在 JsonPath 中,[start:end] 操作符表示获取数组中的一个子集,注意,包含 start,不包含 end。
Java 示例:
package com.hxstrive.json_path.operators; import com.jayway.jsonpath.JsonPath; /** * [start:end] 符号 * @author hxstrive.com */ public class OperatorsDemo08 { 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\": \"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" + "}"; Object obj = JsonPath.read(json, "$.store.book[1:3]"); System.out.println(obj); obj = JsonPath.read(json, "$.store.book[-1:2]"); System.out.println(obj); obj = JsonPath.read(json, "$.store.book[1:-1]"); System.out.println(obj); } }
运行示例,输出如下:
[{"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},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99}] []
从上述示例可知,[start:end] 中的,如果 start 为负数,则将从数组末尾开始算,如果 end 为负数好像没有什么效果。