JSONPath入门之Snack3篇

Z时代
2024-01-10
分类：综合

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>3.1.5.3</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("$.store.book [0].title");
    System.out.println("
t1:" + t1);
    ONode t2 = n.select("$["store"]["book"][0]["title"]");
    System.out.println("
t2:" + t2);
    ONode t3 = n.select("$.store.book[*].author");
    System.out.println("
t3:" + t3);
    ONode t4 = n.select("$..author");
    System.out.println("
t4:" + t4);
    ONode t5 = n.select("$.store.*");
    System.out.println("
t5:" + t5);
    ONode t6 = n.select("$.store..price");
    System.out.println("
t6:" + t6);
    ONode t7 = n.select("$..book[2]");
    System.out.println("
t7:" + t7);
    ONode t8 =  n.select("$..book[-2]");
    System.out.println("
t8:" + t8);
    ONode t9 = n.select("$..book[0,1]");
    System.out.println("
t9:" + t9);
    ONode ta = n.select("$..book[:2]");
    System.out.println("
ta:" + ta);
    ONode tb = n.select("$..book[1:2]");
    System.out.println("
tb:" + tb);
    ONode tc = n.select("$..book[-2:]");
    System.out.println("
tc:" + tc);
    ONode td = n.select("$..book[2:]");
    System.out.println("
td:" + td);
    ONode te = n.select("$..book[?(@.isbn)]");
    System.out.println("
te:" + te);
    ONode tf = n.select("$.store.book[?(@.price < 10)]");
    System.out.println("
tf:" + tf);
    ONode tg = n.select("$..book[?(@.author =~ /.*REES/i)]");
    System.out.println("
tg:" + tg);
    ONode th = n.select("$..*");
    System.out.println("
th:" + th);
    ONode ti = n.select("$..book[?(@.price <= $.expensive)]");
    System.out.println("
ti:" + 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}]