java - Jtable Select row and columns -

i want select row , column of jtable's cell , print value, in public void changevalue(),as shown below, got error:

exception in thread "main" java.lang.arrayindexoutofboundsexception: -1 @ java.util.vector.elementdata(unknown source) @ java.util.vector.elementat(unknown source) @ javax.swing.table.defaulttablemodel.getvalueat(unknown source) @ javax.swing.jtable.getvalueat(unknown source) @ shopmanagement.showemployee.changevalue(showemployee.java:81) @ shopmanagement.showemployee.<init>(showemployee.java:74) @ shopmanagement.showemployee.main(showemployee.java:87)

maybe,have implement mouselistener used check current position of cursor in jtable?

if so,how can change code?

import java.awt.*; import java.sql.*; import java.util.*;  import javax.swing.*;  import databaseconnectionsingleton.connection; import databaseconnectionsingleton.creationstatement;  public class showemployee extends jframe { public jtable table = new jtable();  public showemployee() { vector<string> columnnames = new vector<string>(); vector<vector<object>> data = new vector<vector<object>>();  try {      connection.getconnectioninstance();     statement st = creationstatement.getcreationstatementinstance();     resultset rs = st.executequery("select * employee");     resultsetmetadata md = rs.getmetadata();     int columns = md.getcolumncount();      // column names      (int = 1; <= columns; i++) {         columnnames.addelement(md.getcolumnname(i));     }      // row data      while (rs.next()) {         vector<object> row = new vector<object>(columns);          (int = 1; <= columns; i++) {             row.addelement(rs.getobject(i));         }          data.addelement(row);     } } catch (exception e) {     system.out.println(e); }  // create table database data  table = new jtable(data, columnnames) {     /**      *       */     private static final long serialversionuid = 1l;      public class<?> getcolumnclass(int column) {         (int row = 0; row < getrowcount(); row++) {             object o = getvalueat(row, column);              if (o != null) {                 return o.getclass();             }         }          return object.class;     } };  jscrollpane scrollpane = new jscrollpane(table); getcontentpane().add(scrollpane);  jpanel buttonpanel = new jpanel(); getcontentpane().add(buttonpanel, borderlayout.south); changevalue(); }  public void changevalue() {  int rowindex = table.getselectedrow(); int colindex = table.getselectedcolumn(); string s=(string) table.getvalueat(rowindex,colindex); system.out.println("innertable:" + rowindex + "*" + colindex+" "+s);  }  public static void main(string[] args) { showemployee frame = new showemployee(); frame.setdefaultcloseoperation(exit_on_close); frame.pack(); frame.setvisible(true); } } 

thanks in advance.

as calling changevalue() on form load , gives rowindx , columnindex -1 because nothing selected on form load.

you can using jbutton's actionlistener method. want print selected data add button called print.you can use actionlistener on print button.

look @ example

public class tablevalueprint extends jframe implements actionlistener{     private final jbutton print;     private final jtable table;      public tablevalueprint() {          string[] columnnames = {"a", "b", "c"};         object[][] data = {             {"moni", "adsad", "pass"},             {"jhon", "ewrewr", "fail"},             {"max", "zxczxc", "pass"}         };          table = new jtable(data, columnnames);         jscrollpane tablesp = new jscrollpane(table);         jpanel tablepanel = new jpanel();         tablepanel.add(tablesp);         tablepanel.setbackground(color.red);         add(tablepanel);         settitle("result");          setsize(1000,700);          print=new jbutton("print");           jpanel jpi1 = new jpanel();           jpi1.add(print);           tablepanel.add(jpi1,borderlayout.south);                print.addactionlistener(this);         setlocationrelativeto(null);         setdefaultcloseoperation(exit_on_close);     }      public static void main(string[] args) {         swingutilities.invokelater(new runnable() {              public void run() {                 tablevalueprint ex = new tablevalueprint();                 ex.setvisible(true);             }         });     }      @override     public void actionperformed(actionevent ae) {        if(ae.getsource()==print){          int rowindex = table.getselectedrow();          int colindex = table.getselectedcolumn();          string s=(string) table.getvalueat(rowindex,colindex);          system.out.println("innertable:" + rowindex + "*" + colindex+" "+s);         }     } } 

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output :

innertable:0*1 adsad innertable:2*2 pass innertable:1*1 ewrewr innertable:2*0 max