JSONPath入门之Snack3篇

Snack3 for java

一个微型JSON框架

基于jdk8，60kb。有序列化反序列化、解析和转换、支持 Json path 查询。

<dependency>
  <groupId>org.noear</groupId>
  <artifactId>snack3</artifactId>
  <version>3.1.5.9</version>
</dependency>

Snack3 借签了 Javascript 所有变量由 var 申明，及 Xml dom 一切都是 Node 的设计。其下一切数据都以ONode表示，ONode也即 One node 之意，代表任何类型，也可以转换为任何类型。

• 强调文档树的操控和构建能力
• 做为中间媒体，方便不同格式互转
• 高性能Json path查询（兼容性和性能很赞）
• 支持序列化、反序列化

今天用它来试一下JSONPath入门

一、JSONPath语法介绍

• 字符串使用单引号，例：['name']
• 过滤操作用空隔号隔开，例：[?(@.type == 1)]

支持操作	说明
$	表示根元素
@	当前节点（做为过滤表达式的谓词使用）
*	通用配配符，可以表示一个名字或数字。
..	深层扫描。 可以理解为递归搜索。
.<name>	表示一个子节点
['<name>' (, '<name>')]	表示一个或多个子节点
[<number> (, <number>)]	表示一个或多个数组下标（负号为倒数）
[start:end]	数组片段，区间为[start,end),不包含end（负号为倒数）
[?(<expression>)]	过滤表达式。 表达式结果必须是一个布尔值。

支持过滤操作符	说明
==	left等于right（注意1不等于'1'）
!=	不等于
<	小于
<=	小于等于
>	大于
>=	大于等于
=~	匹配正则表达式[?(@.name =~ /foo.*?/i)]
in	左边存在于右边 [?(@.size in ['S', 'M'])]
nin	左边不存在于右边

支持尾部函数	说明
min()	计算数字数组的最小值
max()	计算数字数组的最大值
avg()	计算数字数组的平均值
sum()	计算数字数组的汇总值（新加的）

二、准备JSON数据

{
	"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
		}
	},
	"expensive": 10
}

三、演示代码

@Test
public void demo1(){
    final String 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}},\"expensive\":10}";

    ONode n = ONode.load(json);

    ONode t1 = n.select("$.store.book [0].title");
    System.out.println("\nt1:" + t1);

    ONode t2 = n.select("$['store']['book'][0]['title']");
    System.out.println("\nt2:" + t2);

    ONode t3 = n.select("$.store.book[*].author");
    System.out.println("\nt3:" + t3);

    ONode t4 = n.select("$..author");
    System.out.println("\nt4:" + t4);

    ONode t5 = n.select("$.store.*");
    System.out.println("\nt5:" + t5);

    ONode t6 = n.select("$.store..price");
    System.out.println("\nt6:" + t6);

    ONode t7 = n.select("$..book[2]");
    System.out.println("\nt7:" + t7);

    ONode t8 =  n.select("$..book[-2]");
    System.out.println("\nt8:" + t8);

    ONode t9 = n.select("$..book[0,1]");
    System.out.println("\nt9:" + t9);

    ONode ta = n.select("$..book[:2]");
    System.out.println("\nta:" + ta);

    ONode tb = n.select("$..book[1:2]");
    System.out.println("\ntb:" + tb);

    ONode tc = n.select("$..book[-2:]");
    System.out.println("\ntc:" + tc);

    ONode td = n.select("$..book[2:]");
    System.out.println("\ntd:" + td);

    ONode te = n.select("$..book[?(@.isbn)]");
    System.out.println("\nte:" + te);

    ONode tf = n.select("$.store.book[?(@.price < 10)]");
    System.out.println("\ntf:" + tf);

    ONode tg = n.select("$..book[?(@.author =~ /.*REES/i)]");
    System.out.println("\ntg:" + tg);

    ONode th = n.select("$..*");
    System.out.println("\nth:" + th);

    ONode ti = n.select("$..book[?(@.price <= $.expensive)]");
    System.out.println("\nti:" + ti);
}

四、控制台输出

t1:"Sayings of the Century"

t2:"Sayings of the Century"

t3:["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]

t4:["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]

t5:[[{"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}],{"color":"red","price":19.95}]

t6:[8.95,12.99,8.99,22.99,19.95]

t7:[{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99}]

t8:[{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99}]

t9:[{"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}]

ta:[{"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}]

tb:[{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99}]

tc:[{"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}]

td:[{"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}]

te:[{"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}]

tf:[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99}]

tg:[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95}]

th:[{"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}},[{"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}],{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},"reference","Nigel Rees","Sayings of the Century",8.95,{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},"fiction","Evelyn Waugh","Sword of Honour",12.99,{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},"fiction","Herman Melville","Moby Dick","0-553-21311-3",8.99,{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99},"fiction","J. R. R. Tolkien","The Lord of the Rings","0-395-19395-8",22.99,{"color":"red","price":19.95},"red",19.95,10]

ti:[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99}]