Java實現HTTP的GET請求示例：

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.ConnectException;
import java.net.URL;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import net.sf.json.JSONException;
import net.sf.json.JSONObject;

/**
 * 公眾平臺通用介面工具類
 */
public class WeixinUtil {
	
	/**
	 * 發起https請求並獲取結果
	 * 
	 * @param requestUrl 請求地址
	 * @param requestMethod 請求方式（GET、POST）
	 * @param outputStr 提交的資料
	 * @return JSONObject(通過JSONObject.get(key)的方式獲取json物件的屬性值)
	 */
	public static JSONObject httpRequest(String requestUrl, String requestMethod, String outputStr) {
		JSONObject jsonObject = null;
		StringBuffer buffer = new StringBuffer();
		try {
			// 建立SSLContext物件，並使用我們指定的信任管理器初始化
			TrustManager[] tm = { new MyX509TrustManager() };
			SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");
			sslContext.init(null, tm, new java.security.SecureRandom());
			// 從上述SSLContext物件中得到SSLSocketFactory物件
			SSLSocketFactory ssf = sslContext.getSocketFactory();

			URL url = new URL(requestUrl);
			HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();
			httpUrlConn.setSSLSocketFactory(ssf);

			httpUrlConn.setDoOutput(true);
			httpUrlConn.setDoInput(true);
			httpUrlConn.setUseCaches(false);
			// 設定請求方式（GET/POST）
			httpUrlConn.setRequestMethod(requestMethod);

			if ("GET".equalsIgnoreCase(requestMethod))
				httpUrlConn.connect();

			// 當有資料需要提交時
			if (null != outputStr) {
				OutputStream outputStream = httpUrlConn.getOutputStream();
				// 注意編碼格式，防止中文亂碼
				outputStream.write(outputStr.getBytes("UTF-8"));
				outputStream.close();
			}

			// 將返回的輸入流轉換成字串
			InputStream inputStream = httpUrlConn.getInputStream();
			InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
			BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

			String str = null;
			while ((str = bufferedReader.readLine()) != null) {
				buffer.append(str);
			}
			bufferedReader.close();
			inputStreamReader.close();
			// 釋放資源
			inputStream.close();
			inputStream = null;
			httpUrlConn.disconnect();
			jsonObject = JSONObject.fromObject(buffer.toString());
		} catch (ConnectException ce) {
			ce.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return jsonObject;
	}

	/**
	 * 獲取access_token
	 * 
	 * @param appid 憑證
	 * @param appsecret 金鑰
	 * @return
	 */
	public static String getAccessToken(String appid, String appsecret) {
		// 獲取公眾號access_token的連結
		String access_token = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET";

		String requestUrl = access_token.replace("APPID", appid).replace("APPSECRET", appsecret);
		
		JSONObject jsonObject = httpRequest(requestUrl, "GET", null);
		
		// 如果請求成功
		if (null != jsonObject) {
			try {
				return jsonObject.getString("access_token");
			} catch (JSONException e) {
			}
		}
		return null;
	}

	/**
	 * 獲取jsapi_ticket
	 * 
	 * @param appid 憑證
	 * @param appsecret 金鑰
	 * @return
	 */
	public static String getJsapiTicket(String accessToken) {
		// 獲取公眾號jsapi_ticket的連結
		String jsapi_ticket_url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=ACCESS_TOKEN&type=jsapi";
		if (accessToken != null) {
			String requestUrl = jsapi_ticket_url.replace("ACCESS_TOKEN", accessToken);
			// String requestUrl = access_token_url.replace("APPID",
			// appid).replace("APPSECRET", appsecret);
			JSONObject jsonObject = httpRequest(requestUrl, "GET", null);
			// 如果請求成功
			if (null != jsonObject) {
				try {
					return jsonObject.getString("ticket");
				} catch (JSONException e) {
				}
			}
		} else {
			System.out.println("*****token為空 獲取ticket失敗******");
		}

		return null;
	}
}
 

import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.X509TrustManager;

/**
 * 證書信任管理器（用於https請求）
 * 
 */
public class MyX509TrustManager implements X509TrustManager {

	public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
	}

	public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
	}

	public X509Certificate[] getAcceptedIssuers() {
		return null;
	}
}