java读取MySQL数据库
publicvoidconnectDatabase(){driver="com.mysql.jdbc.Driver";url="jdbc:mysql://localhos...
public void connectDatabase(){
driver = "com.mysql.jdbc.Driver";
url = "jdbc:mysql://localhost:3306/library";
user = "root";
password = "123456";
try{
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, user, password);
statement = conn.createStatement();
sql = "select * from user where id = '" + licenseid.getText() + "' and password = '" + pwd.getText() + "'";
ResultSet rs = statement.executeQuery(sql);
if(!rs.isBeforeFirst()){
JOptionPane.showMessageDialog(frame, "Wrong password!");
}
else
{
String value = rs.getString("name");
JOptionPane.showMessageDialog(frame, rs.getString(3) + "Welcome to library!");
}
}catch(ClassNotFoundException e) {
JOptionPane.showMessageDialog(frame, "Sorry,can`t find the Driver!");
}catch(SQLException e) {
e.printStackTrace();
}catch(Exception e) {
e.printStackTrace();
}
}
String value = rs.getString("name");这一步读取数据库中对应用户的名字(属性定义为char[30]),但是程序运行到这一行后,就会抓到错误
catch(SQLException e) {
e.printStackTrace();
哪里错了?
改怎么正确读取数据库中的数据? 展开
driver = "com.mysql.jdbc.Driver";
url = "jdbc:mysql://localhost:3306/library";
user = "root";
password = "123456";
try{
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, user, password);
statement = conn.createStatement();
sql = "select * from user where id = '" + licenseid.getText() + "' and password = '" + pwd.getText() + "'";
ResultSet rs = statement.executeQuery(sql);
if(!rs.isBeforeFirst()){
JOptionPane.showMessageDialog(frame, "Wrong password!");
}
else
{
String value = rs.getString("name");
JOptionPane.showMessageDialog(frame, rs.getString(3) + "Welcome to library!");
}
}catch(ClassNotFoundException e) {
JOptionPane.showMessageDialog(frame, "Sorry,can`t find the Driver!");
}catch(SQLException e) {
e.printStackTrace();
}catch(Exception e) {
e.printStackTrace();
}
}
String value = rs.getString("name");这一步读取数据库中对应用户的名字(属性定义为char[30]),但是程序运行到这一行后,就会抓到错误
catch(SQLException e) {
e.printStackTrace();
哪里错了?
改怎么正确读取数据库中的数据? 展开
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