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();
}
}
}