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.sqlserver.jdbc.SQLServerDriver";
	private static String dbUrl = "jdbc: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 { // 捕捉异常
			conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
			stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
					ResultSet.CONCUR_READ_ONLY);
			rs = stmt.executeQuery(sql);
		} catch (SQLException ex) {
			System.err.println(ex.getMessage()); // 输出异常信息
		}
		return rs; // 返回结果集对象
	}

	/*
	 * 功能:执行更新操作
	 */
	public int executeUpdate(String sql) {
		int result = 0; // 定义保存返回值的变量
		try { // 捕捉异常
			conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
			stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
					ResultSet.CONCUR_READ_ONLY);
			result = stmt.executeUpdate(sql); // 执行更新操作
		} catch (SQLException ex) {
			result = 0; // 将保存返回值的变量赋值为0
		}
		try {
			stmt.close();
		} catch (SQLException ex1) {
		}
		return result; // 返回保存返回值的变量
	}

	public int executeUpdate_id(String sql) {
		int result = 0; // 定义保存返回值的变量
		try { // 捕捉异常
			conn = getConnection(); // 调用getConnection()方法构造Connection对象的一个实例conn
			stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
					ResultSet.CONCUR_READ_ONLY);
			result = stmt.executeUpdate(sql); // 执行更新操作
			// 获取刚刚插入记录的自动编号
			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; // 返回刚刚插入的自动编号
	}

	/*
	 * 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
		}
	}

}