老师这个错误是什么呀

Exception in thread "main" java.lang.NullPointerException

package com.imooc.jdbc.sample;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.imooc.jdbc.common.DbUtils;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Date;
import java.util.Properties;

/*
 * Druid连接池配置与使用
 *
 * */
public class DruidSample {
public static void main(String[] args) {
//        1.加载属性文件
        Properties properties = new Properties();//利用这个对象来保存我们的配置信息
        String propertyFile = DruidSample.class.getResource("druid-config.properties").getPath();
        try {
            propertyFile = new URLDecoder().decode(propertyFile, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
//编译的时候会将空格转换为%20
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        try {

            properties.load(new FileInputStream(propertyFile));
//        2.获取DataSource数据源对象
            DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);
//        3.创建数据库的连接
            conn = dataSource.getConnection();
            pstmt = conn.prepareStatement("select * from goods limit 0,10");
            rs = pstmt.executeQuery();
            while (rs.next()) {
int id = rs.getInt("id");
                String ename = rs.getString("ename");
                float price = rs.getFloat("price");
                String desp = rs.getString("desp");
                Date sj = rs.getDate("hiredate");
                System.out.println(id + "-" + ename + "-" + price + "-" + desp + "-" + sj);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            DbUtils.closeConnection(conn, pstmt, rs);
        }
    }

}