java连接oracle数据库简单实例

package cn.com.login.dao;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;public class LoginDao {    public String getUserName(String userCode){            Connection con = null;            PreparedStatement pre = null;            ResultSet result = null;            String userName = "";            try {                        Class.forName("oracle.jdbc.driver.OracleDriver"); //加载Oracle驱动程序                        System.out.println("开始尝试连接数据库！");                        String url = "jdbc:oracle:" + "thin:@10.10.19.19:1521:db123";                        String user = "system";                        String password = "scc123456";                        con = DriverManager.getConnection(url, user, password);                        System.out.println("连接成功");                        String sql = "select userName from web01_test where userCode = ?";                        pre = con.prepareStatement(sql);                        pre.setString(1, userCode);                        result = pre.executeQuery();                                                while (result.next()) {                                userName = result.getString("userName");                        }                                        } catch (Exception e) {                        e.printStackTrace();                } finally {                    try {                            if (result != null) {                                    result.close();                            }                            if (pre != null) {                                    pre.close();                            }                            if (con != null) {                                    con.close();                            }                                                        } catch (Exception e2) {                                e2.printStackTrace();                        }            }            return userName;    }}