import pymysql from scrapy.exceptions import DropItem import time class ErshouchePipeline(object):     def __init__(self):         self.conn = pymysql.connect(             host = '127.0.0.1',             port = 3306,             user = 'root',             passwd = 'mlpythonlmoi',             db = 'ershouche',             charset = 'utf8'         )         self.cusor = self.conn.cursor(cursor=pymysql.cursors.DictCursor)         sql1 = "select 路由网址 from 二手车之家"         result = self.cusor.execute(sql1)#读取已经爬取的数据url         # print(result)         temp = self.cusor.fetchall()#返回查询到的所有记录         print('返回查询得到的记录：',temp)         self.url_list = []         for i in temp:             self.url_list.append(i['路由网址'])         print('存在的：',self.url_list)     def process_item(self, item, spider):         if item['car_url'] not in self.url_list:             sql = "insert into 二手车之家 values(Null,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)"             lst = (item['city'],item['trademark'],item['model'],item['colour'],item['price'],item['purpose'],                    item['vehicle_condition'],item['drive_mode'],item['Truck_kilometer'],item['car_license'],                    item['Stop_displacemen'],item['year_jian_due'],item['insurance_policy_matures'],item['assurance_due'],                    item['emission_standard'],item['guohu_number'],item['maintenance'],item['car_url'])             self.cusor.execute(sql,lst)             self.conn.commit()         else:             raise DropItem('该item数据库中已经存在！')         return item     def close_spider(self, spider):          self.cusor.close()          self.conn.close()#关闭连接          print("操作结束！")          print('结束时间：' + time.strftime('%Y-%m-%d %H:%M:%S', time.localtime()))