JDBC连接问题
我正在使用NetBeans IDE(6.8)。我有一个DB类:JDBC连接问题,jdbc,Jdbc,我正在使用NetBeans IDE(6.8)。我有一个DB类: package garits; import java.io.Serializable; import java.sql.*; import java.util.Properties; public class DB implements Serializable{ private static final long serialVersionUID = 1L; String dbURL = "jdbc:mysql:///
package garits;
import java.io.Serializable;
import java.sql.*;
import java.util.Properties;
public class DB implements Serializable{
private static final long serialVersionUID = 1L;
String dbURL = "jdbc:mysql:///team_project";
String user = "root";
String pwd = "arsenal";
String dbDriver = "com.mysql.jdbc.Driver";
private Connection dbCon;
private ResultSet r;
private Statement s;
public DB()
{}
public boolean connect() throws ClassNotFoundException,SQLException{
Class.forName(dbDriver);
Properties props = new Properties();
props.put(user, "root");
props.put(pwd, "arsenal");
props.put("charSet", "UTF-8");
props.put("lc_ctype", "UTF-8");
dbCon = DriverManager.getConnection(dbURL,props);
//dbCon = DriverManager.getConnection(dbURL,user,pwd);
return true;
}
public void close() throws SQLException{
dbCon.close();
if(r!=null)
r.close();
if(s!=null)
s.close();
}
public ResultSet execSQL(String sql) throws SQLException{
s = dbCon.createStatement();
r = s.executeQuery(sql);
return (r == null) ? null : r;
}
public int updateSQL(String sql) throws SQLException{
s = dbCon.createStatement();
int r = s.executeUpdate(sql);
return (r == 0) ? 0 : r;
}
public int updateSQL(String sql, String getID) throws SQLException{
s = dbCon.createStatement();
int autoIncValue = -1;
s.executeUpdate(sql, Statement.RETURN_GENERATED_KEYS);
ResultSet rs = s.getGeneratedKeys();
if (rs.next()) {
autoIncValue = rs.getInt(1);
}
return autoIncValue;
}
}
jar文件是我的库,但每当我尝试连接时:
private void loginButtonActionPerformed(java.awt.event.ActionEvent evt) {
String result ="";
DB db = new DB();
try{
db.connect();
String query = "Select Role From User_Account Where Username=jTextField1.getText()AND Where Password=jTextField2.getText(); ";
ResultSet rs=db.execSQL(query);
while(rs.next())
{
result = rs.getString("Role");
}
if(result.equals(""))
{
JOptionPane.showMessageDialog(loginButton,"Access denied","Error Message",JOptionPane.ERROR_MESSAGE);
}
else if(result.equals("Administrator"))
{
MainPage_Admin admin = new MainPage_Admin();
}
}
catch(Exception e)
{
System.out.println("An error has occurred");
}
}
我得到一个错误(异常被捕获)-数据库的名称是“team_project”,密码是“arsenal”-任何想法都值得赞赏。我是JDBC新手。第一步:至少在catch块中使用,从异常中获取一些信息。否则您只能猜测。MySQL数据库url连接属性错误
jdbc:mysql://localhost:3306/<your database name>
修改并执行程序,更好地在try/catch块中处理异常,而不是抛出异常。I get:java.sql.SQLException:Access denied for user'@'localhost'(使用密码:否)为什么拒绝访问,谢谢。@eli:因为您没有正确设置用户/密码属性。检查将
user
和pwd
放入Properties
的两行代码:这是错误的。此JDBC代码中还有一个主要问题:它正在泄漏资源。在try finally
块中,在尽可能短的范围内获取并关闭它们。示例如下:
jdbc:mysql:///team_project