dbm.java

网上订餐系统的源码

package com.tx.common;

import java.sql.*;

//数据库访问统一API
public class DBM {
  private Connection con;
  public DBM() {
    openConn();
  }

  //打开数据库连接
  private void openConn() {
    try {
      if (con == null) {
        Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
        con = DriverManager.getConnection(
            "jdbc:sqlserver://localhost:1433;dataBaseName=books",
            "sa", "");
      }
    }
    catch (SQLException ex) {
      ex.printStackTrace();
    }
    catch (ClassNotFoundException ex) {
      ex.printStackTrace();
    }
  }

  //关闭数据库连接
  public void closeConn() {
    try {
      if (con != null && !con.isClosed()) {
        con.close();
        con = null;
      }
    }
    catch (SQLException ex) {
      ex.printStackTrace();
    }

  }

  //执行增加,删除,修改
  public int executeSQL(String sql) {
    int result = 0;
    openConn();
    try {
      Statement stmt = con.createStatement();
      result = stmt.executeUpdate(sql);
    }
    catch (SQLException ex) {
      ex.printStackTrace();
    }
    finally {
      closeConn();
    }
    return result;
  }

  //执行查询
  public ResultSet executeQuery(String selectSql) {
    ResultSet rs = null;
    openConn();
    try {
      Statement stmt = con.createStatement();
      rs = stmt.executeQuery(selectSql);
    }
    catch (SQLException ex) {
      ex.printStackTrace();
    }
    return rs;
  }

}