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【HttpClient】使用学习

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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原文地址：https://www.cnblogs.com/yangchongxing/p/9191073.html