Python
import json
def is_json(myjson):
 try:
  json_object = json.loads(myjson)
 except ValueError, e:
  return False
 return True

Python
print is_json("{}")             #prints True
print is_json("{asdf}")           #prints False
print is_json('{ "age":100}')        #prints True
print is_json("{'age':100 }")        #prints False
print is_json("{\"age\":100 }")       #prints True
print is_json('{"age":100 }')        #prints True
print is_json('{"foo":[5,6.8],"foo":"bar"}') #prints True

# -*- coding=utf-8 -*-
import json
def check_json_format(raw_msg):
  """
  用于判断一个字符串是否符合Json格式
  :param self:
  :return:
  """
  if isinstance(raw_msg, str):    # 首先判断变量是否为字符串
    try:
      json.loads(raw_msg, encoding='utf-8')
    except ValueError:
      return False
    return True
  else:
    return False
if __name__ == "__main__":
  print check_json_format("""{"a":1}""")
  print check_json_format("""{'a':1}""")
  print check_json_format({'a': 1})
  print check_json_format(100)

True
False
False
False