Python json.loads不起作用

Question

我一直在试图弄清楚如何在Python中加载JSON对象.

   def do_POST(self):
    length = int(self.headers['Content-Length'])
    decData = str(self.rfile.read(length))
    print decData, type(decData)
    "{'name' : 'journal2'}" <type 'str'>
    postData = json.loads(decData)
    print postData, type(postData)
    #{'name' : 'journal2'} <type 'unicode'>
    postData = json.loads(postData)
    print postData, type(postData)
    # Error: Expecting property name enclosed in double quotes

我哪里错了？

错误代码(JScript):

var data = "{'name':'journal2'}";
var http_request = new XMLHttpRequest();
http_request.open( "post", url, true );
http_request.setRequestHeader('Content-Type', 'application/json');
http_request.send(data);

True Code(JScript):

var data = '{"name":"journal2"}';
var http_request = new XMLHttpRequest();
http_request.open( "post", url, true );
http_request.setRequestHeader('Content-Type', 'application/json');
http_request.send(JSON.stringify(data));

真正的代码(Python):

   def do_POST(self):
    length = int(self.headers['Content-Length'])
    decData = self.rfile.read(length)
    postData = json.loads(decData)
    postData = json.loads(postData)

Answer 1

您的JSON数据用引号括起来,使其成为JSON字符串,并且该字符串中包含的数据不是 JSON.

打印repr(decData)而不是,你会得到:

'"{\'name\' : \'journal2\'}"'

并且JSON库正确地将其解释为具有文字内容的一个字符串{'name' : 'journal2'}.如果剥离外引号,则包含的字符不是有效的JSON,因为JSON字符串必须始终用双引号括起来.

对于所有json模块而言,decData也可以包含"This is not JSON"并且postData已经设置为u'This is not JSON'.

>>> import json
>>> decData = '''"{'name' : 'journal2'}"'''
>>> json.loads(decData)
u"{'name' : 'journal2'}"
>>> json.loads(json.loads(decData))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 326, in loads
    return _default_decoder.decode(s)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 366, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 382, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 1 (char 1)

修复产生此字符串的任何内容,您的视图很好,这是输入被破坏.

Answer 2

要解决错误“期望属性名称包含在双引号中”，您可以执行以下操作：

import json
data = "{'name' : 'journal2'}"
json.loads(json.dumps(data))