【HttpClient】使用学习

2022-10-26 19:12:31

HttpClient使用学习

HttpClient Tutorial：http://hc.apache.org/httpcomponents-client-4.5.x/tutorial/html/index.html

HttpClient是Apache HttpComponents中的一部分，下载地址：http://hc.apache.org/

转载：https://www.cnblogs.com/yangchongxing/p/9191073.html

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1、简单的Get请求

package core;

import java.io.InputStream;

import java.nio.charset.Charset;

import org.apache.http.HttpEntity;

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

public class Test {

    public static void main(String[] args) throws Exception {

        CloseableHttpClient httpclient = HttpClients.createDefault();

        HttpGet httpget = new HttpGet("http://localhost/");

        CloseableHttpResponse response = httpclient.execute(httpget);

        int code = response.getStatusLine().getStatusCode();

        if (HttpStatus.SC_OK == code) {

            try {

                HttpEntity entity = response.getEntity();

                if (entity != null) {

                    InputStream inputStream = entity.getContent();

                    try {

                        Charset charset = Charset.forName("UTF-8");

                        int len = 0;

                        byte[] buf = new byte[2048];

                        while( (len = inputStream.read(buf)) != -1 ) {

                            System.out.print(new String(buf, 0, len, charset));

                        }

                    } finally {

                        inputStream.close();

                    }

                }

            } finally {

                response.close();

            }

        }

    }

}

2、文件上传

package com.yuanxingyuan.common.util;

import java.io.File;

import java.io.IOException;

import org.apache.http.HttpEntity;

import org.apache.http.HttpStatus;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.client.utils.HttpClientUtils;

import org.apache.http.entity.mime.MultipartEntityBuilder;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

/**

 * http client工具类

 * @author 杨崇兴

 *

 */

public class HttpClientUtil {

    public static String postFile(String url, File file) {

        String result = "";

        CloseableHttpClient httpClient = HttpClients.createDefault();

        CloseableHttpResponse response = null;

        MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();

        multipartEntityBuilder.addBinaryBody("file", file);

        HttpPost httpPost = new HttpPost(url);

        httpPost.setEntity(multipartEntityBuilder.build());

        try {

            response = httpClient.execute(httpPost);

            int statusCode = response.getStatusLine().getStatusCode();

            if (statusCode == HttpStatus.SC_OK) {

                HttpEntity entity = response.getEntity();

                result = EntityUtils.toString(entity);

                EntityUtils.consume(entity);

            }

        } catch (ClientProtocolException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        } finally {

            HttpClientUtils.closeQuietly(response);

            HttpClientUtils.closeQuietly(httpClient);

        }

        return result;

    }

    public static void main(String[] args) {

        String result = HttpClientUtil.postFile("http://localhost:8080/upload/image",new File("E:/wx/image.jpg"));

        System.out.println(result);

    }

}

服务端使用servlet3.0

import java.io.IOException;

import java.util.Collection;

import javax.servlet.ServletException;

import javax.servlet.annotation.MultipartConfig;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.Part;

import org.apache.catalina.core.ApplicationPart;

/**

 * Servlet implementation class Upload

 */

@WebServlet("/image")

@MultipartConfig

public class Upload extends HttpServlet {

    private static final long serialVersionUID = 1L;

    /**

     * @see HttpServlet#HttpServlet()

     */

    public Upload() {

        super();

        // TODO Auto-generated constructor stub

    }

    /**

     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doGet(request, response);

    }

    /**

     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

     */

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        Collection<Part> parts = request.getParts();

        if (parts != null) {

            for(Part part : parts){

                ApplicationPart ap= (ApplicationPart) part;

                String name = ap.getSubmittedFileName();

                part.write("E:/"+name);

                System.out.println("upload ok. " + name);

            }

        }

    }

}

package httpclient;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.List;

import org.apache.http.HttpEntity;

import org.apache.http.NameValuePair;

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.HttpPost;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.message.BasicNameValuePair;

public class Main {

    public static void main(String[] args) throws ClientProtocolException, IOException {

        //https://www.baidu.com/s?wd=%E8%A5%BF%E5%AE%89

        List<NameValuePair> params = new ArrayList<NameValuePair>();

        params.add(new BasicNameValuePair("name","西安"));

        HttpPost post = new HttpPost("http://www.baidu.com/s?wd=西安");

        UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(params);

        post.setEntity(urlEncodedFormEntity);

        CloseableHttpClient client = HttpClients.createDefault();

        CloseableHttpResponse response = client.execute(post);

        HttpEntity httpEntity = response.getEntity();

        InputStream inputStream = httpEntity.getContent();

        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));

        String line = "";

        while( (line = reader.readLine()) != null ) {

            System.out.println(line);

        }

        reader.close();

        response.close();

        client.close();

    }

}

3、请求配置

HttpGet httpGet = new HttpGet("http://localhost/demo/api/test/3");

RequestConfig config = RequestConfig.custom()

        .setSocketTimeout(10000)

        .setConnectTimeout(10000)

        .setConnectionRequestTimeout(10000)

        .build();

httpGet.setConfig(config);

4、拦截器

CloseableHttpClient httpClient = HttpClients.custom()

        .addInterceptorLast(new HttpRequestInterceptor(){

            @Override

            public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {

                String count = (String) context.getAttribute("count");

                request.addHeader("count", count);

            }

            }).build();

HttpGet httpGet = new HttpGet("http://localhost/demo/test/3");

