conn.java~1~

教学管理系统的JAVA实现代码

package base.db;
import java.sql.*;

public class Conn
{
private static Connection con;
private Statement stmt;
private ResultSet rs;
private static String drivername="com.mysql.jdbc.Driver";
private static final String url="jdbc:mysql://localhost/test?user=root&password=yousufu";

public static synchronized Connection getCon() throws Exception{
    try{
        Class.forName(drivername);
        con=DriverManager.getConnection(url);
        return con;
    }
    catch(SQLException e){
    System.err.println(e.getMessage());
    throw e;
    }
  }
  public Statement getStmtread() {
          try {
              con = getCon();
              stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
              return stmt;
          } catch (Exception e) {
              System.err.println(e.getMessage());
              e.printStackTrace();
          }
          return null;
      }

      /**
       *output parameter: Data
       *input parameter:  SQL select sentence
       *modify time:      4/29/2006
       */
      public ResultSet getRs(String sql) {
          try {
              stmt = getStmtread();
              rs = stmt.executeQuery(sql);
              return rs;
          } catch (Exception e) {
              System.err.println(e.getMessage());
              e.printStackTrace();
          }
          return null;
      }

      /**
       *output parameter: not in order select in str SQL
       *modify time:      4/29/2006
       */
      public Statement getStmt() {
          try {
              con = getCon();
              stmt = con.createStatement();
              return stmt;
          } catch (Exception e) {
              System.err.println(e.getMessage());
              e.printStackTrace();
          }
          return null;
      }

      /**
       *method explain:   Close DataBase Connection
       *modify time:      4/29/2006
       */
      public synchronized void close() {
          try {
              if (rs != null) {
                  rs.close();
                  rs = null;
              }
          } catch (Exception e) {
              System.err.println(e.getMessage());
              e.printStackTrace();
          }
          try {
              if (stmt != null) {
                  stmt.close();
                  stmt = null;
              }
          } catch (Exception e) {
              System.err.println(e.getMessage());
              e.printStackTrace();
          }
          try {
              if (con != null) {
                  con.close();
                  con = null;
              }
          } catch (Exception e) {
              System.err.println(e.getMessage());
              e.printStackTrace();
          }
      }
}