最近团队开发了一个平台，功能界面类似postman，用例都还是单接口的用例，就是可以绑定一个用户的登录状态和一些常量。验证功能主要分为两类：1、系统验证（包括请求异常、HTTP状态码、通用响应结构验证）；2、功能验证（包括业务code、文本内容等）。都是通过字符串解析和正则匹配来完成的。
接下来的二期有一个目标就是丰富验证功能和多用例串联起来，这里了解到了一个jsonpath的工具，经过简单尝试，效果非常理想。因为每一个用例都对应这一个请求，执行完都会返回一个JSonobject的对象（这里是框架封装好的）。如果使用JSonpath的标记语言能够完成json信息的提取，那么就可以完美解决这个需求。
下面分享一下官方的API的实践。
引入jar包
compile group: 'com.jayway.jsonpath', name: 'json-path', version: '2.4.0'
json数据
首先看官方给的json数据的Demo（我做了一点点修改）：
JSONObject json = JSON.parseObject("{" +
" "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," +
" "ss": [32,32,4,23]" +
"}");
jsonpath的两种写法
JsonPath表达式始终以与XPath表达式与XML文档结合使用的方式解析JSON结构数据。JsonPath中的根对象或者数组用$表示。
JsonPath表达式可以使用点符号
$.store.book[0].title
或括号符号
$['store']['book'][0]['title']
API
基本的是一个read()方法：
/**
* Creates a new JsonPath and applies it to the provided Json object
*
* @param json a json object
* @param jsonPath the json path
* @param filters filters to be applied to the filter place holders [?] in the path
* @param <T> expected return type
* @return list of objects matched by the given path
*/
@SuppressWarnings({"unchecked"})
public static <T> T read(Object json, String jsonPath, Predicate... filters) {
return parse(json).read(jsonPath, filters);
}
- 对于测试来讲，只需要两个参数即可，足够满足所有使用场景了，而且后面的参数对象对于
fastjson兼容性不咋好，部分高级语法不支持这个。
获取所有图书的作者列表
jsonpath：$.store.book[*].author
代码：
Object read = JsonPath.read(json, "$.store.book[*].author");
output(read);
这里可以完全自定义返回对象类型，jsonpath会自动帮用户完成对象转换，跟下面的这个写法是完全等效的。
List read = JsonPath.read(json, "$.store.book[*].author");
output(read);
输出：
INFO-> 当前用户：fv，IP：10.60.192.21，工作目录：/Users/fv/Documents/workspace/fun/,系统编码格式:UTF-8,系统Mac OS X版本:10.15.6
INFO-> ["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]
可以看到得到了无论使用object或者list得到的结果都是一样的，但是如果使用的不当的对象类型，就会报下面的错误：
Exception in thread "main" java.lang.ClassCastException: net.minidev.json.JSONArray cannot be cast to java.lang.String
at com.fun.ztest.groovy.JsonPathTest.main(JsonPathTest.java:50)
获取所有作者
JSonpath：$..author
$.store..price
代码省略，输出：
INFO-> 当前用户：fv，IP：10.60.192.21，工作目录：/Users/fv/Documents/workspace/fun/,系统编码格式:UTF-8,系统Mac OS X版本:10.15.6
INFO-> ["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]
INFO-> 当前用户：fv，IP：10.60.192.21，工作目录：/Users/fv/Documents/workspace/fun/,系统编码格式:UTF-8,系统Mac OS X版本:10.15.6
INFO-> [19.95,8.95,12.99,8.99,22.99]
可以看到可以不指定具体的key也可以获取固定层级的某个key的value。
获取节点下所有信息
JSonpath：$.store.*JSonpath：$.ss.*
代码省略，输出：
INFO-> 当前用户：fv，IP：10.60.192.21，工作目录：/Users/fv/Documents/workspace/fun/,系统编码格式:UTF-8,系统Mac OS X版本:10.15.6
INFO-> [{"color":"red","price":19.95},[{"author":"Nigel Rees","price":8.95,"category":"reference","title":"Sayings of the Century"},{"author":"Evelyn Waugh","price":12.99,"category":"fiction","title":"Sword of Honour"},{"author":"Herman Melville","price":8.99,"isbn":"0-553-21311-3","category":"fiction","title":"Moby Dick"},{"author":"J. R. R. Tolkien","price":22.99,"isbn":"0-395-19395-8","category":"fiction","title":"The Lord of the Rings"}]]
INFO-> 当前用户：fv，IP：10.60.192.21，工作目录：/Users/fv/Documents/workspace/fun/,系统编码格式:UTF-8,系统Mac OS X版本:10.15.6
INFO-> [32,32,4,23]
下期讲讲如果处理json数组，欢迎继续关注！
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