Java HTTP Post postForm(String url, Map params)

Description

Post a form with parameters

License

Open Source License

Parameter

Parameter	Description
url	Url as string
params	map with parameters/values

Exception

Parameter	Description
IOException	an exception

Return

response Response as string

Declaration

static public String postForm(String url, Map<String, String> params) throws IOException 

Method Source Code

//package com.java2s;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Map;

public class Main {
    /**/*from w  w  w .  java  2  s.c  om*/
     * Post a form with parameters
     *
     * @param url    Url as string
     * @param params map with parameters/values
     * @return response   Response as string
     * @throws IOException
     */
    static public String postForm(String url, Map<String, String> params) throws IOException {
        return postForm(url, params, null);
    }

    /**
     * Post a form with parameters
     *
     * @param url     Url as string
     * @param params  Map with parameters/values
     * @param headers Optional map with headers
     * @return response   Response as string
     * @throws IOException
     */
    static public String postForm(String url, Map<String, String> params, Map<String, String> headers)
            throws IOException {
        // set content type
        if (headers == null) {
            headers = new HashMap<String, String>();
        }
        headers.put("Content-Type", "application/x-www-form-urlencoded");

        // parse parameters
        String body = "";
        if (params != null) {
            boolean first = true;
            for (String param : params.keySet()) {
                if (first) {
                    first = false;
                } else {
                    body += "&";
                }
                String value = params.get(param);
                body += URLEncoder.encode(param, "UTF-8") + "=";
                body += URLEncoder.encode(value, "UTF-8");
            }
        }

        return post(url, body, headers);
    }

    /**
     * Send a put request
     *
     * @param url     Url as string
     * @param body    Request body as string
     * @param headers Optional map with headers
     * @return response   Response as string
     * @throws IOException
     */
    static public String put(String url, String body, Map<String, String> headers) throws IOException {
        return fetch("PUT", url, body, headers);
    }

    /**
     * Send a put request
     *
     * @param url Url as string
     * @return response   Response as string
     * @throws IOException
     */
    static public String put(String url, String body) throws IOException {
        return put(url, body, null);
    }

    /**
     * Send a get request
     *
     * @param url
     * @return response
     * @throws IOException
     */
    static public String get(String url) throws IOException {
        return get(url, null);
    }

    /**
     * Send a get request
     *
     * @param url     Url as string
     * @param headers Optional map with headers
     * @return response   Response as string
     * @throws IOException
     */
    static public String get(String url, Map<String, String> headers) throws IOException {
        return fetch("GET", url, null, headers);
    }

    /**
     * Send a post request
     *
     * @param url     Url as string
     * @param body    Request body as string
     * @param headers Optional map with headers
     * @return response   Response as string
     * @throws IOException
     */
    static public String post(String url, String body, Map<String, String> headers) throws IOException {
        return fetch("POST", url, body, headers);
    }

    /**
     * Send a post request
     *
     * @param url  Url as string
     * @param body Request body as string
     * @return response   Response as string
     * @throws IOException
     */
    static public String post(String url, String body) throws IOException {
        return post(url, body, null);
    }

    /**
     * Send a request
     *
     * @param method  HTTP method, for example "GET" or "POST"
     * @param url     Url as string
     * @param body    Request body as string
     * @param headers Optional map with headers
     * @return response   Response as string
     * @throws IOException
     */
    static public String fetch(String method, String url, String body, Map<String, String> headers)
            throws IOException {
        // connection
        URL u = new URL(url);
        HttpURLConnection conn = (HttpURLConnection) u.openConnection();
        conn.setConnectTimeout(10000);
        conn.setReadTimeout(10000);

        // method
        if (method != null) {
            conn.setRequestMethod(method);
        }

        // headers
        if (headers != null) {
            for (String key : headers.keySet()) {
                conn.addRequestProperty(key, headers.get(key));
            }
        }

        // body
        if (body != null) {
            conn.setDoOutput(true);
            OutputStream os = conn.getOutputStream();
            os.write(body.getBytes());
            os.flush();
            os.close();
        }

        // response
        InputStream is = conn.getInputStream();
        String response = streamToString(is);
        is.close();

        // handle redirects
        if (conn.getResponseCode() == 301) {
            String location = conn.getHeaderField("Location");
            return fetch(method, location, body, headers);
        }

        return response;
    }

    /**
     * Read an input stream into a string
     *
     * @param in
     * @return
     * @throws IOException
     */
    static public String streamToString(InputStream in) throws IOException {
        StringBuffer out = new StringBuffer();
        byte[] b = new byte[4096];
        for (int n; (n = in.read(b)) != -1;) {
            out.append(new String(b, 0, n));
        }
        return out.toString();
    }
}

Related

1. post(URL url, Map values)
2. post(URL url, String content)
3. post(URL url, String contentType, byte[] data)
4. postCall(JsonObject json, String url)
5. postData(Reader data, URL endpoint, Writer output)
6. postHTTPQuery(String url, String urlParameters)
7. postJSON(JSONObject job, HttpURLConnection conn)
8. postRaw(URL url, String params)
9. postURL(final URL url, final String request)