Apache HttpClient Examples
By:Roy.LiuLast updated:2019-08-18
This article shows you how to use Apache HttpClient to send HTTP GET/POST request.
1. Send HTTP GET Request
HttpClient to send a HTTP GET request to get the Google’s search result.
String url = "http://www.google.com/search?q=httpClient"; HttpClient client = HttpClientBuilder.create().build(); HttpGet request = new HttpGet(url); // add request header request.addHeader("User-Agent", USER_AGENT); HttpResponse response = client.execute(request); System.out.println("Response Code : " + response.getStatusLine().getStatusCode()); BufferedReader rd = new BufferedReader( new InputStreamReader(response.getEntity().getContent())); StringBuffer result = new StringBuffer(); String line = ""; while ((line = rd.readLine()) != null) { result.append(line);
2. Send HTTP POST Request
HttpClient to send an HTTP POST request to Apple.com search form.
String url = "https://selfsolve.apple.com/wcResults.do"; HttpClient client = HttpClientBuilder.create().build(); HttpPost post = new HttpPost(url); // add header post.setHeader("User-Agent", USER_AGENT); List<NameValuePair> urlParameters = new ArrayList<NameValuePair>(); urlParameters.add(new BasicNameValuePair("sn", "C02G8416DRJM")); urlParameters.add(new BasicNameValuePair("cn", "")); urlParameters.add(new BasicNameValuePair("locale", "")); urlParameters.add(new BasicNameValuePair("caller", "")); urlParameters.add(new BasicNameValuePair("num", "12345")); post.setEntity(new UrlEncodedFormEntity(urlParameters)); HttpResponse response = client.execute(post); System.out.println("Response Code : " + response.getStatusLine().getStatusCode()); BufferedReader rd = new BufferedReader( new InputStreamReader(response.getEntity().getContent())); StringBuffer result = new StringBuffer(); String line = ""; while ((line = rd.readLine()) != null) { result.append(line);
3. Apache HttpClient – Automate login Google
A full example to automate login to Gmail.
Send a GET request to get login form.
Uses jsoup html parser to grab form inputs.
Constructs parameters and make a POST request for authentication.
Send another GET request to Gmail.
HttpCilentExample.java
package com.mkyong; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.net.CookieHandler; import java.net.CookieManager; import java.util.ArrayList; import java.util.List; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.HttpClientBuilder; import org.apache.http.message.BasicNameValuePair; import org.jsoup.Jsoup; import org.jsoup.nodes.Document; import org.jsoup.nodes.Element; import org.jsoup.select.Elements; public class HttpCilentExample { private String cookies; private HttpClient client = HttpClientBuilder.create().build(); private final String USER_AGENT = "Mozilla/5.0"; public static void main(String[] args) throws Exception { String url = "https://accounts.google.com/ServiceLoginAuth"; String gmail = "https://mail.google.com/mail/"; // make sure cookies is turn on CookieHandler.setDefault(new CookieManager()); HttpCilentExample http = new HttpCilentExample(); String page = http.GetPageContent(url); List<NameValuePair> postParams = http.getFormParams(page, "username","password"); http.sendPost(url, postParams); String result = http.GetPageContent(gmail); System.out.println(result); System.out.println("Done"); private void sendPost(String url, List<NameValuePair> postParams) throws Exception { HttpPost post = new HttpPost(url); // add header post.setHeader("Host", "accounts.google.com"); post.setHeader("User-Agent", USER_AGENT); post.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"); post.setHeader("Accept-Language", "en-US,en;q=0.5"); post.setHeader("Cookie", getCookies()); post.setHeader("Connection", "keep-alive"); post.setHeader("Referer", "https://accounts.google.com/ServiceLoginAuth"); post.setHeader("Content-Type", "application/x-www-form-urlencoded"); post.setEntity(new UrlEncodedFormEntity(postParams)); HttpResponse response = client.execute(post); int responseCode = response.getStatusLine().getStatusCode(); System.out.println("\nSending 'POST' request to URL : " + url); System.out.println("Post parameters : " + postParams); System.out.println("Response Code : " + responseCode); BufferedReader rd = new BufferedReader( new InputStreamReader(response.getEntity().getContent())); StringBuffer result = new StringBuffer(); String line = ""; while ((line = rd.readLine()) != null) { result.append(line); // System.out.println(result.toString()); private String GetPageContent(String url) throws Exception { HttpGet request = new HttpGet(url); request.setHeader("User-Agent", USER_AGENT); request.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"); request.setHeader("Accept-Language", "en-US,en;q=0.5"); HttpResponse response = client.execute(request); int responseCode = response.getStatusLine().getStatusCode(); System.out.println("\nSending 'GET' request to URL : " + url); System.out.println("Response Code : " + responseCode); BufferedReader rd = new BufferedReader( new InputStreamReader(response.getEntity().getContent())); StringBuffer result = new StringBuffer(); String line = ""; while ((line = rd.readLine()) != null) { result.append(line); // set cookies setCookies(response.getFirstHeader("Set-Cookie") == null ? "" : response.getFirstHeader("Set-Cookie").toString()); return result.toString(); public List<NameValuePair> getFormParams( String html, String username, String password) throws UnsupportedEncodingException { System.out.println("Extracting form's data..."); Document doc = Jsoup.parse(html); // Google form id Element loginform = doc.getElementById("gaia_loginform"); Elements inputElements = loginform.getElementsByTag("input"); List<NameValuePair> paramList = new ArrayList<NameValuePair>(); for (Element inputElement : inputElements) { String key = inputElement.attr("name"); String value = inputElement.attr("value"); if (key.equals("Email")) value = username; else if (key.equals("Passwd")) value = password; paramList.add(new BasicNameValuePair(key, value)); return paramList; public String getCookies() { return cookies; public void setCookies(String cookies) { this.cookies = cookies;
Note
You may also interest at this equivalent example – automate login Gmail with Java HttpsURLConnection
References
From:一号门
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