python的多线程 ThreadPoolExecutor

from concurrent.futures import ThreadPoolExecutor,wait
import time
executor = ThreadPoolExecutor(max_workers = 2)

# 线程要执行的函数
def func(i):
    time.sleep(0.5)
    print(i)
    if i%2 == 1:

        return '奇数'
    else:
        return '偶数'

# 把线程加入线程字典
thread_list = [executor.submit(func, i) for i in range(5)]

# 取得线程执行结果  如果用result取结果，不用wait也会等所有线程执行完，如果没有使用到线程例如result()取结果,done()查看子线程是否已经执行完，那么不会等子线程执行完，如果要等子线程执行完，就要用wait
for thread in thread_list:
    print("线程名：",thread)
    print('thread.result()= :',thread.result())

# wait的功能：等待所有线程执行完
# print(wait(thread_list))
print('所有线程执行完 end......')

执行结果：

 

---

from concurrent.futures import ThreadPoolExecutor,wait
import time
executor = ThreadPoolExecutor(max_workers = 2)
# 线程要执行的函数
def func(i):
    time.sleep(0.5)
    if i%2 == 1:return {'status':1,'msg':'奇数'}
    else:return {'status':0,'msg':'偶数'}

# 用 map函数 更精简的取所有子线程执行结果：
for thread_exec_res in executor.map(func,list(range(10))):
    print('子线程执行结果',thread_exec_res)

执行结果：

---

list(map(......))将所有线程执行结果放在列表中：

print(list(executor.map(func,list(range(10)))))
↓↓

---

 设置超时时间：

def get_multithreading_res(approve_executor,fun_name,arg_list):
    for i in arg_list:
        all_task = [approve_executor.submit(fun_name, (i))]
        print('all_task:',all_task)
        for i in all_task:
            print('单个线程的结果',i.result(timeout=2))   # 可以通过result(timeout=2)设置线程超时时间
        print('执行完了')

第二种方法设置超时时间：

approve_executor = ThreadPoolExecutor(max_workers = 50)
def search_db(i):
    time.sleep(6)
    connection = pymysql.connect(host='localhost', port=3306,
                                 user='root',
                                 password='root1234',
                                 db='slb',
                                 charset='utf8',
                                 )
    with connection.cursor() as cursor:
        sql = "SELECT * FROM dyf_test_table1"
        cursor.execute(sql)
        data = cursor.fetchall()
        return {'hostname':i,'data':data}

def exec_multithreading(approve_executor, fun_name, arg_list):

    all_task = [approve_executor.submit(fun_name, i) for i in arg_list]
    for i in all_task:
        try:
            print(i.result(timeout=3))  # 设置超时时间为3s

        except concurrent.futures._base.TimeoutError as e:
            print('线程执行失败，原因：线程执行超时 请查找原因')
            continue #因超时异常后  后面的线程继续执行不会中断

        except Exception as e:
            print('线程执行异常:',e)


exec_multithreading(approve_executor, search_db, [1,2,3,4,5])