Python中使用with优美的释放资源

Python中有类似jdk7中的资源释放语法糖，可以优美的释放资源流程

import mysql.connector as conn

class DBUtil:

    def __init__(self, host, user, passwd, database):
        self.db = conn.connect(host=host, user=user, passwd=passwd, database=database)

    # with定义完成
    def __enter__(self):
        return self.db.cursor()

    # with内代码执行完成后执行
    def __exit__(self, exc_type, exc_val, exc_tb):
        self.db.commit()
        self.db.disconnect()


if __name__ == "__main__":

    with DBUtil("localhost", "root", "root", "test") as cur:
        sql = "select * from user_name"
        cur.execute(sql)
        for item in cur.fetchall():
            print(item)