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。


  org.noear
  snack3
  3.1.5.9

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。
. 表示一个子节点
['' (, '')] 表示一个或多个子节点
[ (, )] 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)
[?()] 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}]

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