JDK中提供了一些對無狀態協議請求（HTTP）的支援，下面我就將我所寫的一個小例子（元件）進行描述：

首先讓我們先構建一個請求類（HttpRequester）。

該類封裝了JAVA實現簡單請求的程式碼，如下：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.Map;
import java.util.Vector;
 
/**
 * HTTP請求物件
 * 
 * @author YYmmiinngg
 */
public class HttpRequester {
	private String defaultContentEncoding;
 
	public HttpRequester() {
		this.defaultContentEncoding = Charset.defaultCharset().name();
	}
 
	/**
	 * 傳送GET請求
	 * 
	 * @param urlString
	 *            URL地址
	 * @return 響應物件
	 * @throws IOException
	 */
	public HttpRespons sendGet(String urlString) throws IOException {
		return this.send(urlString, "GET", null, null);
	}
 
	/**
	 * 傳送GET請求
	 * 
	 * @param urlString
	 *            URL地址
	 * @param params
	 *            引數集合
	 * @return 響應物件
	 * @throws IOException
	 */
	public HttpRespons sendGet(String urlString, Map<String, String> params)
			throws IOException {
		return this.send(urlString, "GET", params, null);
	}
 
	/**
	 * 傳送GET請求
	 * 
	 * @param urlString
	 *            URL地址
	 * @param params
	 *            引數集合
	 * @param propertys
	 *            請求屬性
	 * @return 響應物件
	 * @throws IOException
	 */
	public HttpRespons sendGet(String urlString, Map<String, String> params,
			Map<String, String> propertys) throws IOException {
		return this.send(urlString, "GET", params, propertys);
	}
 
	/**
	 * 傳送POST請求
	 * 
	 * @param urlString
	 *            URL地址
	 * @return 響應物件
	 * @throws IOException
	 */
	public HttpRespons sendPost(String urlString) throws IOException {
		return this.send(urlString, "POST", null, null);
	}
 
	/**
	 * 傳送POST請求
	 * 
	 * @param urlString
	 *            URL地址
	 * @param params
	 *            引數集合
	 * @return 響應物件
	 * @throws IOException
	 */
	public HttpRespons sendPost(String urlString, Map<String, String> params)
			throws IOException {
		return this.send(urlString, "POST", params, null);
	}
 
	/**
	 * 傳送POST請求
	 * 
	 * @param urlString
	 *            URL地址
	 * @param params
	 *            引數集合
	 * @param propertys
	 *            請求屬性
	 * @return 響應物件
	 * @throws IOException
	 */
	public HttpRespons sendPost(String urlString, Map<String, String> params,
			Map<String, String> propertys) throws IOException {
		return this.send(urlString, "POST", params, propertys);
	}
 
	/**
	 * 傳送HTTP請求
	 * 
	 * @param urlString
	 * @return 響映物件
	 * @throws IOException
	 */
	private HttpRespons send(String urlString, String method,
			Map<String, String> parameters, Map<String, String> propertys)
			throws IOException {
		HttpURLConnection urlConnection = null;
 
		if (method.equalsIgnoreCase("GET") && parameters != null) {
			StringBuffer param = new StringBuffer();
			int i = 0;
			for (String key : parameters.keySet()) {
				if (i == 0)
					param.append("?");
				else
					param.append("&");
				param.append(key).append("=").append(parameters.get(key));
				i++;
			}
			urlString += param;
		}
		URL url = new URL(urlString);
		urlConnection = (HttpURLConnection) url.openConnection();
 
		urlConnection.setRequestMethod(method);
		urlConnection.setDoOutput(true);
		urlConnection.setDoInput(true);
		urlConnection.setUseCaches(false);
 
		if (propertys != null)
			for (String key : propertys.keySet()) {
				urlConnection.addRequestProperty(key, propertys.get(key));
			}
 
		if (method.equalsIgnoreCase("POST") && parameters != null) {
			StringBuffer param = new StringBuffer();
			for (String key : parameters.keySet()) {
				param.append("&");
				param.append(key).append("=").append(parameters.get(key));
			}
			urlConnection.getOutputStream().write(param.toString().getBytes());
			urlConnection.getOutputStream().flush();
			urlConnection.getOutputStream().close();
		}
 
		return this.makeContent(urlString, urlConnection);
	}
 
	/**
	 * 得到響應物件
	 * 
	 * @param urlConnection
	 * @return 響應物件
	 * @throws IOException
	 */
	private HttpRespons makeContent(String urlString,
			HttpURLConnection urlConnection) throws IOException {
		HttpRespons httpResponser = new HttpRespons();
		try {
			InputStream in = urlConnection.getInputStream();
			BufferedReader bufferedReader = new BufferedReader(
					new InputStreamReader(in));
			httpResponser.contentCollection = new Vector<String>();
			StringBuffer temp = new StringBuffer();
			String line = bufferedReader.readLine();
			while (line != null) {
				httpResponser.contentCollection.add(line);
				temp.append(line).append("\r\n");
				line = bufferedReader.readLine();
			}
			bufferedReader.close();
 
