之前分享了jsonpath的部分API使用，基本已经把基础的内容讲完了，今天分享一下JsonPath API中的函数的使用方法，其实之前讲到的一些json数组的过滤中已经用到了一些函数，大概是因为功能不一样吧，这里将的函数都是处理json数组的，而不是过滤数组的条件。
在原来的数据基础上增加了部分字段和部分节点。
JSONObject json = JSON.parseObject("{" +
" \"store\": {" +
" \"book\": [" +
" {" +
" \"category\": \"reference\"," +
" \"author\": \"Nigel Rees\"," +
" \"title\": \"Sayings of the Century\"," +
" \"page\": \"D\"," +
" \"pages\": [\"S\",\"X\",\"G\"]," +
" \"price\": 8.95" +
" }," +
" {" +
" \"category\": \"fiction\"," +
" \"author\": \"Evelyn Waugh\"," +
" \"title\": \"Sword of Honour\"," +
" \"page\": \"A\"," +
" \"pages\": [\"A\",\"B\"]," +
" \"price\": 12.99" +
" }," +
" {" +
" \"category\": \"fiction\"," +
" \"author\": \"Herman Melville\"," +
" \"title\": \"Moby Dick\"," +
" \"isbn\": \"0-553-21311-3\"," +
" \"page\": \"B\"," +
" \"pages\": [\"E\",\"F\"]," +
" \"price\": 8.99" +
" }," +
" {" +
" \"category\": \"fiction\"," +
" \"author\": \"J. R. R. Tolkien\"," +
" \"title\": \"The Lord of the Rings\"," +
" \"isbn\": \"0-395-19395-8\"," +
" \"page\": \"C\"," +
" \"pages\": [\"C\",\"D\"]," +
" \"price\": 22.99" +
" }" +
" ]," +
" \"bicycle\": {" +
" \"color\": \"red\"," +
" \"price\": 19.95" +
" }" +
" }," +
" \"expensive\": 10," +
" \"ss\": [32,32,4,23]" +
"}");
jsonpath：$.ss.min()
代码：
Object read = JsonPath.read(json, "$.ss.min()");
output(read);
等效写法继续省略……
控制台输出：
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-> 4.0
Process finished with exit code 0
double的数值，测试中用的int整型，但是结果返回的是4.0。jsonpath：$.ss.max()
代码：
Object read = JsonPath.read(json, "$.ss.max()");
output(read);
等效写法继续省略……
控制台输出：
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-> 32.0
Process finished with exit code 0
max函数返回的也是double浮点型数据。jsonpath：$.ss.avg()
代码：
Object read = JsonPath.read(json, "$.ss.avg()");
output(read);
等效写法继续省略……
控制台输出：
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-> 22.75
Process finished with exit code 0
max函数返回的也是double浮点型数据。jsonpath：$.ss.stddev()
代码：
Object read = JsonPath.read(json, "$.ss.stddev()");
output(read);
等效写法继续省略……
控制台输出：
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-> 11.431863365173676
Process finished with exit code 0
stddev函数返回的也是double浮点型数据。json数组适用。jsonpath：$.ss.length()
jsonpath：$.store.book.length()
代码：
Object read = JsonPath.read(json, "$.ss.length()");
output(read);
Object read = JsonPath.read(json, "$.store.book.length()");
output(read);
等效写法继续省略……
控制台输出：
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-> 4
Process finished with exit code 0
jsonpath：$.ss.sum()
代码：
Object read = JsonPath.read(json, "$.ss.sum()");
output(read);
等效写法继续省略……
控制台输出：
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-> 91.0
Process finished with exit code 0
sun函数返回的也是double浮点型数据。自此，JsonPath API系列已经更完了，我在积极准备JsonPath util的内容，使用Groovy的Groovy 重载操作符（终极版）功能，敬请期待。