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所以我连接到数据库,我想从表投票的奶牛数字显示它在条形图,但我得到错误“Java。 sql.SQLException:在结果的开始时设置”,但我已经和rs.next可有一个人帮我请java.sql.SQLException:结果集开始之前已经有rs.next
conn = DbCon.ConnectDb();
String sql = "SELECT * FROM votes";
try
{
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
String cows = rs.getString("cows");
if (rs.next())
{
int cowss = Integer.parseInt(cows);
DefaultCategoryDataset dataset=new DefaultCategoryDataset();
dataset.setValue(cowss ,"Votes", "Cows");
dataset.setValue(20 ,"Votes", "Pigs");
dataset.setValue(20 ,"Votes", "Dogs");
dataset.setValue(50 ,"Votes", "Donkeys");
JFreeChart chart = ChartFactory.createBarChart("Results", "", "Votes", dataset, PlotOrientation.VERTICAL , false, true, true);
ChartFrame frame = new ChartFrame("Results", chart);
frame.setVisible(true);
frame.setSize(450,350);
frame.setLocationRelativeTo(null);
frame.setResizable(false);
}
}
catch(Exception e)
{
JOptionPane.showMessageDialog(null, e);
}
哇:D谢谢你......我是java..ty的新手^^ –