我是编程的初学者，所以尽可能帮助我！ 我正在做一个选择DataBase（MySQL）的程序，具体取决于用户选择要搜索的内容。 Programm有4种不同的搜索内容：Artigo，Cliente，Vendedor和拥有2个jDateChoosers的数据（它将在第一个日期和第二个日期之间进行查询）。 因此，如果条件能够捕捉到所有可能的组合，我将需要16个。
这里有关于一个事件的代码，jTextFieldClienteKeyReleased，考虑到代码在所有其他TextFieldsKeyReleaseds和jDateChoosersMouseClicked中重复等等。
private void jTextFieldPorVendedorKeyReleased(java.awt.event.KeyEvent evt) {
// TODO add your handling code here
// Se artigo, cliente, vendedor e data forem pesquisados fazer a seguinte consulta SQL
SimpleDateFormat sd1 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial1 = sd1.format(jDateChooserInicial.getDate());
SimpleDateFormat sd2 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal1 = sd2.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
PreparedStatement preparedStatement; //1 SELECT * FROM fatura WHERE CodArt LIKE '%AES%' AND CodCli = 1 AND CodVendedor = 1 AND Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ " CodCli = "
+ jTextFieldPorCliente.getText()
+ " AND "
+ "CodVendedor = "
+ jTextFieldPorVendedor.getText()
+ " AND "
+ "Data >= '"
+ DataInicial1
+ "' AND "
+ " Data <= '"
+ DataFinal1
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
//Se artigo, cliente e vendedor estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd3 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial2 = sd3.format(jDateChooserInicial.getDate());
SimpleDateFormat sd4 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal2 = sd4.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial2 == null )) || ((DataFinal2 == null ))) /*|| (jDateChooserInicial.getDateFormatString().contains("yyyy-MM-dd")) || (jDateChooserFinal.getDateFormatString().contains("yyyy-MM-dd")))*/ {
try {
PreparedStatement preparedStatement; //2 SELECT * FROM fatura WHERE CodArt LIKE '%39%' AND CodCli = 1 AND CodVendedor = 1
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ "CodCli = "
+ jTextFieldPorCliente.getText()
+ " AND "
+ "CodVendedor = "
+ jTextFieldPorVendedor.getText()
+ "");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se artigo, cliente e data estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd5 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial3 = sd5.format(jDateChooserInicial.getDate());
SimpleDateFormat sd6 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal3 = sd6.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
PreparedStatement preparedStatement; //3 SELECT * FROM fatura WHERE CodArt = 2 AND CodCli = 1 AND Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ " CodCli = "
+ jTextFieldPorCliente.getText()
+ " AND "
+ " Data >= '"
+ DataInicial3
+ "' AND "
+ " Data <= '"
+ DataFinal3
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se artigo e cliente estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd7 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial4 = sd7.format(jDateChooserInicial.getDate());
SimpleDateFormat sd8 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal4 = sd8.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial4 == null )) || ((DataFinal4 == null ))) {
try {
PreparedStatement preparedStatement; //4 SELECT * FROM fatura WHERE CodArt = 1 AND CodCli = 1
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ " CodCli = "
+ jTextFieldPorCliente.getText()
+ "");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se artigo, vendedor e data estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd9 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial5 = sd9.format(jDateChooserInicial.getDate());
SimpleDateFormat sd10 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal5 = sd10.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
PreparedStatement preparedStatement; //5 SELECT * FROM fatura WHERE CodArt = 2 AND CodVendedor = 1 AND Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ " CodVendedor = "
+ jTextFieldPorVendedor.getText()
+ " AND "
+ " Data >= '"
+ DataInicial5
+ "' AND "
+ " Data <= '"
+ DataFinal5
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se artigo e vendedor estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd11 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial6 = sd11.format(jDateChooserInicial.getDate());
SimpleDateFormat sd12 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal6 = sd12.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial6 == null )) || ((DataFinal6 == null ))){
