java HttpClicent網絡請求與解析

　　HttpClicent是Apache下的一個子項目，文檔齊全，詳見官網：http://hc.apache.org/httpcomponents-client-4.5.x/quickstart.html

　　這里列出一些常見用法：

　　　　（1）使用步驟：

　　　　　　1. 創建HttpClient對象。

　　　　　　2. 創建請求方法的實例，並指定請求URL。如果需要發送GET請求，創建HttpGet對象；如果需要發送POST請求，創建HttpPost對象。

　　　　　　3. 如果需要發送請求參數，可調用HttpGet、HttpPost共同的setParams(HetpParams params)方法來添加請求參數；對於HttpPost對象而言，也可調用setEntity(HttpEntity entity)方法來設置請求參數。

　　　　　　4. 調用HttpClient對象的execute(HttpUriRequest request)發送請求，該方法返回一個HttpResponse。

　　　　　　5. 調用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可獲取服務器的響應頭；調用HttpResponse的getEntity()方法可獲取HttpEntity對象，該對象包裝了服務器的響應內容。程序可通過該對象獲取服務器的響應內容。

　　　　　　6. 釋放連接。無論執行方法是否成功，都必須釋放連接

　　　　（2）官網示例：CloseableHttpClient httpclient = HttpClients.createDefault();HttpGet httpGet = new HttpGet("http://targethost/homepage");

CloseableHttpResponse response1 = httpclient.execute(httpGet); // The underlying HTTP connection is still held by the response object // to allow the response content to be streamed directly from the network socket. // In order to ensure correct deallocation of system resources // the user MUST call CloseableHttpResponse#close() from a finally clause. // Please note that if response content is not fully consumed the underlying // connection cannot be safely re-used and will be shut down and discarded // by the connection manager.  try { System.out.println(response1.getStatusLine()); HttpEntity entity1 = response1.getEntity(); // do something useful with the response body // and ensure it is fully consumed  EntityUtils.consume(entity1); } finally { response1.close(); } HttpPost httpPost = new HttpPost("http://targethost/login"); List <NameValuePair> nvps = new ArrayList <NameValuePair>(); nvps.add(new BasicNameValuePair("username", "vip")); nvps.add(new BasicNameValuePair("password", "secret")); httpPost.setEntity(new UrlEncodedFormEntity(nvps)); CloseableHttpResponse response2 = httpclient.execute(httpPost); try { System.out.println(response2.getStatusLine()); HttpEntity entity2 = response2.getEntity(); // do something useful with the response body // and ensure it is fully consumed  EntityUtils.consume(entity2); } finally { response2.close(); }

　　（3）解析結果：
　　　　1.返回時JSON:

     　　　　 List<NameValuePair> nvps = new ArrayList<NameValuePair>();
            nvps.add(new BasicNameValuePair("loginname","ss"));
            nvps.add(new BasicNameValuePair("password", "s123"));
            hp.setEntity(new UrlEncodedFormEntity(nvps));
            HttpResponse res = client.execute(hp);
            html = EntityUtils.toString(res.getEntity());

　　　　　　　　JSONObject obj = JSON.parseObject(html);//這里用了fastjson，把String類型的html轉換成JSON對象，若有多個，可轉換成數組
　　　　　　　　Iterator it = obj.keySet().iterator();
　　　　　　　　while(it.hasNext()){
　　　　　　　　　　String key = it.next().toString();
　　　　　　　　　　if(key.equals("Success")){
　　　　　　　　　　html = obj.get(key).toString();
　　　　　　　　　　}
　　　　　　　　}

　　　　2.返回html:　　

　　　　　　　 HttpGet hg = new HttpGet(course_list_url);
            HttpResponse res = client.execute(hg);
            html = EntityUtils.toString(res.getEntity());
            Document doc = Jsoup.parse(html);//這里用了Jsoup抓取需要的html代碼
            Element content = doc.getElementById("col-sm-5");
            Elements links = content.getElementsByTag("a");
            for (Element link : links) {
              String linkHref = link.attr("href");
              String linkText = link.text();
            }
            String courseId = "";
            Elements courseIds = doc.select("div.overflow-h>a[href]");
            Elements courseTimes = doc.select("h3.heading-xs>a");

　　　　（4）其他關於HttoClicent相關例子：

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() {
        get();
    }

    /**
     * HttpClient連接SSL
     */
    public void ssl() {
        CloseableHttpClient httpclient = null;
        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
            FileInputStream instream = new FileInputStream(new File("d:\\tomcat.keystore"));
            try {
                // 加載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和所有自簽名的證書
            SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore, new TrustSelfSignedStrategy()).build();
            // 只允許使用TLSv1協議
            SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[] { "TLSv1" }, null,
                    SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
            httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();
            // 創建http請求(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();
                }
            }
        }
    }

    /**
     * post方式提交表單（模擬用戶登錄請求）
     */
    public void postForm() {
        // 創建默認的httpClient實例.  
        CloseableHttpClient httpclient = HttpClients.createDefault();
        // 創建httppost  
        HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");
        // 創建參數隊列  
        List<namevaluepair> formparams = new ArrayList<namevaluepair>();
        formparams.add(new BasicNameValuePair("username", "admin"));
        formparams.add(new BasicNameValuePair("password", "123456"));
        UrlEncodedFormEntity uefEntity;
        try {
            uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");
            httppost.setEntity(uefEntity);
            System.out.println("executing request " + httppost.getURI());
            CloseableHttpResponse response = httpclient.execute(httppost);
            try {
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                    System.out.println("--------------------------------------");
                    System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8"));
                    System.out.println("--------------------------------------");
                }
            } finally {
                response.close();
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e1) {
            e1.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 關閉連接,釋放資源  
            try {
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 發送 post請求訪問本地應用並根據傳遞參數不同返回不同結果
     */
    public void post() {
        // 創建默認的httpClient實例.  
        CloseableHttpClient httpclient = HttpClients.createDefault();
        // 創建httppost  
        HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");
        // 創建參數隊列  
        List<namevaluepair> formparams = new ArrayList<namevaluepair>();
        formparams.add(new BasicNameValuePair("type", "house"));
        UrlEncodedFormEntity uefEntity;
        try {
            uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");
            httppost.setEntity(uefEntity);
            System.out.println("executing request " + httppost.getURI());
            CloseableHttpResponse response = httpclient.execute(httppost);
            try {
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                    System.out.println("--------------------------------------");
                    System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8"));
                    System.out.println("--------------------------------------");
                }
            } finally {
                response.close();
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e1) {
            e1.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 關閉連接,釋放資源  
            try {
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 發送 get請求
     */
    public void get() {
        CloseableHttpClient httpclient = HttpClients.createDefault();
        try {
            // 創建httpget.  
            HttpGet httpget = new HttpGet("http://www.baidu.com/");
            System.out.println("executing request " + httpget.getURI());
            // 執行get請求.  
            CloseableHttpResponse response = httpclient.execute(httpget);
            try {
                // 獲取響應實體  
                HttpEntity entity = response.getEntity();
                System.out.println("--------------------------------------");
                // 打印響應狀態  
                System.out.println(response.getStatusLine());
                if (entity != null) {
                    // 打印響應內容長度  
                    System.out.println("Response content length: " + entity.getContentLength());
                    // 打印響應內容  
                    System.out.println("Response content: " + EntityUtils.toString(entity));
                }
                System.out.println("------------------------------------");
            } finally {
                response.close();
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (ParseException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 關閉連接,釋放資源  
            try {
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 上傳文件
     */
    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();
            }
        }
    }
}</namevaluepair></namevaluepair></namevaluepair></namevaluepair>