apache poi - Create in a textbox excel with java -

i have document excel textboxes want create in textboxes text java code code value , how i'm going edit using poid apache

    try {      fileinputstream fsip = new fileinputstream(new file("c:\\book1.xls"));       //   inputstream input = new fileinputstream("book1.xls");         poifsfilesystem fs = new poifsfilesystem(fsip);         hssfworkbook wb = new hssfworkbook(fs);         hssfsheet sheet = wb.getsheetat(0);         hssfpatriarch pat = sheet.getdrawingpatriarch();         list children = pat.getchildren();          iterator = children.iterator();         while (it.hasnext()) {             hssfshape shape = (hssfshape) it.next();             if (shape instanceof hssftextbox) {                  shape.getanchor()                 hssftextbox textbox = (hssftextbox) shape;                 hssfrichtextstring richstring = textbox.getstring();                 string str = richstring.getstring();                 system.out.println("string: " + str);                 system.out.println("string length: " + str.length());             }         }     } catch (ioexception ex) {         ex.printstacktrace();     }