try {
PreparedStatement preparedStatement; //6 SELECT * FROM fatura WHERE CodArt = 1 AND CodVendedor = 2
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ " CodVendedor = "
+ jTextFieldPorVendedor.getText()
+ "");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se artigo e data estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd13 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial7 = sd13.format(jDateChooserInicial.getDate());
SimpleDateFormat sd14 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal7 = sd14.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))){
try {
PreparedStatement preparedStatement; //7 SELECT * FROM fatura WHERE CodArt = 2 AND Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%' AND "
+ " Data >= '"
+ DataInicial7
+ "' AND "
+ " Data <= '"
+ DataFinal7
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se apenas artigo estiver a ser pesquisado fazer a seguinte consulta SQL
}
SimpleDateFormat sd15 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial8 = sd15.format(jDateChooserInicial.getDate());
SimpleDateFormat sd16 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal8 = sd16.format(jDateChooserFinal.getDate());
if(!(jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial8 == null )) || ((DataFinal8 == null ))){
try {
PreparedStatement preparedStatement; //8 SELECT * FROM `fatura` WHERE CodArt LIKE '%AM%'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodArt LIKE '%"
+ jTextFieldPorArtigo.getText()
+ "%'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
答案 0 :(得分：0)
（这是代码的继续，我无法将所有代码放在同一个问题中，它有字符限制）
// Se cliente, vendedor e data estiverem a ser pesquisados fazer a seguinte consulta SQL
} if((jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
SimpleDateFormat sd17 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial9 = sd17.format(jDateChooserInicial.getDate());
SimpleDateFormat sd18 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal9 = sd18.format(jDateChooserFinal.getDate());
PreparedStatement preparedStatement; //9 SELECT * FROM fatura WHERE CodCli = 1 AND CodVendedor = 2 Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodCli ="
+ jTextFieldPorCliente.getText()
+ " AND "
+ " CodVendedor = "
+ jTextFieldPorVendedor.getText()
+ " AND "
+ " Data >= '"
+ DataInicial9
+ "' AND "
+ " Data <= '"
+ DataFinal9
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se cliente e vendedor estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd19 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial10 = sd19.format(jDateChooserInicial.getDate());
SimpleDateFormat sd20 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal10 = sd20.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial10 == null )) || ((DataFinal10 == null ))) {
try {
PreparedStatement preparedStatement; //10 SELECT * FROM fatura WHERE CodCli = 1 AND CodVendedor = 2
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodCli ="
+ jTextFieldPorCliente.getText()
+ " AND "
+ " CodVendedor = "
+ jTextFieldPorVendedor.getText()
+ "");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se cliente e data estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd21 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial11 = sd21.format(jDateChooserInicial.getDate());
SimpleDateFormat sd22 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal11 = sd22.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
PreparedStatement preparedStatement; //11 SELECT * FROM fatura WHERE CodCli = 1 AND Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodCli ="
+ jTextFieldPorCliente.getText()
+ " AND "
+ " Data >= '"
+ DataInicial11
+ "' AND "
+ " Data <= '"
+ DataFinal11
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se apenas cliente estiver a ser pesquisado fazer a seguinte consulta SQL
}
SimpleDateFormat sd23 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial12 = sd23.format(jDateChooserInicial.getDate());
SimpleDateFormat sd24 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal12 = sd24.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && (!(jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial12 == null )) || ((DataFinal12 == null ))) {
try {
PreparedStatement preparedStatement; //12 SELECT * FROM fatura WHERE CodCli = 1
