关于Java基于jdbc连接mysql数据库的实例分享

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class MySQLDemo {
  private Connection conn = null;
  private Statement stmt = null;
  private ResultSet rs = null;
  private String driverclass = "com.mysql.jdbc.Driver";
  private String url = "jdbc:mysql://localhost:3306/mydb";
  private String user = "root";
  private String password = "111111";
  public MySQLDemo() {
    try {
      Class.forName(driverclass).newInstance(); // 加载驱动程序
    } catch (InstantiationException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IllegalAccessException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (ClassNotFoundException e1) {
      // TODO Auto-generated catch block
      System.out.println("class not found");
    }
    try {
      conn = DriverManager.getConnection(url, user, password); // 获得Connection对象
    } catch (Exception e) {
      System.out.println("Connect failed!");
    }
  }
  public void selectMethod(String sql) {
    System.out.println("id title");
    try {
      stmt = conn.createStatement(); // 获得Statement对象
      rs = stmt.executeQuery(sql); // 执行SQL语句，并返回ResultSet类型的结果
      while (rs.next()) {
        String title = rs.getString("id");
        String name = rs.getString("name");
        System.out.println(title + " " + name);
      }
    } catch (SQLException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  public void closeDB() throws SQLException {
    if (rs != null)
      rs.close();
    if (stmt != null)
      stmt.close(); // 关闭Statement对象
    if (conn != null) // 关闭Connection对象
      conn.close();
  }
  public static void main(String args[]) {
    MySQLDemo demo = new MySQLDemo();
    demo.selectMethod("select * from test");
  }
}