微信网页授权获取用户基本信息

@WebServlet("/wx_token")
public class wx_token extends HttpServlet {
	private static final long serialVersionUID = 1L;
	public String token = "xxx";

	public wx_token() {
		super();
	}

	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		String signature = request.getParameter("signature");
		String timestamp = request.getParameter("timestamp");
		String nonce = request.getParameter("nonce");
		String echostr = request.getParameter("echostr");
		System.out.println("signature:" + signature);
		System.out.println("timestamp:" + timestamp);
		System.out.println("nonce:" + nonce);
		System.out.println("echostr:" + echostr);
		PrintWriter pw = response.getWriter();
		pw.append(echostr);
		pw.flush();
	}

}

@WebServlet("/OpenIdServlet")
public class OpenIdServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	private String openidURL = "https://open.weixin.qq.com/connect/oauth2/authorize?appid=%s&redirect_uri=%s&response_type=code&scope=snsapi_userinfo&state=123#wechat_redirect";
	private String appId = "您的appId";
	private String redirectURL = "http://10ec6069.ngrok.natapp.cn/OpenIdResultServlet";

	public OpenIdServlet() {
		super();
	}

	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		String url = String.format(openidURL, appId, redirectURL);
		response.sendRedirect(url);
	}

	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

@WebServlet("/OpenIdResultServlet")
public class OpenIdResultServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
	private String appId = "您的appId";
	private String appSecret = "您的appSecret";
	/**
	 * @see HttpServlet#HttpServlet()
	 */
	public OpenIdResultServlet() {
		super();
	}

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		String code = request.getParameter("code");
		String url = "https://api.weixin.qq.com/sns/oauth2/access_token";
		String params = "appid=" + appId + "&secret=" + appSecret + "&code="
				+ code + "&grant_type=authorization_code";
		// request.setAttribute("code", url + "?" + params);
		String s = HttpRequest.sendGet(url, params);
		request.setAttribute("code", s);
		try {
			JSONObject jsonObject = new JSONObject(s);
			String openid = jsonObject.getString("openid");
			request.setAttribute("code", "openid:" + openid);
		} catch (JSONException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		request.getRequestDispatcher("result.jsp").forward(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

public class HttpRequest {
	/**
	 * 向指定URL发送GET方法的请求
	 * 
	 * @param url
	 *            发送请求的URL
	 * @param param
	 *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
	 * @return URL 所代表远程资源的响应结果
	 */
	public static String sendGet(String url, String param) {
		String result = "";
		BufferedReader in = null;
		try {
			String urlNameString = url + "?" + param;
			URL realUrl = new URL(urlNameString);
			// 打开和URL之间的连接
			URLConnection connection = realUrl.openConnection();
			// 设置通用的请求属性
			connection.setRequestProperty("accept", "*/*");
			connection.setRequestProperty("connection", "Keep-Alive");
			connection.setRequestProperty("user-agent",
					"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			// 建立实际的连接
			connection.connect();
			// 获取所有响应头字段
			Map<String, List<String>> map = connection.getHeaderFields();
			// 遍历所有的响应头字段
			for (String key : map.keySet()) {
				System.out.println(key + "--->" + map.get(key));
			}
			// 定义 BufferedReader输入流来读取URL的响应
			in = new BufferedReader(new InputStreamReader(
					connection.getInputStream()));
			String line;
			while ((line = in.readLine()) != null) {
				result += line;
			}
		} catch (Exception e) {
			System.out.println("发送GET请求出现异常！" + e);
			e.printStackTrace();
		}
		// 使用finally块来关闭输入流
		finally {
			try {
				if (in != null) {
					in.close();
				}
			} catch (Exception e2) {
				e2.printStackTrace();
			}
		}
		return result;
	}

	/**
	 * 向指定 URL 发送POST方法的请求
	 * 
	 * @param url
	 *            发送请求的 URL
	 * @param param
	 *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
	 * @return 所代表远程资源的响应结果
	 */
	public static String sendPost(String url, String param) {
		PrintWriter out = null;
		BufferedReader in = null;
		String result = "";
		try {
			URL realUrl = new URL(url);
			// 打开和URL之间的连接
			URLConnection conn = realUrl.openConnection();
			// 设置通用的请求属性
			conn.setRequestProperty("accept", "*/*");
			conn.setRequestProperty("connection", "Keep-Alive");
			conn.setRequestProperty("user-agent",
					"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
			// 发送POST请求必须设置如下两行
			conn.setDoOutput(true);
			conn.setDoInput(true);
			// 获取URLConnection对象对应的输出流
			out = new PrintWriter(conn.getOutputStream());
			// 发送请求参数
			out.print(param);
			// flush输出流的缓冲
			out.flush();
			// 定义BufferedReader输入流来读取URL的响应
			in = new BufferedReader(
					new InputStreamReader(conn.getInputStream()));
			String line;
			while ((line = in.readLine()) != null) {
				result += line;
			}
		} catch (Exception e) {
			System.out.println("发送 POST 请求出现异常！" + e);
			e.printStackTrace();
		}
		// 使用finally块来关闭输出流、输入流
		finally {
			try {
				if (out != null) {
					out.close();
				}
				if (in != null) {
					in.close();
				}
			} catch (IOException ex) {
				ex.printStackTrace();
			}
		}
		return result;
	}
}