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodCli = "
+ jTextFieldPorCliente.getText()
+ "");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se vendedor e data estiverem a ser pesquisados fazer a seguinte consulta SQL
}
SimpleDateFormat sd25 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial13 = sd25.format(jDateChooserInicial.getDate());
SimpleDateFormat sd26 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal13 = sd26.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
PreparedStatement preparedStatement; //13 SELECT * FROM fatura WHERE CodVendedor = 2 AND Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodVendedor ="
+ jTextFieldPorVendedor.getText()
+ " AND "
+ " Data >= '"
+ DataInicial13
+ "' AND "
+ " Data <= '"
+ DataFinal13
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se apenas vendedor estiver a ser pesquisado fazer a seguinte consulta SQL
}
SimpleDateFormat sd27 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial14 = sd27.format(jDateChooserInicial.getDate());
SimpleDateFormat sd28 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal14 = sd28.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && (!(jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial14 == null )) || ((DataFinal14 == null ))) {
try {
PreparedStatement preparedStatement; //14 SELECT * FROM fatura WHERE CodVendedor = 2
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE CodVendedor ="
+ jTextFieldPorVendedor.getText()
+ "");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se apenas data estiver a ser pesquisada fazer a seguinte consulta SQL
}
SimpleDateFormat sd29 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial15 = sd29.format(jDateChooserInicial.getDate());
SimpleDateFormat sd30 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal15 = sd30.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (!(jDateChooserInicial.getDate().toString().isEmpty())) && (!(jDateChooserFinal.getDate().toString().isEmpty()))) {
try {
PreparedStatement preparedStatement; //15 SELECT * FROM fatura WHERE Data >= '2015/03/25' AND Data <= '2017/02/27'
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura WHERE Data >= '"
+ DataInicial15
+ "' AND "
+ " Data <= '"
+ DataFinal15
+ "'");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
// Se nenhum campo estiver a ser pesquisado fazer a seguinte consulta SQL
}
SimpleDateFormat sd31 = new SimpleDateFormat("yyyy-MM-dd");
String DataInicial16 = sd31.format(jDateChooserInicial.getDate());
SimpleDateFormat sd32 = new SimpleDateFormat("yyyy-MM-dd");
String DataFinal16 = sd32.format(jDateChooserFinal.getDate());
if((jTextFieldPorArtigo.getText().isEmpty()) && ((jTextFieldPorCliente.getText().isEmpty())) && ((jTextFieldPorVendedor.getText().isEmpty())) && (jDateChooserInicial.getDate().toString().isEmpty()) && (jDateChooserFinal.getDate().toString().isEmpty()) || ((DataInicial16 == null )) || ((DataFinal16 == null ))) {
try {
PreparedStatement preparedStatement; //16 SELECT * FROM fatura
preparedStatement = ligacao.prepareStatement("SELECT * FROM fatura");
System.out.println(preparedStatement);
ResultSet resultSetForFullTable = preparedStatement.executeQuery();
jTableVendas.setModel(DbUtils.resultSetToTableModel(resultSetForFullTable));
} catch (SQLException ex) {
System.out.println(ex);
}
}
当用户搜索任何同时数据进展顺利的内容时，问题是当用户不需要查询数据并需要其他数据时，就会出错。
当我在jDateChooser中没有设置数据的情况下进行搜索时，错误是NullPointerException，我试图阅读很多帖子但是没有人帮助我！
这是错误：
run:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.util.Calendar.setTime(Calendar.java:1770)
at java.text.SimpleDateFormat.format(SimpleDateFormat.java:943)
at java.text.SimpleDateFormat.format(SimpleDateFormat.java:936)
at java.text.DateFormat.format(DateFormat.java:345)
at projeto_mitjavilla_ricardo.ListarVenda.jTextFieldPorArtigoKeyReleased(ListarVenda.java:2266)
at projeto_mitjavilla_ricardo.ListarVenda.access$200(ListarVenda.java:28)
at projeto_mitjavilla_ricardo.ListarVenda$4.keyReleased(ListarVenda.java:155)
at java.awt.Component.processKeyEvent(Component.java:6496)
at javax.swing.JComponent.processKeyEvent(JComponent.java:2832)
at java.awt.Component.processEvent(Component.java:6312)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
(...)
希望有人能够理解问题是什么并弄清楚，如果有人不明白我想做什么，请问我，我会尽力回答最好的方法。
p.s这是我第一次在论坛上发布任何内容，所以如果我在这个论坛上发帖做错了，请告诉我，我会尝试更好。