2,JsonPath入门实战

1,json例子数据

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
}

2,最新maven坐标:

<dependency>
    <groupId>com.jayway.jsonpath</groupId>
    <artifactId>json-path</artifactId>
    <version>2.7.0</version>
</dependency>

3,Java代码

package com.lcj.jsonpath;  
  
import cn.hutool.core.io.resource.ResourceUtil;  
import cn.hutool.core.lang.Console;  
import com.jayway.jsonpath.Configuration;  
import com.jayway.jsonpath.JsonPath;  
import org.junit.Before;  
import org.junit.Test;  
  
/**  
 * <p>  
 * 使用jsonpath查询json字符串数据  
 * </p>  
 * * @author: liuchangjun  
 * @since: 2022/7/15 12:04  
 */public class JsonPathDemoTest {  
    /**  
     * 从资源文件中读取json数据  
     */  
    private Object document;  
  
    @Before  
    public void init() {  
        // 读取资源下面的json文件  
        String jsonData = ResourceUtil.readUtf8Str("jsonpath_test_data.json");  
        // Console.log("json data: {}",jsonData);  
        document = Configuration.defaultConfiguration().jsonProvider().parse(jsonData);  
    }  
  
    @Test
    public void test() {
        // 所有书的作者
        // $.store.book[*].author <=> $['store']['book'][*]['author']
        // List<String> allBookAuthors = JsonPath.read(document,"$.store.book[*].author");
        // Console.log(allBookAuthors);

        // 所有的作者
        // $..author <=> $..['author']
        // List<String> allAuthors = JsonPath.read(document,"$..author");
        // Console.log(allAuthors);

        // store下所有的子节点,包含 book 和 bicycle
        // $.store.* <=> $['store'][*]
        // List<Object> list = JsonPath.read(document,"$.store.*");
        // Console.log(list);

        // 所有的价格
        // $.store..price
        // List<Double> allPrice = JsonPath.read(document,"$.store..price");
        // Console.log(allPrice);

        // 第三本书 数组索引从0开始
        // $..book[2] <=>  $..['book'][2]
        // List<Object> thirdBook = JsonPath.read(document, "$..book[2]");
        // Console.log(thirdBook);

        // 倒数第二本书 数组逆序索引从-1开始
        // $..book[-2] <=> $..['book'][-2]
        // List<Object> lastSecondBook = JsonPath.read(document, "$..book[-2]");
        // Console.log(lastSecondBook);

        // 前2本书
        // $..book[0,1] <=> $..['book'][0,1]
        // List<Object> twoBooks = JsonPath.read(document, "$..book[0,1]");
        // Console.log(twoBooks);

        // 从索引0开始到索引2(不包含)
        // $..book[:2]
        // List<Object> list = JsonPath.read(document, "$..book[:2]");
        // Console.log(list);

        // $..book[1:2]
        // List<Object> list = JsonPath.read(document, "$..book[1:2]");
        // Console.log(list);

        // 最后2本书
        // $..book[-2:]
        // List<Object> list = JsonPath.read(document, "$..book[-2:]");
        // Console.log(list);

        // $..book[2:]
        // List<Object> list = JsonPath.read(document, "$..book[2:]");
        // Console.log(list);

        // 包含isbn的book
        // $..book[?(@.isbn)]
        // List<Object> list = JsonPath.read(document, "$..book[?(@.isbn)]");
        // Console.log(list);

        // 书的价格小于10
        // $.store.book[?(@.price < 10)]
        // List<Object> list = JsonPath.read(document, "$..book[?(@.price < 10)]");
        // Console.log(list);

        // 书的价格小于 $['expensive']
        // $..book[?(@.price <= $['expensive'])] <=> $..book[?(@.price <= $.expensive)]
        // List<Object> list = JsonPath.read(document, "$..book[?(@.price <= $.expensive)]");
        // Console.log(list);

        // 所有book的作者匹配正则 /.*REES/i 忽略大小写
        // $..book[?(@.author =~ /.*REES/i)]
        // List<Object> list = JsonPath.read(document, "$..book[?(@.author =~ /.*REES/i)]");
        // Console.log(list);

        // 将json字符串解析为一个个单值
        // $..*
        // List<Object> list = JsonPath.read(document, "$..*");
        // Console.log(list);

        // book的数量
        // $..book.length()
        int len = JsonPath.read(document, "$..book.length()");
        // 4
        Console.log(len);
    }
}

注意: 以上代码打开注释即可执行