Re: [JAVA] creating instance of the class

[Niall Pemberton]

On 2/9/07, temp temp <[EMAIL PROTECTED]> wrote:

    I want to  create  instance of a class  using object.getClass().new 
Instance()   but  this object constructor needs another object  so how can I do 
this ?


      Suppose I  have a class

      DefaultMetaInfoHandler   default=new DefaultMetaInfo("test");

      Can I  create instance of this class using  
default.getClass().newInstance()

You can't - you have to get hold of the constructor that has the
single argument and invoked it. So using your example - a constructor
that takes a single String parameter:

  Class clazz = DefaultMetaInfo.class;
  Classs[] paramTypes = new Class[] {String.class};

  // Get the constructor
  Constructor ctor = clazz.getConstructor(paramTypes);

   // Create a new instance
   Object[] args = new Object[] {"test"};
   DefaultMetaInfoHandler default =
(DefaultMetaInfoHandler)ctor.newInstance(args)

BeanUtils has convenience methods to do this - including one for a
constructor that takes a single argument:

  http://tinyurl.com/2hgkrm

So using BeanUtils al you need to do is:

  DefaultMetaInfoHandler default = (DefaultMetaInfoHandler)
              ConstructorUtils.invokeConstructor(DefaultMetaInfo.class,
"test");

Niall

  If I have to create how ?

  Thanks
  Miro

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