How to handle a JSON format string?

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Let’s say I receive the following content that is stored in a String:

{
    "client_id": 1580,
    "videos": 4,
    "remote_urls": [{
            "url": "rtsp://aniceurl.com"
        },
        {
            "url": "rtsp://aniceurl.com"
        },
        {
            "url": "rtsp://aniceurl.com"
        },
        {
            "url": "rtsp://aniceurl.com"
        }
    ],
    "action": "start"
}

I recognize JSON and everything, but he’s saved in a String, not a Jsonobject. I would like to know how I can extract the information from it and store it in variables/arrays, so I can work with this data.

[]'s!

java json string

1 answer

4


you can use the Gson from google, it’s super simple, just create a class that has exactly the same attributes of json and parse, look at the example I did with your json, just using the method fromJson(meuJson, MinhaClasse.class):

Clientedto

import java.util.List;

public class ClienteDTO {
    private Integer client_id;
    private Integer videos;
    private List<RemoteUrlDTO> remote_urls;
    private String action;

    public Integer getClient_id() {
        return client_id;
    }
    public void setCliente_id(Integer cliente_id) {
        this.client_id = cliente_id;
    }
    public Integer getVideos() {
        return videos;
    }
    public void setVideos(Integer videos) {
        this.videos = videos;
    }
    public List<RemoteUrlDTO> getRemote_urls() {
        return remote_urls;
    }
    public void setRemote_urls(List<RemoteUrlDTO> remote_urls) {
        this.remote_urls = remote_urls;
    }
    public String getAction() {
        return action;
    }
    public void setAction(String action) {
        this.action = action;
    }
    @Override
    public String toString() {
        return "ClienteDTO [cliente_id=" + client_id + ", videos=" + videos + ", remote_urls=" + remote_urls
                + ", action=" + action + "]";
    }
}

Remoteurldto

public class RemoteUrlDTO {
    private String url;

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    @Override
    public String toString() {
        return "RemoteUrlDTO [url=" + url + "]";
    }
}

Class to test and demonstrate GSON:

import com.google.gson.Gson;

public class Main {
    public static void main(String[] args) {
        Gson g = new Gson();
        String json = "{\n" +
                "    \"client_id\": 1580,\n" +
                "    \"videos\": 4,\n" +
                "    \"remote_urls\": [{\n" +
                "            \"url\": \"rtsp://aniceurl.com\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"url\": \"rtsp://aniceurl.com\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"url\": \"rtsp://aniceurl.com\"\n" +
                "        },\n" +
                "        {\n" +
                "            \"url\": \"rtsp://aniceurl.com\"\n" +
                "        }\n" +
                "    ],\n" +
                "    \"action\": \"start\"\n" +
                "}\n" +
                "\n";


        ClienteDTO clienteDTO = g.fromJson(json, ClienteDTO.class);

        System.out.println(clienteDTO);
    }
}

Result after execution of the test

ClienteDTO [cliente_id=1580, videos=4, remote_urls=[RemoteUrlDTO [url=rtsp://aniceurl.com], RemoteUrlDTO [url=rtsp://aniceurl.com], RemoteUrlDTO [url=rtsp://aniceurl.com], RemoteUrlDTO [url=rtsp://aniceurl.com]], action=start]

  • I think I understand how to use it! Could you explain to me just the "fromJson(meuJson, Minhaclasse.class)" part? How does it work? What class should I put as a parameter? Thank you!

  • 1

    Simple, in the fromJson method it expects two parameters, the first is a string that contains your json and the other is the class that has the same attributes as the.

  • 1

    vc does not need to touch this remoteurldto, because moving will break the parser of json to object, what you can do is access the url object like this : for (int i = 0; i < numVideo; i++) { mediaPlayer[i]. playMedia(clientDTO.getRemote_urls(). get(i). geturl()); }

  • 1

    I am assuming that you received a json and parsed it for the client class, so you should use that same instance to do this procedure.

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