java - Jackson JSON 和 Jayway JSON 路径

Question

我有一个如下的 json 字符串

    {
     "haserrors": 
                 {
                   "errornumber": "400",
                   "errors": [
                               {
                                 "nameofbusiness-error-1": "nameofbusiness must have a length greater than 1",
                                 "nameofbusiness-error-2": "legalname must have a length greater than 1",
                                 "nameofbusiness-error-3": "postaladdress must have a length greater than 1",
                                 "nameofbusiness-error-4": "city must have a length greater than 1",
                                 "nameofbusiness-error-5": "state must have a length greater than 1",
                                 "nameofbusiness-error-6": "pincode must have a length greater than 6, pincode must be numeric, pincode must be positive",
                                 "nameofbusiness-error-7": "fewwords must have a length greater than 1",
                                 "nameofbusiness-error-8": "lob must have a length greater than 1",
                                 "nameofbusiness-error-9": "step must be numeric, step must be positive"
                              }
                            ]
                }
    }

我需要提取“错误”下的所有节点和值。这是我当前的代码

    Configuration conf = Configuration.builder().jsonProvider(new JacksonJsonNodeJsonProvider())
            .options(Option.ALWAYS_RETURN_LIST, Option.SUPPRESS_EXCEPTIONS).build();
    ArrayNode jsonErrorMessageNodes = JsonPath.using(conf).parse(<<JSON STRING ABOVE>>).read("$..errors");

  for (Iterator<JsonNode> it = jsonErrorMessageNodes.elements() ; it.hasNext() ; ) {
            JsonNode node = it.next();
            String s = node.toString();
            System.out.println(node);
        }

如何获取节点名称？

Answer 1

以下代码...

Configuration conf = Configuration.builder().jsonProvider(new JacksonJsonNodeJsonProvider())
        .options(Option.ALWAYS_RETURN_LIST, Option.SUPPRESS_EXCEPTIONS).build();
ArrayNode jsonErrorMessageNodes = JsonPath.using(conf).parse(json).read("$..errors[*]");

for (Iterator<JsonNode> it = jsonErrorMessageNodes.elements() ; it.hasNext() ; ) {
    JsonNode node = it.next();
    for (Iterator<String> it1 = node.fieldNames(); it1.hasNext(); ) {
        final String s = it1.next();
        System.out.println(s);
    }
}

...将打印出:

nameofbusiness-error-1
nameofbusiness-error-2
nameofbusiness-error-3
nameofbusiness-error-4
nameofbusiness-error-5
nameofbusiness-error-6
nameofbusiness-error-7
nameofbusiness-error-8
nameofbusiness-error-9

此代码与您发布的代码之间的主要区别在于 JsonPath 表达式。您正在使用: $..errors ，它会产生如下内容:

[
   null,
   [
      {...}
   ],
   null
]

因此，为了找到您感兴趣的节点，需要遍历多个节点。相比之下，此表达式:仅返回 errors 数组，例如

[
   {...}
]