【Python】Json读写操作_JsonPath用法详解

1. 介绍

JSONPath是一种信息抽取类库，是从JSON文档中抽取指定信息的工具，提供多种语言实现版本，包括Javascript、Python、PHP和Java。

• JSONPath的安装方法如下：pip install jsonpath

JSONPath语法和XPATH语法对比，JSON结构清晰，可读性高，复杂度低，非常容易匹配。JSONPath的语法与Xpath类似，如下表所示为JSONPath与XPath语法对比：

2. 代码示例

bookJson = {
  "store": {
    "book":[
      { "category": "reference",
        "author": "Nigel Rees",
        "title": "Sayings of the Century",
        "price": 8.95
      },
      { "category": "fiction",
        "author": "J. R. R. Tolkien",
        "title": "The Lord of the Rings",
        "isbn": "0-395-19395-8",
        "price": 22.99
      }
    ],
    "bicycle": {
      "color": "red",
      "price": 19.95
    }
  }
}

变量bookJson中已经包含了这段JSON字符串，可通过以下代码反序列化得到JSON对象：

books=json.loads(bookJson)

1）查看store下的bicycle的color属性：

checkurl = "$.store.bicycel.color"
print(jsonpath.jsonpath(books, checkurl))
# 输出：['red']

2）输出book节点中包含的所有对象：

checkurl = "$.store.book[*]"
object_list=jsonpath.jsonpath(books, checkurl)
print(object_list)

3）输出book节点的第一个对象：

checkurl = "$.store.book[0]"
obj = jsonpath.jsonpath(books, checkurl)
print(obj)
# 输出: ['category': 'reference', 'author': 'Nigel Rees', 'title': 'Sayings of the Century', 'price': 8.95}]

4）输出book节点中所有对象对应的属性title值：

checkurl = "$.store.book[*].title"
titles = jsonpath.jsonpath(books, checkurl)
print(titles)
# 输出: ['Sayings of the Century', 'The Lord of the Rings']

5）输出book节点中category为fiction的所有对象：

checkurl = "$.store.book[?(@.category=='fiction')]”
books=jsonpath.jsonpath(books, checkurl)
print(books)
# 输出:[{'category': 'fiction', 'author': 'J. R. R. Tolkien', 'title': 'The Lordof the Rings', 'isbn': '0-395-19395-8'， 'price': 22.99}]

6）输出book节点中所有价格小于10的对象：

checkurl="$.store.book[?(@.price<10)]"
books = jsonpath.jsonpath(books, checkurl)
print(books)
# 输出: [{'category': 'reference', 'author': 'Nigel Rees', 'title':'Sayings of the Century', 'price': 8.95}]

7）输出book节点中所有含有isb的对象：

checkurl = "$.store.book[?(@.isb)]"
books = jsonpath.jsonpath(books，checkurl)
print(books)
# 输出: [{'category': 'fiction', 'author': 'J. R. R. Tolkien', 'title': 'The Lord of the Rings', 'isbn': '0-395-19395-8'， 'price': 22.99}]

3. 参考

【1】https://blog.csdn.net/fallenjency/article/details/123276600