How to post&get Data through java.net.HttpURLConnection[Android/Java]

This article describes “How to post Data / get Data through java.net.HttpURLConnection to access the webservice”.

Set allow domain to res/xml/network_security_config.xml:


<network-security-config>
    <domain-config usesCleartextTraffic="false">
        <domain includeSubdomains="true">example.comdomain>
    domain-config>
network-security-config>

Sample code for getting or posting data is as follows:

public class PostCall {
    private static final String USER_AGENT = "Mozilla/5.0 (Linux; ; ) AppleWebKit/ (KHTML, like Gecko) Chrome/ Mobile Safari/";

    public void doSomething() {
        String getResult = getUrl(new URL("http://example.com/get_end_point"));

        MyRequest request = new MyRequest(something);
        String postResult = postJson(new URL(SCRAPED_HTML_URL_END_POINT), new Gson().toJson(request));
        String postResult = postJson(new URL("http://example.com/get_end_point"), );
    }
    
    private String getUrl(URL url) {
        HttpURLConnection c = null;

        try{
            c = (HttpURLConnection)url.openConnection();
            c.setRequestProperty("Content-length", "0");
            c.setRequestProperty("User-Agent", USER_AGENT);
            c.setRequestMethod("GET");
            c.setRequestProperty("Content-Type", "application/json");
            c.setUseCaches(false);
            c.setAllowUserInteraction(false);
            c.setConnectTimeout(3000);
            c.setReadTimeout(3000);

            c.connect();
            int status = c.getResponseCode();

            switch (status) {
                case 200:
                case 201:
                    BufferedReader br = new BufferedReader(new InputStreamReader(c.getInputStream()));
                    StringBuilder sb = new StringBuilder();
                    String line;
                    while ((line = br.readLine()) != null) {
                        sb.append(line + "\n");
                    }
                    br.close();
                    return sb.toString();
            }
        } catch (MalformedURLException ex) {
            Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
        } finally {
            if (c != null) {
                try {
                    c.disconnect();
                } catch (Exception ex) {
                    Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
                }
            }
        }

        return "";
    }

    private String postJson(URL url, String json) {
        HttpURLConnection c = null;

        try{
            c = (HttpURLConnection)url.openConnection();
            c.setRequestProperty("Content-length", String.valueOf(json.getBytes().length));
            c.setRequestProperty("User-Agent", USER_AGENT);
            c.setRequestMethod("POST");
            c.setRequestProperty("Content-Type", "application/json");
            c.setDoInput(true);
            c.setDoOutput(true);
            c.setUseCaches(false);
            c.setAllowUserInteraction(false);
            c.setConnectTimeout(3000);
            c.setReadTimeout(3000);

            OutputStream os = c.getOutputStream();
            os.write(json.getBytes());
            os.flush();
            os.close();

            c.connect();
            int status = c.getResponseCode();

            switch (status) {
                case 200:
                case 201:
                    BufferedReader br = new BufferedReader(new InputStreamReader(c.getInputStream()));
                    StringBuilder sb = new StringBuilder();
                    String line;
                    while ((line = br.readLine()) != null) {
                        sb.append(line+"\n");
                    }
                    br.close();
                    return sb.toString();
            }
        } catch (MalformedURLException ex) {
            Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
        } catch (IOException ex) {
            Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
        } finally {
            if (c != null) {
                try {
                    c.disconnect();
                } catch (Exception ex) {
                    Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
                }
            }
        }

        return "";
    }
}

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mockable.io can create your API mock.

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