RequestConfig config = RequestConfig.custom()

        .setSocketTimeout(10000)

        .setConnectTimeout(10000)

        .setConnectionRequestTimeout(10000)

        .build();

httpGet.setConfig(config);

HttpClientContext context = HttpClientContext.create();

context.setAttribute("count", "111");

CloseableHttpResponse httpResponse =  httpClient.execute(httpGet, context);

int code = httpResponse.getStatusLine().getStatusCode();

if (HttpStatus.SC_OK == code) {

    HttpEntity entity = httpResponse.getEntity();

    if (entity != null) {

        Charset charset = Charset.forName("UTF-8");

        System.out.println(EntityUtils.toString(entity, charset));

    }

}

httpResponse.close();

httpClient.close();

HttpClientBuilder addInterceptorFirst(final HttpResponseInterceptor itcp)
HttpClientBuilder addInterceptorFirst(final HttpRequestInterceptor itcp)
HttpClientBuilder addInterceptorLast(final HttpResponseInterceptor itcp)
HttpClientBuilder addInterceptorLast(final HttpRequestInterceptor itcp)

添加四种类型的拦截器

5、从链接管理获得链接

HttpClientContext context = HttpClientContext.create();

HttpClientConnectionManager manager = new BasicHttpClientConnectionManager();

HttpRoute route = new HttpRoute(new HttpHost("119.23.107.129", 80));

ConnectionRequest request = manager.requestConnection(route, null);

HttpClientConnection conn = request.get(10, TimeUnit.SECONDS);

if (conn.isOpen()) {

    manager.connect(conn, route, 1000, context);

    manager.routeComplete(conn, route, context);

    manager.releaseConnection(conn, null, 1, TimeUnit.MINUTES);

}

6、链接管理池

PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();

// Increase max total connection to 200

cm.setMaxTotal(200);

// Increase default max connection per route to 20

cm.setDefaultMaxPerRoute(20);

// Increase max connections for localhost:80 to 50

HttpHost localhost = new HttpHost("locahost", 80);

cm.setMaxPerRoute(new HttpRoute(localhost), 50);

CloseableHttpClient httpClient = HttpClients.custom()

        .setConnectionManager(cm)

        .build();

7、连接保持活着策略

ConnectionKeepAliveStrategy myStrategy = new ConnectionKeepAliveStrategy() {

    @Override

    public long getKeepAliveDuration(HttpResponse response, HttpContext context) {

        HeaderElementIterator it = new BasicHeaderElementIterator(response.headerIterator(HTTP.CONN_KEEP_ALIVE));

        while (it.hasNext()) {

            HeaderElement he = it.nextElement();

            String param = he.getName();

            String value = he.getValue();

            if (value != null && param.equalsIgnoreCase("timeout")) {

                try {

                    return Long.parseLong(value) * 1000;

                } catch(NumberFormatException ignore) {

                }

            }

        }

        HttpHost target = (HttpHost) context.getAttribute(

        HttpClientContext.HTTP_TARGET_HOST);

        if ("www.naughty-server.com".equalsIgnoreCase(target.getHostName())) {

            // Keep alive for 5 seconds only

            return 5 * 1000;

        } else {

            // otherwise keep alive for 30 seconds

            return 30 * 1000;

        }

    }};

CloseableHttpClient httpClient = HttpClients.custom().setKeepAliveStrategy(myStrategy).build();

8、SSL使用实例PKCS12证书

url 请求地址

xmlObj 发送xml数据

certKey 证书密钥

certPath 证书文件地址PKCS12证书

@SuppressWarnings("unchecked")

public static Map<String, String> httpsPostRequestCert(String url, String xmlObj, String certKey, String certPath) {

    Map<String, String> wxmap = new HashMap<String, String>();

    try {

        // 指定读取证书格式为PKCS12

        KeyStore keyStore = KeyStore.getInstance("PKCS12");

        // 读取本机存放的PKCS12证书文件

        FileInputStream instream = new FileInputStream(new File(certPath));

        // 指定PKCS12的密码(商户ID)

        keyStore.load(instream, certKey.toCharArray());

        instream.close();

        SSLContext sslcontext = SSLContexts.custom().loadKeyMaterial(keyStore, certKey.toCharArray()).build();

        SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[] {"TLSv1"}, null, SSLConnectionSocketFactory.getDefaultHostnameVerifier());

        CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(sslsf).build();

        HttpPost httpPost = new HttpPost(url);

        // 得指明使用UTF-8编码，否则到API服务器XML的中文不能被成功识别

        httpPost.addHeader("Content-Type", "text/xml");

        httpPost.setEntity(new StringEntity(xmlObj, "UTF-8"));

        // 根据默认超时限制初始化requestConfig

        RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(10000).setConnectTimeout(30000).build();

        // 设置请求器的配置

        httpPost.setConfig(requestConfig);

        HttpResponse response = null;

        try {

            response = httpClient.execute(httpPost);

        } catch (IOException e) {

            e.printStackTrace();

        }

        HttpEntity entity = response.getEntity();

        //转换为Map

        InputStream inputStream = entity.getContent();

        SAXReader reader = new SAXReader();

        Document document = reader.read(inputStream);

        Element root = document.getRootElement();

        List<Element> elementList = root.elements();

        for (Element e : elementList) {

            wxmap.put(e.getName(), e.getText());

        }

    }  catch (Exception e) {

        wxmap.put("return_msg", e.getMessage());

    }

    return wxmap;

}

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