conndb.java

很强大有很多购物网站的基础功能

package com.tools;

import java.sql.*;
import java.io.*;
import java.util.*;

public class ConnDB {
  public Connection conn = null;
  public Statement stmt = null;
  public ResultSet rs = null;
  private static String propFileName = "/com/connDB.properties";  	//指定资源文件保存的位置
  private static Properties prop = new Properties();
  private static String dbClassName =
      "com.microsoft.jdbc.sqlserver.SQLServerDriver";
  private static String dbUrl =
      "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=db_shop";
  private static String dbUser = "sa";
  private static String dbPwd = "";
  
  public ConnDB(){
	    try {
	      InputStream in=getClass().getResourceAsStream(propFileName);
	      prop.load(in);									//通过输入流对象加载Properties文件
	      dbClassName = prop.getProperty("DB_CLASS_NAME");	//获取数据库驱动
	      dbUrl = prop.getProperty("DB_URL",dbUrl);
	      dbUser=prop.getProperty("DB_USER",dbUser);
	      dbPwd=prop.getProperty("DB_PWD",dbPwd);
	    }
	    catch (Exception e) {
	      e.printStackTrace();		//输出异常信息
	    }
	  }  
  public static Connection getConnection() {
    Connection conn = null;
    try {
      Class.forName(dbClassName).newInstance();
      conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd);
    }
    catch (Exception ee) {
      ee.printStackTrace();
    }
    if (conn == null) {
      System.err.println(
          "警告: DbConnectionManager.getConnection() 获得数据库链接失败.\r\n\r\n链接类型:" +
          dbClassName + "\r\n链接位置:" + dbUrl + "\r\n用户/密码" + dbUser + "/" +
          dbPwd);
    }
    return conn;
  }

  /*
   *功能：执行查询语句
   */
  public ResultSet executeQuery(String sql) {
    try {
      conn = getConnection();
      stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                  ResultSet.CONCUR_READ_ONLY);
      rs = stmt.executeQuery(sql);
    }
    catch (SQLException ex) {
      System.err.println(ex.getMessage());
    }
    return rs;
  }

  /*
   *功能:执行更新操作
   */
  public int executeUpdate(String sql) {
    int result = 0;
    try {
      conn = getConnection();
      stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                  ResultSet.CONCUR_READ_ONLY);
      result = stmt.executeUpdate(sql);
    }catch (SQLException ex) {
      result = 0;
    }
    try {
      stmt.close();
    }catch (SQLException ex1) {
    }
    return result;
  }

  public int executeUpdate_id(String sql) {
    int result = 0;
    try {
      conn = getConnection();
      stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                                  ResultSet.CONCUR_READ_ONLY);
      result = stmt.executeUpdate(sql);
      String ID = "select @@IDENTITY as id";
      rs = stmt.executeQuery(ID);
      if (rs.next()) {
        int autoID = rs.getInt("id");
        result = autoID;
      }
    }
    catch (SQLException ex) {
      result = 0;
    }
    return result;
  }

  /*
   *功能:关闭数据库的连接
   */
  public void close() {
		try {							//捕捉异常
			if (rs != null) {				//当ResultSet对象的实例rs不为空时
				rs.close();					//关闭ResultSet对象
			}
			if (stmt != null) {				//当Statement对象的实例stmt不为空时
				stmt.close();				//关闭Statement对象
			}
			if (conn != null) {				//当Connection对象的实例conn不为空时
				conn.close();				//关闭Connection对象
			}
		} catch (Exception e) {
			e.printStackTrace(System.err);	//输出异常信息
		}
	} 


}