编辑pipelines.py，添加自定义pipelines类：

class MySQLPipeline(object):

    @classmethod
    def from_crawler(cls, crawler):
        # 从项目的配置文件中读取相应的参数
        cls.MYSQL_DB_NAME = crawler.settings.get("MYSQL_DB_NAME", 'scrapy_default')
        cls.HOST = crawler.settings.get("MYSQL_HOST", 'localhost')
        cls.PORT = crawler.settings.get("MYSQL_PORT", 3306)
        cls.USER = crawler.settings.get("MYSQL_USER", 'root')
        cls.PASSWD = crawler.settings.get("MYSQL_PASSWORD", 'new.1234')
        return cls()

    def open_spider(self, spider):
        self.dbpool = adbapi.ConnectionPool('pymysql', host=self.HOST, port=self.PORT, user=self.USER, passwd=self.PASSWD, db=self.MYSQL_DB_NAME, charset='utf8')

    def close_spider(self, spider):
        self.dbpool.close()

    def process_item(self, item, spider):
        self.dbpool.runInteraction(self.insert_db, item)

        return item

    def insert_db(self, tx, item):
        values = (
            item['upc'],
            item['name'],
            item['price'],
            item['review_rating'],
            item['review_num'],
            item['stock'],
        )
        sql = 'INSERT INTO books VALUES (%s,%s,%s,%s,%s,%s)'
        tx.execute(sql, values)

接着在settings.py中写入相关配置参数，添加至item_pipelines中：

MYSQL_DB_NAME = 'scrapy_db'
MYSQL_HOST = 'localhost'
MYSQL_PORT = 3306
MYSQL_USER = 'root'
MYSQL_PASSWORD = 'new.1234'
# 
ITEM_PIPELINES = {
    'toscrape_book.pipelines.MySQLPipeline': 400,
}