[英]How to get a String from h2 database (Java, DBUtil)
这是DBUtil的代码
public class DBUtil {
static Connection conn = null;
public static Connection getConnected() {
try {
Class.forName("org.h2.Driver");
conn = DriverManager.getConnection("jdbc:h2:tcp://localhost/~/test", "sa", "");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}//end method
}//end DBUtil
这是我尝试使用的方法中的代码:
private class SearchForEdit implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e) {
String clientNumber = tfieldMiniSearchNumber.getText();
int number;
conn = DBUtil.getConnected();
if(conn == null) return;
String names=null, address=null;
String sql ="select names from clients where client_number = ?;";
String sql2 ="select address from clients where client_number = ?;";
try {
state = conn.prepareStatement(sql);
state.setInt(1, number);
state.execute();
state = conn.prepareStatement(sql2);
state.setInt(1, number);
state.execute();
labelWarning.setForeground(new Color(22, 205, 5));
labelWarning.setText("<html>TEXT SUCCESS</html>");
//names = select names from clients where client_number = number;
//address = select address from clients where client_number = number;
//if(names!=null && address!=null)
//tfieldEditClientNumber to be number
tfieldEditClientNumber.setText(""+number);
//tfieldEditNames to be names, where names = select names from clients where client_number = number;
//tfieldEditAddressда to be address, where address = select address from clients where client_number = number;
} catch (SQLException e1) {
labelWarning.setForeground(Color.RED);
labelWarning.setText("<html>Try again later</html>");
e1.printStackTrace();
}
}
}//end
我想从数据库中获取NAME列的值,然后放入字符串名称中。 然后地址相同。 我只知道如何执行语句。 任何帮助都非常感激!
您需要将查询的结果存储在ResultSet
,然后在该ResultSet
进行迭代。 您可以在遍历变量时将ResultSet
的值分配给变量。
以下代码是对 ResultSet
进行迭代的示例 ,如我在下面的评论中所述。
while (rs.next()) {
// ResultSet columns: 1 = UserName 2 = FirstName 3 = LastName 4 = Organization
userInfo[0] = rs.getString(1); // assign UserName result to variable
userInfo[1] = rs.getString(2); // assign First_Name result to variable
userInfo[2] = rs.getString(3); // assign Last_Name result to variable
userInfo[3] = rs.getString(4); // assign Organization result to variable
}
如果没有要迭代的ResultSet
行,则while循环将结束。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.