1.使用HttpClient发送请求、接收响应很简单，一般需要如下几步即可。
1. 创建HttpClient对象。
2. 创建请求方法的实例，并指定请求URL。如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。
3. 如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。
4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求，该方法返回一个HttpResponse。
5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头；调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。
6. 释放连接。无论执行方法是否成功，都必须释放连接
demo：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.log4j.Logger;
import com.mangocity.ziwoyou.bean.View;
import com.mangocity.ziwoyou.bean.ViewInfo;
public class ZiWoYouBaseService {
protected final Logger log = Logger.getLogger(getClass());
private String custId = null;
private String apikey = null;
private String serverHost = null;
public String call (Map<String , String> bodyMap,String serviceName) throws Exception {
String responseData = null;
Map<String,String> map=new HashMap<String,String>();
map.put("custId", getCustId());
map.put("apiKey", getApikey());
map.put("serverHost", getServerHost());
map.put("serviceName", serviceName);
responseData = get(bodyMap , map);
System.out.println("响应json：\n"+responseData);
return responseData;
}
/**
* 发送 get请求
*/
public static String get(Map<String , String> bodyMap, Map<String,String> map) {
HttpClient httpclient = new DefaultHttpClient();
String responseContent = null;
BufferedReader in = null;
try {
String custId = map.get("custId");
String apikey = map.get("apikey");
String serverHost = map.get("serverHost");
String serviceName = map.get("serviceName");
List<NameValuePair> qparams = dealRequestBody(bodyMap, custId,
apikey);
HttpResponse response = sendGet(httpclient, serverHost,
serviceName, qparams);
in = new BufferedReader(new InputStreamReader(response.getEntity()
.getContent()));
StringBuffer sb = new StringBuffer("");
String line = "";
while ((line = in.readLine()) != null) {
sb.append(line);
}
in.close();
responseContent = sb.toString();
System.out.println(responseContent);
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (URISyntaxException e) {
e.printStackTrace();
} finally{
try{
if(in!=null){
in.close();
}
}
catch(IOException ex){
ex.printStackTrace();
}
}
return responseContent;
}
/**
* 发送http get请求
* @param httpclient
* @param serverHost
* @param serviceName
* @param qparams
* @return
* @throws URISyntaxException
* @throws IOException
* @throws ClientProtocolException
*/
private static HttpResponse sendGet(HttpClient httpclient,
String serverHost, String serviceName, List<NameValuePair> qparams)
throws URISyntaxException, IOException, ClientProtocolException {
URI uri = URIUtils.createURI("http", serverHost, -1, serviceName,URLEncodedUtils.format(qparams, "UTF-8"), null);
HttpGet httpget = new HttpGet();
httpget.setURI(uri);
System.out.println(httpget.getURI());
HttpResponse response = httpclient.execute(httpget);
return response;
}
/**
* 处理请求参数
* @param bodyMap
* @param custId
* @param apikey
* @return
*/
private static List<NameValuePair> dealRequestBody(
Map<String, String> bodyMap, String custId, String apikey) {
List<NameValuePair> qparams = new ArrayList<NameValuePair>();
qparams.add(new BasicNameValuePair("custId", custId));
qparams.add(new BasicNameValuePair("apikey", apikey));
Iterator<Map.Entry<String, String>> iter = bodyMap.entrySet().iterator();
while(iter.hasNext()){
Entry<String , String> entry = iter.next();
String key = entry.getKey();
String value = entry.getValue();
qparams.add(new BasicNameValuePair(key, value));
}
return qparams;
}
public String getApikey() {
return apikey;
}
public void setApikey(String apikey) {
this.apikey = apikey;
}
public String getCustId() {
return custId;
}
public void setCustId(String custId) {
this.custId = custId;
}
public String getServerHost() {
return serverHost;
}
public void setServerHost(String serverHost) {
this.serverHost = serverHost;
}
public static void main(String[] args) {
Map bodyMap = new HashMap();
Map map = new HashMap();
map.put("custId", "***");
map.put("apikey", "********");
map.put("serverHost", "*******");
map.put("serviceName", "****");
bodyMap.put("cityName", "北京,上海,广州");
bodyMap.put("limit", "5");
String responseData = get(bodyMap , map);//获取到的数据为xml
ParseUtil<View> imageListDataParseUtil = new ParseUtil<View>();//转换xml数据
View view = imageListDataParseUtil.xmlToObject(responseData,View.class);
for (ViewInfo vi : view.getViews()) {
System.out.println(vi.getCityName());
}
}
}
参考链接：https://svn.apache.org/repos/asf/httpcomponents/httpclient/tags/4.1.1/httpclient-contrib/docs/translated-tutorial/httpclient-tutorial-simplified-chinese.pdf