豆芽丝 JSONPath的使用
某些情况下，我们需要查询json对象特定属性值下的结果，通过JSONPath可以很方便我们查询。
关于
JsonPath的介绍，http://goessner.net/articles/JsonPath/，JsonPath对于JSON来说相当于XPATH对于XML。这是一个简单的从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,Java,Python和PHP等。
这里我要演示的是 javascript 实现版本，使用的 jsonpath 类库来自 GitHub 上 jQuery-JSONPath ，注意该类库依赖于 jQuery 。
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>JSONPath演示</title>
<script type="text/javascript" src="jquery-1.8.3.min.js"></script>
<script type="text/javascript" src="jsonpath.jquery.min.js"></script>
</head>
<body>
<script type="text/javascript">
var json = {
"store": {
"book": [
{ "category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": 8.95
},
{ "category": "fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": 12.99
},
{ "category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": 8.99
},
{ "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
}
}
}
var path = $.JSONPath({data: json, keepHistory: false});
var authors = path.query('$.store.book[*].author'); // returns all authors
var cheapier_books = path.query('$..book[?(@.price<10)]'); // filter all books cheapier than 10
var isbn_books = path.query('$..book[?(@.isbn)]'); // filter all books with isbn number
var reference_books = path.query('$..book[?(@.category == "reference")]'); // filter 'reference' books
console.log(authors);
console.log(cheapier_books);
console.log(isbn_books);
console.log(reference_books);
</script>
</body>
</html>