			String ecod = urlConnection.getContentEncoding();
			if (ecod == null)
				ecod = this.defaultContentEncoding;
 
			httpResponser.urlString = urlString;
 
			httpResponser.defaultPort = urlConnection.getURL().getDefaultPort();
			httpResponser.file = urlConnection.getURL().getFile();
			httpResponser.host = urlConnection.getURL().getHost();
			httpResponser.path = urlConnection.getURL().getPath();
			httpResponser.port = urlConnection.getURL().getPort();
			httpResponser.protocol = urlConnection.getURL().getProtocol();
			httpResponser.query = urlConnection.getURL().getQuery();
			httpResponser.ref = urlConnection.getURL().getRef();
			httpResponser.userInfo = urlConnection.getURL().getUserInfo();
 
			httpResponser.content = new String(temp.toString().getBytes(), ecod);
			httpResponser.contentEncoding = ecod;
			httpResponser.code = urlConnection.getResponseCode();
			httpResponser.message = urlConnection.getResponseMessage();
			httpResponser.contentType = urlConnection.getContentType();
			httpResponser.method = urlConnection.getRequestMethod();
			httpResponser.connectTimeout = urlConnection.getConnectTimeout();
			httpResponser.readTimeout = urlConnection.getReadTimeout();
 
			return httpResponser;
		} catch (IOException e) {
			throw e;
		} finally {
			if (urlConnection != null)
				urlConnection.disconnect();
		}
	}
 
	/**
	 * 預設的響應字符集
	 */
	public String getDefaultContentEncoding() {
		return this.defaultContentEncoding;
	}
 
	/**
	 * 設定預設的響應字符集
	 */
	public void setDefaultContentEncoding(String defaultContentEncoding) {
		this.defaultContentEncoding = defaultContentEncoding;
	}
}
 

其次我們來看看響應物件（HttpRespons）。響應物件其實只是一個數據BEAN，由此來封裝請求響應的結果資料，如下：

import java.util.Vector;
 
/**
 * 響應物件
 */
public class HttpRespons {
 
	String urlString;
 
	int defaultPort;
 
	String file;
 
	String host;
 
	String path;
 
	int port;
 
	String protocol;
 
	String query;
 
	String ref;
 
	String userInfo;
 
	String contentEncoding;
 
	String content;
 
	String contentType;
 
	int code;
 
	String message;
 
	String method;
 
	int connectTimeout;
 
	int readTimeout;
 
	Vector<String> contentCollection;
 
	public String getContent() {
		return content;
	}
 
	public String getContentType() {
		return contentType;
	}
 
	public int getCode() {
		return code;
	}
 
	public String getMessage() {
		return message;
	}
 
	public Vector<String> getContentCollection() {
		return contentCollection;
	}
 
	public String getContentEncoding() {
		return contentEncoding;
	}
 
	public String getMethod() {
		return method;
	}
 
	public int getConnectTimeout() {
		return connectTimeout;
	}
 
	public int getReadTimeout() {
		return readTimeout;
	}
 
	public String getUrlString() {
		return urlString;
	}
 
	public int getDefaultPort() {
		return defaultPort;
	}
 
	public String getFile() {
		return file;
	}
 
	public String getHost() {
		return host;
	}
 
	public String getPath() {
		return path;
	}
 
	public int getPort() {
		return port;
	}
 
	public String getProtocol() {
		return protocol;
	}
 
	public String getQuery() {
		return query;
	}
 
	public String getRef() {
		return ref;
	}
 
	public String getUserInfo() {
		return userInfo;
	}
 
}
 

最後，讓我們寫一個應用類，測試以上程式碼是否正確

import com.yao.http.HttpRequester;
import com.yao.http.HttpRespons;
 
public class Test {
	public static void main(String[] args) {
		try {
			HttpRequester request = new HttpRequester();
			HttpRespons hr = request.sendGet("http://www.csdn.net");
 
			System.out.println(hr.getUrlString());
			System.out.println(hr.getProtocol());
			System.out.println(hr.getHost());
			System.out.println(hr.getPort());
			System.out.println(hr.getContentEncoding());
			System.out.println(hr.getMethod());
			
			System.out.println(hr.getContent());
 
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}