本文主要是介绍Apache HttpClient使用详解,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
转载地址:http://eksliang.iteye.com/blog/2191017
Http协议的重要性相信不用我多说了,HttpClient相比传统JDK自带的URLConnection,增加了易用性和灵活性(具体区别,日后我们再讨论),它不仅是客户端发送Http请求变得容易,而且也方便了开发人员测试接口(基于Http协议的),即提高了开发的效率,也方便提高代码的健壮性。因此熟练掌握HttpClient是很重要的必修内容,掌握HttpClient后,相信对于Http协议的了解会更加深入。
一、简介
HttpClient是Apache Jakarta Common下的子项目,用来提供高效的、最新的、功能丰富的支持HTTP协议的客户端编程工具包,并且它支持HTTP协议最新的版本和建议。HttpClient已经应用在很多的项目中,比如Apache Jakarta上很著名的另外两个开源项目Cactus和HTMLUnit都使用了HttpClient。
二、特性
1. 基于标准、纯净的java语言。实现了Http1.0和Http1.1
2. 以可扩展的面向对象的结构实现了Http全部的方法(GET, POST, PUT, DELETE, HEAD, OPTIONS, and TRACE)。
3. 支持HTTPS协议。
4. 通过Http代理建立透明的连接。
5. 利用CONNECT方法通过Http代理建立隧道的https连接。
6. Basic, Digest, NTLMv1, NTLMv2, NTLM2 Session, SNPNEGO/Kerberos认证方案。
7. 插件式的自定义认证方案。
8. 便携可靠的套接字工厂使它更容易的使用第三方解决方案。
9. 连接管理器支持多线程应用。支持设置最大连接数,同时支持设置每个主机的最大连接数,发现并关闭过期的连接。
10. 自动处理Set-Cookie中的Cookie。
11. 插件式的自定义Cookie策略。
12. Request的输出流可以避免流中内容直接缓冲到socket服务器。
13. Response的输入流可以有效的从socket服务器直接读取相应内容。
14. 在http1.0和http1.1中利用KeepAlive保持持久连接。
15. 直接获取服务器发送的response code和 headers。
16. 设置连接超时的能力。
17. 实验性的支持http1.1 response caching。
18. 源代码基于Apache License 可免费获取
三、使用方法
Mavn坐标
- <dependency>
- <groupId>org.apache.httpcomponents</groupId>
- <artifactId>httpclient</artifactId>
- <version>4.3.4</version>
- </dependency>
使用HttpClient发送请求、接收响应很简单,一般需要如下几步即可。
1. 创建HttpClient对象。
2. 创建请求方法的实例,并指定请求URL。如果需要发送GET请求,创建HttpGet对象;如果需要发送POST请求,创建HttpPost对象。
3. 如果需要发送请求参数,可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数;对于HttpPost对象而言,也可调用setEntity(HttpEntity entity)方法来设置请求参数。
4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求,该方法返回一个HttpResponse。
5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头;调用HttpResponse的getEntity()方法可获取HttpEntity对象,该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。
6. 释放连接。无论执行方法是否成功,都必须释放连接
四.post跟get请求示例
- package com.ickes;
- import java.util.ArrayList;
- import java.util.List;
- import org.apache.http.HttpEntity;
- import org.apache.http.NameValuePair;
- import org.apache.http.client.entity.UrlEncodedFormEntity;
- import org.apache.http.client.methods.CloseableHttpResponse;
- import org.apache.http.client.methods.HttpGet;
- import org.apache.http.client.methods.HttpPost;
- import org.apache.http.entity.StringEntity;
- import org.apache.http.impl.client.CloseableHttpClient;
- import org.apache.http.impl.client.HttpClients;
- import org.apache.http.message.BasicNameValuePair;
- import org.apache.http.protocol.HTTP;
- import org.apache.http.util.EntityUtils;
- public class HttpClientDemo {
- public static void main(String[] args) throws Exception {
- get();
- }
- /**
- * post方式提交json代码
- * @throws Exception
- */
- public static void postJson() throws Exception{
- //创建默认的httpClient实例.
- CloseableHttpClient httpclient = null;
- //接收响应结果
- CloseableHttpResponse response = null;
- try {
- //创建httppost
- httpclient = HttpClients.createDefault();
- String url ="http://192.168.16.36:8081/goSearch/gosuncn/deleteDocs.htm";
- HttpPost httpPost = new HttpPost(url);
- httpPost.addHeader(HTTP.CONTENT_TYPE,"application/x-www-form-urlencoded");
- //参数
- String json ="{'ids':['html1','html2']}";
- StringEntity se = new StringEntity(json);
- se.setContentEncoding("UTF-8");
- se.setContentType("application/json");//发送json需要设置contentType
- httpPost.setEntity(se);
- response = httpclient.execute(httpPost);
- //解析返结果
- HttpEntity entity = response.getEntity();
- if(entity != null){
- String resStr = EntityUtils.toString(entity, "UTF-8");
- System.out.println(resStr);
- }
- } catch (Exception e) {
- throw e;
- }finally{
- httpclient.close();
- response.close();
- }
- }
- /**
- * post方式提交表单(模拟用户登录请求)
- * @throws Exception
- */
- public static void postForm() throws Exception {
- // 创建默认的httpClient实例.
