dao.java~16~

北大青鸟几次机试的试题

package fly;

import java.sql.*;
import java.util.Vector;

public class DAO {
    java.sql.Connection con;
    java.sql.PreparedStatement pst;
    java.sql.ResultSet rs;
    public DAO() {
        try {
            //加载驱动
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }
        try {
            jbInit();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    public void getcon() {
        //一个连接的方法
        try {
            con = java.sql.DriverManager.getConnection(
                    "jdbc:microsoft:sqlserver://localhost:1433;databasename=flyly;",
                    "sa", "");
        } catch (SQLException ex) {
            ex.printStackTrace();
        }

    }
//一个判断输入是否区分大小写的方法
    public String[] verdict(bean a) {
      getcon();
      String[] v = new String[2];
      try {
          pst = con.prepareStatement("select leavecity,destination from ticketinfo where (leavecity=? and destination=?)");
          pst.setString(1, a.getLeavecity());
          pst.setString(2, a.getDestination());
          rs = pst.executeQuery();
      } catch (SQLException ex) {
          ex.printStackTrace();
      }
      try {
          if (rs.next()) {
              v[0]=rs.getString(1);
              v[1]=rs.getString(2);
          }
      } catch (SQLException ex1) {
          ex1.printStackTrace();
      } finally {
          try {
              rs.close();
              pst.close();
              con.close();

          } catch (SQLException ex2) {
              ex2.printStackTrace();
          }

      }

      return v;
  }


    //一个查询的方法
    public Vector select(bean a) {
        getcon();
        Vector v = new Vector();
        try {
            pst = con.prepareStatement("select flightno from ticketinfo where (leavecity=? and destination=? and econum>=?)");
            pst.setString(1, a.getLeavecity());
            pst.setString(2, a.getDestination());
            pst.setInt(3, Integer.parseInt(a.getEconum()));
            rs = pst.executeQuery();
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
        try {
            while (rs.next()) {
                int i=0;
                if(i==0){
                 v.addElement(rs.getString(1));
                }else{
                v.addElement("/n"+rs.getString(1));
                }
               i++;
            }
        } catch (SQLException ex1) {
            ex1.printStackTrace();
        } finally {
            try {
                rs.close();
                pst.close();
                con.close();

            } catch (SQLException ex2) {
                ex2.printStackTrace();
            }

        }

        return v;
    }

    private void jbInit() throws Exception {
    }

}