在 Jayway JsonPath 中，concat() 函数用于连接两个或多个字符串。concat() 函数可以接受两个或多个参数，并将它们连接成一个字符串。这些参数可以是字面量字符串，也可以是 JSON 文档中的表达式。
注意：标准的 JSONPath 规范中并没有定义 concat() 函数，这是 Jayway JSONPath 实现特有的一个功能。
Java 示例：
package com.hxstrive.json_path.function;
import com.jayway.jsonpath.JsonPath;
/**
* concat() 函数
* @author hxstrive.com
*/
public class FunctionDemo08 {
public static void main(String[] args) {
String json = "{" +
" \"store\": {" +
" \"book\": [" +
" {" +
" \"category\": \"reference\"," +
" \"author\": \"Nigel Rees\"," +
" \"title\": \"Sayings of the Century\"," +
" \"price\": 8.95" +
" }," +
" {" +
" \"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" +
"}";
Object obj = JsonPath.read(json, "concat(\"color=\",$..bicycle.color, \", price=\", $..bicycle.price)");
System.out.println(obj);
}
}运行示例，输出如下：
color=red price=19.95
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