- CloseableHttpClient httpclient = null;
- //发送请求
- CloseableHttpResponse response = null;
- try {
- httpclient = HttpClients.createDefault();
- // 创建httppost
- String url= "http://localhost:8080/search/ajx/user.htm";
- HttpPost httppost = new HttpPost(url);
- // 创建参数队列
- List<NameValuePair> formparams = new ArrayList<NameValuePair>();
- formparams.add(new BasicNameValuePair("username", "admin"));
- formparams.add(new BasicNameValuePair("password", "123456"));
- //参数转码
- UrlEncodedFormEntity uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");
- httppost.setEntity(uefEntity);
- response = httpclient.execute(httppost);
- HttpEntity entity = response.getEntity();
- if (entity != null) {
- System.out.println(EntityUtils.toString(entity, "UTF-8"));
- }
- //释放连接
- } catch (Exception e) {
- throw e;
- }finally{
- httpclient.close();
- response.close();
- }
- }
- /**
- * 发送 get请求
- * @throws Exception
- */
- public static void get() throws Exception {
- CloseableHttpClient httpclient = null;
- CloseableHttpResponse response = null;
- try {
- httpclient = HttpClients.createDefault();
- // 创建httpget.
- HttpGet httpget = new HttpGet("http://www.baidu.com/");
- // 执行get请求.
- response = httpclient.execute(httpget);
- // 获取响应实体
- HttpEntity entity = response.getEntity();
- // 打印响应状态
- System.out.println(response.getStatusLine().getStatusCode());
- if (entity != null) {
- // 打印响应内容
- System.out.println("Response content: " + EntityUtils.toString(entity));
- }
- } catch (Exception e) {
- throw e;
- }finally{
- httpclient.close();
- response.close();
- }
- }
- }
五、SSL跟上传文件实例
- package com.test;
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.IOException;
- import java.io.UnsupportedEncodingException;
- import java.security.KeyManagementException;
- import java.security.KeyStore;
- import java.security.KeyStoreException;
- import java.security.NoSuchAlgorithmException;
- import java.security.cert.CertificateException;
- import java.util.ArrayList;
- import java.util.List;
- import javax.net.ssl.SSLContext;
- import org.apache.http.HttpEntity;
- import org.apache.http.NameValuePair;
- import org.apache.http.ParseException;
- import org.apache.http.client.ClientProtocolException;
- import org.apache.http.client.entity.UrlEncodedFormEntity;
- import org.apache.http.client.methods.CloseableHttpResponse;
- import org.apache.http.client.methods.HttpGet;
- import org.apache.http.client.methods.HttpPost;
- import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
- import org.apache.http.conn.ssl.SSLContexts;
- import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
- import org.apache.http.entity.ContentType;
- import org.apache.http.entity.mime.MultipartEntityBuilder;
- import org.apache.http.entity.mime.content.FileBody;
- import org.apache.http.entity.mime.content.StringBody;
- import org.apache.http.impl.client.CloseableHttpClient;
- import org.apache.http.impl.client.HttpClients;
- import org.apache.http.message.BasicNameValuePair;
- import org.apache.http.util.EntityUtils;
- import org.junit.Test;
- public class HttpClientTest {
- @Test
- public void jUnitTest() {
- ssl();
- }
- /**
- * HttpClient连接SSL
- */
- public void ssl() {
- CloseableHttpClient httpclient = null;
- try {
- KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
- FileInputStream instream = new FileInputStream(new File("d:\\tomcat.keystore"));
- try {
- // 加载keyStore d:\\tomcat.keystore
- trustStore.load(instream, "123456".toCharArray());
- } catch (CertificateException e) {
- e.printStackTrace();
- } finally {
- try {
- instream.close();
- } catch (Exception ignore) {
- }
- }
- // 相信自己的CA和所有自签名的证书
- SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore, new TrustSelfSignedStrategy()).build();
- // 只允许使用TLSv1协议
- SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[] { "TLSv1" }, null,
- SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
- httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();
- // 创建http请求(get方式)
- HttpGet httpget = new HttpGet("https://localhost:8443/myDemo/Ajax/serivceJ.action");
- System.out.println("executing request" + httpget.getRequestLine());
- CloseableHttpResponse response = httpclient.execute(httpget);
- try {
- HttpEntity entity = response.getEntity();
- System.out.println("----------------------------------------");
- System.out.println(response.getStatusLine());
- if (entity != null) {
- System.out.println("Response content length: " + entity.getContentLength());
- System.out.println(EntityUtils.toString(entity));
- EntityUtils.consume(entity);
- }
- } finally {
- response.close();
- }
- } catch (ParseException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- } catch (KeyManagementException e) {
- e.printStackTrace();
- } catch (NoSuchAlgorithmException e) {
- e.printStackTrace();
- } catch (KeyStoreException e) {
- e.printStackTrace();
- } finally {
- if (httpclient != null) {
- try {
- httpclient.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }
- }
- /**
- * 上传文件
- */
- public void upload() {
- CloseableHttpClient httpclient = HttpClients.createDefault();
- try {
- HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceFile.action");
- FileBody bin = new FileBody(new File("F:\\image\\sendpix0.jpg"));
- StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN);
- HttpEntity reqEntity = MultipartEntityBuilder.create().addPart("bin", bin).addPart("comment", comment).build();
- httppost.setEntity(reqEntity);
- System.out.println("executing request " + httppost.getRequestLine());
- CloseableHttpResponse response = httpclient.execute(httppost);
- try {
- System.out.println("----------------------------------------");
- System.out.println(response.getStatusLine());
- HttpEntity resEntity = response.getEntity();
- if (resEntity != null) {
- System.out.println("Response content length: " + resEntity.getContentLength());
- }
- EntityUtils.consume(resEntity);
- } finally {
- response.close();
- }
- } catch (ClientProtocolException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- } finally {
- try {
- httpclient.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }
- }
本实例是采用HttpClient4.3最新版本。该版本与之前的代码写法风格相差较大,大家多留意下。
参考:http://blog.csdn.net/wangpeng047/article/details/19624529
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