【发布时间】：2014-10-15 16:25:17
【问题描述】：
我正在开发一个使用 JDBC ODBC 连接连接到 Ms Sql 服务器的在线考试软件。我想将结果集光标移动到下一行并向后移动。连接正常，程序可以从数据库中检索字段，所以没有问题。
我在此处的代码位于标有“提交”的按钮上。当您单击此按钮时，它应该移动到数据库中的下一行并从该行中检索数据。检索到的数据应显示在“textarea”中。问题是当我点击下一步时它会显示最后一个结果？
class Abc extends JFrame implements ActionListener
{
JLabel l1, l2, l3, l4;
JButton b1, b2;
JTextArea j1, j2;
JCheckBox c1, c2, c3, c4;
ButtonGroup group = new ButtonGroup();
JPanel panel2;
Abc ()
{
j1 = new JTextArea();
j2 = new JTextArea();
c1 = new JCheckBox();
c2 = new JCheckBox();
c3 = new JCheckBox();
c4 = new JCheckBox();
j1.setEditable(false);
c1.setSelected(false);
c2.setSelected(false);
c3.setSelected(false);
c4.setSelected(false);
group.add(c1);
group.add(c2);
group.add(c3);
group.add(c4);
Connection conn = null;
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
conn = DriverManager.getConnection(
"jdbc:oracle:thin:@localhost:1521:xe", "system",
"java");
System.out.println("Dc is obtained");
}
catch (Exception e2)
{
System.out.println("conne" + e2.getMessage());
}
try
{
String sq = "select * from questionans";
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery(sq);
System.out
.println("------------------------------------------");
if (rs.next())
{
j1.setText(rs.getString(2));
c1.setText(rs.getString(3));
c2.setText(rs.getString(4));
c3.setText(rs.getString(5));
c4.setText(rs.getString(6));
}
System.out
.println("-------------------------------------------");
}
catch (Exception e1)
{
System.out.println("query" + e1.getMessage());
}
finally
{
try
{
conn.close();
}
catch (Exception e)
{
System.out.println("close conn" + e.getMessage());
}
}
b1 = new JButton("REGISTER");
b2 = new JButton("SUBMIT");
panel2 = new JPanel(new GridLayout(4, 1));
panel2.add(b1);
panel2.add(j1);
panel2.add(c1);
panel2.add(c2);
panel2.add(c3);
panel2.add(c4);
panel2.add(b2);
add(panel2, BorderLayout.CENTER);
b1.addActionListener(this);
b2.addActionListener(this);
setTitle("REGISTRATION");
}
public void actionPerformed (ActionEvent e)
{
Object source = e.getSource();
if (source == b1)
{
System.out.println("you pressed button b1");
}
else if (source == b2)
{
Connection conn = null;
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
conn = DriverManager.getConnection(
"jdbc:oracle:thin:@localhost:1521:xe", "system",
"java");
System.out.println("Dc is obtained");
}
catch (Exception e4)
{
System.out.println("conne" + e4.getMessage());
}
try
{
String sq = "select * from questionans";
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery(sq);
System.out
.println("------------------------------------------");
while (rs.next())
{
j1.setText(rs.getString(2));
c1.setText(rs.getString(3));
c2.setText(rs.getString(4));
c3.setText(rs.getString(5));
c4.setText(rs.getString(6));
}
System.out
.println("-------------------------------------------");
}
catch (Exception e3)
{
System.out.println("query" + e3.getMessage());
}
finally
{
try
{
conn.close();
}
catch (Exception e6)
{
System.out.println("close conn" + e6.getMessage());
}
}
String s2 = "";
if (c1.isSelected())
{
s2 = s2 + "" + c1.getText();
}
else if (c2.isSelected())
{
s2 = s2 + "" + c2.getText();
}
else if (c3.isSelected())
{
s2 = s2 + "" + c3.getText();
}
else if (c4.isSelected())
{
s2 = s2 + "" + c4.getText();
}
System.out.println("You clicked on " + s2);
}
}
}
class xyz
{
public static void main (String args[])
{
Abc a = new Abc();
a.setSize(1000, 1000);
a.setVisible(true);
a.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
【问题讨论】：