apache httpclient 4 学习和例子

package com.eecn.warehouse.api.action;import java.util.regex.Matcher;import java.util.regex.Pattern;import org.apache.http.Header;import org.apache.http.HttpEntity;import org.apache.http.HttpHost;import org.apache.http.HttpResponse;import org.apache.http.HttpStatus;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.entity.ContentType;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.util.EntityUtils;public class HttpTest {    public final static void main(String[] args) throws Exception {         // 初始化，此处构造函数就与3.1中不同        HttpClient httpclient = new DefaultHttpClient();         HttpHost targetHost = new HttpHost("www.google.com.hk");        //HttpGet httpget = new HttpGet("http://www.apache.org/");        HttpGet httpget = new HttpGet("/");         // 查看默认request头部信息        System.out.println("Accept-Charset:" + httpget.getFirstHeader("Accept-Charset"));        // 以下这条如果不加会发现无论你设置Accept-Charset为gbk还是utf-8，他都会默认返回gb2312（本例针对google.cn来说）        httpget.setHeader("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.1.2)");        // 用逗号分隔显示可以同时接受多种编码        httpget.setHeader("Accept-Language", "zh-cn,zh;q=0.5");        httpget.setHeader("Accept-Charset", "GB2312,utf-8;q=0.7,*;q=0.7");        // 验证头部信息设置生效        System.out.println("Accept-Charset:" + httpget.getFirstHeader("Accept-Charset").getValue());         // Execute HTTP request        System.out.println("executing request " + httpget.getURI());        HttpResponse response = httpclient.execute(targetHost, httpget);        //HttpResponse response = httpclient.execute(httpget);         System.out.println("----------------------------------------");        System.out.println("Location: " + response.getLastHeader("Location"));        System.out.println(response.getStatusLine().getStatusCode());        System.out.println(response.getLastHeader("Content-Type"));        System.out.println(response.getLastHeader("Content-Length"));                System.out.println("----------------------------------------");         // 判断页面返回状态判断是否进行转向抓取新链接        int statusCode = response.getStatusLine().getStatusCode();        if ((statusCode == HttpStatus.SC_MOVED_PERMANENTLY) ||                (statusCode == HttpStatus.SC_MOVED_TEMPORARILY) ||                (statusCode == HttpStatus.SC_SEE_OTHER) ||                (statusCode == HttpStatus.SC_TEMPORARY_REDIRECT)) {            // 此处重定向处理  此处还未验证            String newUri = response.getLastHeader("Location").getValue();            httpclient = new DefaultHttpClient();            httpget = new HttpGet(newUri);            response = httpclient.execute(httpget);        }         // Get hold of the response entity        HttpEntity entity = response.getEntity();                // 查看所有返回头部信息        Header headers[] = response.getAllHeaders();        int ii = 0;        while (ii < headers.length) {            System.out.println(headers[ii].getName() + ": " + headers[ii].getValue());            ++ii;        }                // If the response does not enclose an entity, there is no need        // to bother about connection release        if (entity != null) {            // 将源码流保存在一个byte数组当中，因为可能需要两次用到该流，            byte[] bytes = EntityUtils.toByteArray(entity);            String charSet = "";                        // 如果头部Content-Type中包含了编码信息，那么我们可以直接在此处获取            charSet = ContentType.getOrDefault(entity).getCharset().name();             System.out.println("In header: " + charSet);            // 如果头部中没有，那么我们需要 查看页面源码，这个方法虽然不能说完全正确，因为有些粗糙的网页编码者没有在页面中写头部编码信息            if (charSet == "") {                String regEx = "(?=<meta).*?(?<=charset=[\\'|\\\"]?)([[a-z]|[A-Z]|[0-9]|-]*)";                Pattern p = Pattern.compile(regEx, Pattern.CASE_INSENSITIVE);                Matcher m = p.matcher(new String(bytes));  // 默认编码转成字符串，因为我们的匹配中无中文，所以串中可能的乱码对我们没有影响                boolean result = m.find();                System.out.println(result);                if (m.groupCount() == 1) {                    charSet = m.group(1);                } else {                    charSet = "";                }            }            System.out.println("Last get: " + charSet);            // 至此，我们可以将原byte数组按照正常编码专成字符串输出（如果找到了编码的话）            System.out.println("Encoding string is: " + new String(bytes, charSet));        }         httpclient.getConnectionManager().shutdown();            } }

下面是也是一个例子：

public static String sendRequest(String[] reqXml) {HttpPost httpPost = null;String rspXml = null;try {// 构造HttpClient的实例HttpClient httpClient = new DefaultHttpClient();// 设置连接超时httpClient.getParams().setIntParameter(HttpConnectionParams.CONNECTION_TIMEOUT, 10000);httpClient.getParams().setIntParameter(HttpConnectionParams.SO_TIMEOUT, 20000);httpClient.getParams().setParameter(CoreProtocolPNames.HTTP_CONTENT_CHARSET, "UTF-8");httpPost = new HttpPost(ApiAction.SERVER_URL);//httpPost.setHeader(HTTP.CONTENT_TYPE, "charset=UTF-8");httpPost.setHeader(HTTP.CONTENT_ENCODING, "UTF-8");httpPost.setHeader(HTTP.USER_AGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.1.2)");        // 用逗号分隔显示可以同时接受多种编码httpPost.setHeader("Accept-Language", "zh-cn,zh;q=0.5");httpPost.setHeader("Accept-Charset", "UTF-8;q=0.7,*;q=0.7");//参数List<NameValuePair> nameValuePairList = new ArrayList<NameValuePair>();nameValuePairList.add(new BasicNameValuePair("xml", reqXml[0]));nameValuePairList.add(new BasicNameValuePair("signature", reqXml[1]));// 将参数加入到请求方法中HttpEntity httpEntity = new UrlEncodedFormEntity(nameValuePairList, "UTF-8");httpPost.setEntity(httpEntity);// 发送连接HttpResponse httpResponse = httpClient.execute(httpPost);HttpEntity rspHttpEntity = httpResponse.getEntity();int statusCode = httpResponse.getStatusLine().getStatusCode();if (statusCode == HttpStatus.SC_OK) {rspXml = IOUtils.toString(rspHttpEntity.getContent());LOGGER.info("响应XML：" + rspXml);} else {LOGGER.error("http client 错误。错误码[" + statusCode + "]");}return rspXml;} catch (Exception e) {LOGGER.error("http client invoke error.", e);return null;} finally {if (httpPost != null) {httpPost.releaseConnection();}}}