How can I do this   Thanks

User · Answer

https   docs oracle com javase tutorial reflect class classMembers html also has charts for locating methods and constructors

User · Answer

As mentioned by few users  below code can help find all the fields in a given class   TestClass testObject  new TestClass   getClass    Method   methods   testObject getMethods    for  Method method methods        String name method getName        if name startsWith  get                  System out println name substring 3         else if name startsWith  is                  System out println name substring 2              However a more interesting approach is below   With the help of Jackson library  I was able to find all class properties of type String integer double  and respective values in a Map class   without using reflections api    TestClass testObject   new TestClass    com fasterxml jackson databind ObjectMapper m   new com fasterxml jackson databind ObjectMapper     Map lt String Object gt  props   m convertValue testObject  Map class    for Map Entry lt String  Object gt  entry   props entrySet         if entry getValue   instanceof String    entry getValue   instanceof Integer    entry getValue   instanceof Double           System out println entry getKey      -- gt     entry getValue

User · Answer

Field   fields   YourClassName class getFields      returns an array of all public variables of the class   getFields   return the fields in the whole class-heirarcy  If you want to have the fields defined only in the class in question  and not its superclasses  use getDeclaredFields    and filter the public ones with the following Modifier approach   Modifier isPublic field getModifiers       The YourClassName class literal actually represents an object of type java lang Class   Check its docs for more interesting reflection methods   The Field class above is java lang reflect Field  You may take a look at the whole java lang reflect package

User · Answer

You can use any of the two based on your need   Field   fields   ClassName class getFields       returns inherited members but not private members  Field   fields   ClassName class getDeclaredFields       returns all members including private members but not inherited members    To filter only the public fields from the above list  based on requirement  use below code   List lt Field gt  fieldList   Arrays asList fields  stream   filter field - gt  Modifier isPublic field getModifiers     collect      Collectors toList

[java] Java: get all variable names in a class

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