How to search/find In JSON with java

问题

I have a below JSON string from the below i want to find/search criteria in JSON String.

1). To find the Number of keys present. 2). To get the values of given key(if we have array)

{
"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
}

I am looking a solution like Groovy GPath Syntax

• store.book - size of this array.
• store.book[*].category - how may times the key present in the array.
• store.bicycle - if it found it has to return true value

回答1:

You can also use the JsonPath project provided by REST Assured. This JsonPath project uses Groovy GPath expressions. In Maven you can depend on it like this:

<dependency>
    <groupId>com.jayway.restassured</groupId>
    <artifactId>json-path</artifactId>
    <version>2.4.0</version>
</dependency>

Examples:

To get a list of all book categories:

List<String> categories = JsonPath.from(json).get("store.book.category");

Get the first book category:

String category = JsonPath.from(json).get("store.book[0].category");

Get the last book category:

String category = JsonPath.from(json).get("store.book[-1].category");

Get all books with price between 5 and 15:

List<Map> books = JsonPath.from(json).get("store.book.findAll { book -> book.price >= 5 && book.price <= 15 }");

GPath is very powerful and you can make use of higher order functions and all Groovy data structures in your path expressions.

回答2:

I would try the following library

https://github.com/jayway/JsonPath

http://jsonpath.herokuapp.com/?path=%24.store.book[*]

gives you all books

回答3:

First of all you have to add dependency

<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20090211</version>
</dependency>

Then you can use this code:

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.XML;

public class Main {

    public static int PRETTY_PRINT_INDENT_FACTOR = 4;
    public static String TEST_XML_STRING =
        "<Result><ResultParameters><ResultParameter><Key>TransEndDate</Key><Value>20170731</Value></ResultParameter><ResultParameter><Key>Failed Reason</Key><Value>Operator 03058361178\03058365278 has no permission to perform the Check Balance service.</Value></ResultParameter><ResultParameter><Key>TransEndTime</Key><Value>123611</Value></ResultParameter></ResultParameters><ResultCode>2000</ResultCode><ResultType>0</ResultType><OriginatorConversationID>S_X20130129210125</OriginatorConversationID><ResultDesc>Initiator authentication error.</ResultDesc><TransactionID>000749213589</TransactionID><ConversationID>AG_20170731_00004c28e51f1f822e9e</ConversationID></Result>";

    public static void main(String[] args) {
        try {
            JSONObject xmlJSONObj = XML.toJSONObject(TEST_XML_STRING);
            String jsonPrettyPrintString = xmlJSONObj.toString(PRETTY_PRINT_INDENT_FACTOR);
            System.out.println(jsonPrettyPrintString);


            System.out.println("Element="+xmlJSONObj.getJSONObject("Result").getInt("ResultCode"));

        } catch (JSONException je) {
            System.out.println(je.toString());
        }
    }
}

// in it i am searching an element which is present in a json object 

来源：https://stackoverflow.com/questions/28982412/how-to-search-find-in-json-with-java