package com.huang;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

public class DBUtil {

	private static final String driver = "com.mysql.jdbc.Driver";

	private static final String url = "jdbc:mysql://localhost:3306/test";

	private static final String username = "root";

	private static final String password = "root";

	public Connection conn = null;

	public PreparedStatement ps = null;

	public ResultSet rs = null;

	public Connection getConnection() {

		try {

			Class.forName(driver);

			return DriverManager.getConnection(url, username, password);

		} catch (Exception e) {

			System.out.println("get driver or connection error!");

			e.printStackTrace();

		}

		return null;

	}

	/**

	 * 通用查询方法

	 * @param sql

	 * @param obj

	 * @return

	 */

	public ResultSet query(String sql, Object[] obj) {

		conn = getConnection();

		if(conn == null) {

			return null;

		}

		try {

			ps = conn.prepareStatement(sql);

			if(obj!=null && obj.length>0) {

				for (int i = 0; i < obj.length; i++) {

					ps.setObject(i+1, obj[i]);

				}

			}

			return ps.executeQuery();

		} catch (Exception e) {

		}

		return null;

	}

	public void close() {

		if(rs!=null) {

			try {

				rs.close();

			} catch (SQLException e) {

				e.printStackTrace();

			}

		}

		if(ps!=null) {

			try {

				ps.close();

			} catch (SQLException e) {

				e.printStackTrace();

			}

		}

		if(conn!=null) {

			try {

				conn.close();

			} catch (SQLException e) {

				e.printStackTrace();

			}

		}

	}

	public static void main(String[] args) throws Exception {

		DBUtil dbUtil = new DBUtil();

		dbUtil.rs = dbUtil.query("select * from user_info where id = ?", new Object[] {"1"});

		while(dbUtil.rs.next()) {

			System.out.println(dbUtil.rs.getString(1) + "--" + dbUtil.rs.getString(2));

		}

		dbUtil.close();

	}

}