Boa tarde.
Eu tenho um JComboBox que lista itens de uma tabela do Mysql, e ao selecionar o item deste combobox, preciso que seus dados sejam setados em texts fields. Mas ele me apresenta o erro “java.lang.NullPointerException”. Utilizo o código abaixo:
private void jcbProdutosActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
try {
String query = "SELECT * FROM produtos WHERE nome = ?";
PreparedStatement pst = conn.prepareStatement(query);
pst.setString(1, (String)jcbProdutos.getSelectedItem());
ResultSet rs = pst.executeQuery();
while(rs.next()){
tfCodProd.setText(rs.getString("codigo"));
tfValorUn.setText(rs.getString("nome"));
}
pst.close();
} catch (Exception e) {
e.printStackTrace();
}
}
Faz um tempinho que não mexo com java mas ainda tenho alguns trabalhinhos assim que fiz em sala, vou ver se consigo ajudar…
Em qual linha ele está apontando erro de NullPointer?
Coloquei o erro completo aí. Mas deu pra entender o que eu quero fazer? Estou no caminho certo?
run:
java.lang.NullPointerException
at view.ViewVenda.jcbProdutosActionPerformed(ViewVenda.java:679)
at view.ViewVenda.access$600(ViewVenda.java:32)
at view.ViewVenda$8.actionPerformed(ViewVenda.java:289)
at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1258)
at javax.swing.JComboBox.contentsChanged(JComboBox.java:1332)
at javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:118)
at javax.swing.DefaultComboBoxModel.setSelectedItem(DefaultComboBoxModel.java:93)
at javax.swing.DefaultComboBoxModel.addElement(DefaultComboBoxModel.java:131)
at javax.swing.JComboBox.addItem(JComboBox.java:716)
at view.ViewVenda.listarProdutos(ViewVenda.java:72)
at view.ViewVenda.<init>(ViewVenda.java:60)
at view.ViewVenda$17.run(ViewVenda.java:895)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
java.lang.NullPointerException
at view.ViewVenda.jcbProdutosActionPerformed(ViewVenda.java:679)
at view.ViewVenda.access$600(ViewVenda.java:32)
at view.ViewVenda$8.actionPerformed(ViewVenda.java:289)
at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1258)
at javax.swing.JComboBox.setSelectedItem(JComboBox.java:586)
at javax.swing.JComboBox.setSelectedIndex(JComboBox.java:622)
at view.ViewVenda.desabilitarCampos(ViewVenda.java:497)
at view.ViewVenda.<init>(ViewVenda.java:64)
at view.ViewVenda$17.run(ViewVenda.java:895)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
java.lang.NullPointerException
at view.ViewVenda.jcbProdutosActionPerformed(ViewVenda.java:679)
at view.ViewVenda.access$600(ViewVenda.java:32)
at view.ViewVenda$8.actionPerformed(ViewVenda.java:289)
at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1258)
at javax.swing.JComboBox.contentsChanged(JComboBox.java:1332)
at javax.swing.JComboBox.intervalRemoved(JComboBox.java:1352)
at javax.swing.AbstractListModel.fireIntervalRemoved(AbstractListModel.java:179)
at javax.swing.DefaultComboBoxModel.removeAllElements(DefaultComboBoxModel.java:174)
at javax.swing.JComboBox.removeAllItems(JComboBox.java:771)
at view.ViewVenda.listarProdutos(ViewVenda.java:70)
at view.ViewVenda.novoProduto(ViewVenda.java:810)
at view.ViewVenda.jbNovaVendaActionPerformed(ViewVenda.java:615)
at view.ViewVenda.access$400(ViewVenda.java:32)
at view.ViewVenda$5.actionPerformed(ViewVenda.java:226)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
java.lang.NullPointerException
at view.ViewVenda.jcbProdutosActionPerformed(ViewVenda.java:679)
at view.ViewVenda.access$600(ViewVenda.java:32)
at view.ViewVenda$8.actionPerformed(ViewVenda.java:289)
at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1258)
at javax.swing.JComboBox.contentsChanged(JComboBox.java:1332)
at javax.swing.AbstractListModel.fireContentsChanged(AbstractListModel.java:118)
at javax.swing.DefaultComboBoxModel.setSelectedItem(DefaultComboBoxModel.java:93)
at javax.swing.DefaultComboBoxModel.addElement(DefaultComboBoxModel.java:131)
at javax.swing.JComboBox.addItem(JComboBox.java:716)
at view.ViewVenda.listarProdutos(ViewVenda.java:72)
at view.ViewVenda.novoProduto(ViewVenda.java:810)
at view.ViewVenda.jbNovaVendaActionPerformed(ViewVenda.java:615)
at view.ViewVenda.access$400(ViewVenda.java:32)
at view.ViewVenda$5.actionPerformed(ViewVenda.java:226)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
java.lang.NullPointerException
at view.ViewVenda.jcbProdutosActionPerformed(ViewVenda.java:679)
at view.ViewVenda.access$600(ViewVenda.java:32)
at view.ViewVenda$8.actionPerformed(ViewVenda.java:289)
at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1258)
at javax.swing.JComboBox.setSelectedItem(JComboBox.java:586)
at javax.swing.JComboBox.setSelectedIndex(JComboBox.java:622)
at javax.swing.plaf.basic.BasicComboPopup$Handler.mouseReleased(BasicComboPopup.java:852)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:290)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at javax.swing.plaf.basic.BasicComboPopup$1.processMouseEvent(BasicComboPopup.java:501)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
CONSTRUÍDO COM SUCESSO (tempo total: 17 segundos)
Bruno,
puxei meus códigos e achei o seguinte:
public boolean recuperarTudo(Conexao c, LinkedList<Endereco> listaUFs) {
try {
Statement st;
st = c.getCon().createStatement();
ResultSet rs = st.executeQuery("SELECT * FROM estado");
if(rs!=null){
while(rs.next()){
Endereco endereco = new Endereco();
endereco.setUf(rs.getString("uf"));
listaUFs.add(endereco);
}
}
return true;
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
Veja que é necessário um teste de if(rs!=null) pois o retorno daquela Query pode ser vazia, dai estarás tentando acessar a função next() de um objeto nulo, resultando no erro que estás tendo.
Tenta colocar aquele IF e ve se vai dar certo.
Mantenha-me informado.
Abraço
O método executeQuery nunca retorna null. Não é necessário fazer esse if.
Qual dessas é a linha 679 do código? (Linha onde a exception aponta o erro)?
A linha 679 é esta:
PreparedStatement pst = conn.prepareStatement(query);
Com o “if” também não deu certo
Estou desenvolvendo um projeto estou querendo fazer isso tambem
Se conseguir a resposat me avisa porfavor
Provavelmente a variável conn não foi inicializada.