SpringBoot+JaywayJsonPath实现Json数据的DSL(按照指定节点表达式解析json获取指定数据)

场景

若依前后端分离版手把手教你本地搭建环境并运行项目：

若依前后端分离版手把手教你本地搭建环境并运行项目_前后端分离项目本地运行-CSDN博客

在上面搭建SpringBoot项目的基础上，并且在项目中引入fastjson、hutool等所需依赖后。

Jayway JsonPath：

GitHub - json-path/JsonPath: Java JsonPath implementation

A Java DSL for reading JSON documents

需要对接第三方接口，接口返回的json数据需要解析获取数据。

可以通过配置每个返回字段的对应json数据的表达式，使其在代码中根据配置的表达式动态获取。

注：

博客：
霸道流氓气质_C#,架构之路,SpringBoot-CSDN博客

实现

1、添加项目依赖

        <dependency><groupId>com.jayway.jsonpath</groupId><artifactId>json-path</artifactId><version>2.8.0</version></dependency>

2、JsonPath表达式引用JSON结构的方式与XPath表达式与XML文档结合使用的方式相同。

采用接口模拟工具模拟官方提供的示例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
}

3、快速开始

解析上面json数据中所有book节点的author字段信息

List<String> authors = JsonPath.read(body, "$.store.book[*].author");

获取第一本书的title字段

String title = JsonPath.read(body, "$['store']['book'][0]['title']");

也可以这样写

String title2 = JsonPath.read(body, "$.store.book[0].title");

获取所有book的数量

Integer number = JsonPath.read(body, "$..book.length()");

获取所有价格大于10的book

List<Map<String, Object>> expensiveBooks= JsonPath.read(body, "$.store.book[?(@.price > 10)]");

4、Json Path的语法较多，各种符号、函数、过滤等可参考官方文档。

下面记录一个读取json数据中指定结构的list数据。

首先需要读取所有book的数量，然后遍历循环，再通过配置的json数据的映射关系

获取配置的映射关系的表达式，进而解析获取对应字段的数据。

            int dataSize = JsonPath.read(body, "$..book.length()");JSONObject mapping = JSON.parseObject("{\"title\":\"$.store.book[%d].title\",\"author\":\"$.store.book[%d].author\"}");for (int i = 0; i < dataSize; i++) {String titleName = mapping.containsKey("title") ? JsonPath.read(body, String.format(mapping.getString("title"), i)).toString() : null;System.out.println(titleName);String author = mapping.containsKey("author") ? JsonPath.read(body, String.format(mapping.getString("author"), i)).toString() : null;System.out.println(author);}

其中JSON.parseObject是引用的fastjson。

单元测试结果

5、完整单元测试示例代码

​
import cn.hutool.http.HttpRequest;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.jayway.jsonpath.JsonPath;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.List;
import java.util.Map;@RunWith(SpringRunner.class)
@SpringBootTest(classes = RuoYiApplication.class,webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class JsonPathTest {@Testpublic void getData() {String body = "";try {//模拟获取接口数据body = HttpRequest.get("http://127.0.0.1:4523/m1/2858210-0-default/testJsonPath").timeout(20000).execute().body();//获取book的所有autherList<String> authors = JsonPath.read(body, "$.store.book[*].author");System.out.println(authors);//第一本book的titleString title = JsonPath.read(body, "$['store']['book'][0]['title']");String title2 = JsonPath.read(body, "$.store.book[0].title");System.out.println(title);System.out.println(title2);//所有book 的数量Integer number = JsonPath.read(body, "$..book.length()");System.out.println(number);//获取所有价格大于10的bookList<Map<String, Object>> expensiveBooks= JsonPath.read(body, "$.store.book[?(@.price > 10)]");System.out.println(expensiveBooks);//根据配置的json数据的映射关系，获取指定表达式下的数据int dataSize = JsonPath.read(body, "$..book.length()");JSONObject mapping = JSON.parseObject("{\"title\":\"$.store.book[%d].title\",\"author\":\"$.store.book[%d].author\"}");for (int i = 0; i < dataSize; i++) {String titleName = mapping.containsKey("title") ? JsonPath.read(body, String.format(mapping.getString("title"), i)).toString() : null;System.out.println(titleName);String author = mapping.containsKey("author") ? JsonPath.read(body, String.format(mapping.getString("author"), i)).toString() : null;System.out.println(author);}} catch (Exception e) {e.printStackTrace();}}
}​