数据库连接工具类

package com.pk.xjgs.util;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class DBConn {
    
    private static String jdbcDriver = "";
    
    private static String jdbcUrl = "";
    
    private static String jdbcUser = "";
    
    private static String jdbcPasswd = "";
    
    static{
        InputStream is = null;
        try {
            is = DBConn.class.getClassLoader().getResourceAsStream("database.properties");
            Properties p = new Properties();//对应properties文件的类
            p.load(is);//加载流 目的就是将流中的数据进行解析
//            System.out.println(p.getProperty("jdbcDriver"));
//            System.out.println(p.getProperty("jdbcUrl"));
//            System.out.println(p.getProperty("jdbcUser"));
//            System.out.println(p.getProperty("jdbcPasswd"));
            jdbcDriver = p.getProperty("jdbcDriver");
            jdbcUrl = p.getProperty("jdbcUrl");
            jdbcUser = p.getProperty("jdbcUser");
            jdbcPasswd = p.getProperty("jdbcPasswd");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(is != null){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    
    /*
     * 获取数据库指定的连接
     */
    public static Connection getConn(){
        Connection conn = null;
        try {
            Class.forName(jdbcDriver);
            conn = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPasswd);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }
    
    /*
     * 关闭数据库打开的对象  包括connection  statement  resultSet
     */
    public static void closeAll(Connection conn,Statement st,ResultSet rs){
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(st != null){
            try {
                st.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    public static void closeAll(Connection conn,PreparedStatement ps,ResultSet rs){
        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 closeConn(Connection conn){
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    public static void main(String[] args) {
        System.out.println(DBConn.getConn());
    }
}