在微信公眾號請求使用者網頁授權之前，開發者需要先到公眾平臺官網中的開發者中心頁配置授權回撥域名。請注意，這裡填寫的是域名（是一個字串），而不是URL，因此請勿加 http:// 等協議頭。

（1）登陸微信公眾號後臺，點選許可權介面點修改如圖：

（2）修改如圖

配置時要下載個MP_verify_BZf0ox6nPYbl3Fdv.txt檔案放到授權web專案下，部署的時候放到webapps/weixinpt目錄下面。說明：是地址加專案名:本次是weixinpt舉例的

注意：redirect_uri地址必須urlencode處理

處理：這個地址是給微信公眾號的地址，要把地址裡面的紅色值換掉，你現在用的微信公眾號的appid的值。redirect_uri

程式碼實現：

<script type="text/javascript">
	
	 var ls_openid="";
	 function getopenid()
	 { 
	  var APPID='<%=APPID %>';
	  var SECRETID='<%=SECRETID %>';
	  var path = "<%=request.getContextPath() %>/OAuth2Service?code=<%=request.getParameter("code").toString()%>&appid="+APPID+"&secret="+SECRETID;
	 
	   $.ajaxSetup({  
	     async : false  
	  });
	   
      $.get(path,function(data){	  	 
	  	 ls_openid=data;
	  	 loginopenid(ls_openid);
	  });  
    
	 }
	  function loginopenid(ls_openid){
var url = "<%=request.getContextPath() %>/wxIdLonginAction.do?wxid="+ls_openid;
 window.location.href=url;
 
 }
	 </script>
 

<servlet>
	<servlet-name>OAuth</servlet-name>
	<servlet-class>cn.com.zhongway.im.wechat.OAuth</servlet-class>
</servlet>
<servlet-mapping>
	<servlet-name>OAuth</servlet-name>
	<url-pattern>/OAuth</url-pattern>
</servlet-mapping>
 

/***********************************************************************
 * Module:  PublicAction.java
 * Author:  Administrator
 * Purpose: Defines the Class PublicAction
 ***********************************************************************/

package cn.com.zhongway.im.wechat;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.log4j.Logger;
import com.sun.corba.se.spi.legacy.connection.Connection;
public class OAuth extends HttpServlet {


	/**
	 * 通過code換取網頁授權access_token，根據授權返回頁面獲取的code值獲取openid
	 */
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
	
		String wxCode = request.getParameter("code");
        String appid =  request.getParameter("appid");
        String secret = request.getParameter("secret");
        //第一次請求 獲取access_token 和 openid
        String requestUrl = "";
        String oppid="";
        JSONObject oppidObj =null;
        String access_token ="";
        String openid ="";
        String requestUrl2="";
        String userInfoStr="";
        JSONObject wxUserInfo=null;
		try {
			 //獲取code後，請求以下連結獲取access_token
			 requestUrl = "https://api.weixin.qq.com/sns/oauth2/access_token?appid="+appid+"&secret="+secret+"&code="+wxCode+"&grant_type=authorization_code";
			 oppid = new HttpRequestor().doGet(requestUrl);
			 oppidObj =JSONObject.fromObject(oppid);
			 //獲取access_token
	         access_token = (String) oppidObj.get("access_token");
	         //獲取openid
	         openid = (String) oppidObj.get("openid");
	         //測試輸出
	         request.setAttribute("openid", openid);
	        //response.getWriter().print("openid:"+openid);
	         //拉取使用者資訊(需scope為 snsapi_userinfo)就是微信平臺填的連結，
	         //scope：snsapi_base （不彈出授權頁面，直接跳轉，只能獲取使用者openid）
	         //snsapi_userinfo （彈出授權頁面，可通過openid拿到暱稱、性別、所在地。並且，即使在未關注的情況下，只要使用者授權，也能獲取其資訊）
             /*requestUrl2 = "https://api.weixin.qq.com/sns/userinfo?access_token="+access_token+"&openid="+openid+"&lang=zh_CN";
             userInfoStr = new HttpRequestor().doGet(requestUrl2);
             wxUserInfo =JSONObject.fromObject(userInfoStr);*/
             response.getWriter().print(openid);
             response.getWriter().flush();
		     response.getWriter().close();
	        
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
        
		

	}

	
	
	

	@Override
	public void destroy() {
		super.destroy();
	}

	@Override
	public void init() throws ServletException {
		super.init();
	}

	public boolean isChinese(String str) {
		boolean result = false;
		for (int i = 0; i < str.length(); i++) {
			int chr1 = (char) str.charAt(i);
			if (chr1 >= 19968 && chr1 <= 171941) {// 漢字範圍 \u4e00-\u9fa5 (中文)
				result = true;
			}
		}
		return result;
	}
	
	private Map pubErrorContent(Exception e,String id){
		Map errorcontent = new HashMap();
		String[] es = e.toString().split(":");
		String type = "";
		String keywords = "";
		String content = "";
		for(int i = 0 ; i < es.length ; i++){
			if(i==0){
				type = es[i];
			}
			if(i==1){
				keywords = es[i];
			}
			if(i==3){
				keywords = es[i];
			}
		}
		errorcontent.put("id", id);
		errorcontent.put("type", type);
		errorcontent.put("keywords", keywords);
		errorcontent.put("content", content);
		return errorcontent;
	}
	
	private Map pubInfoContent(String keywords,String info){
		return null;
	}
	
}

package cn.com.zhongway.im.wechat;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;
import java.util.Map;
/**
 *處理OAuth2Service類微信連結url的的工具類，自己能處理可以不呼叫
 */
public class HttpRequestor {
	 private String charset = "utf-8";
	    private Integer connectTimeout = null;
	    private Integer socketTimeout = null;
	    private String proxyHost = null;
	    private Integer proxyPort = null;
	 
	    /**
	     * Do GET request
	     *
	     * @param url
	     * @return
	     * @throws Exception
	     * @throws IOException
	     */
	    public String doGet(String url) throws Exception {
	 
	        URL localURL = new URL(url);
	 
	        URLConnection connection = openConnection(localURL);
	        HttpURLConnection httpURLConnection = (HttpURLConnection) connection;
	 
	        httpURLConnection.setRequestProperty("Accept-Charset", charset);
	        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
	 
	        InputStream inputStream = null;
	        InputStreamReader inputStreamReader = null;
	        BufferedReader reader = null;
	        StringBuffer resultBuffer = new StringBuffer();
	        String tempLine = null;
	 
	        if (httpURLConnection.getResponseCode() >= 300) {
	            throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
	        }
	 
	        try {
	            inputStream = httpURLConnection.getInputStream();
	            inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
	            reader = new BufferedReader(inputStreamReader);
	 
	            while ((tempLine = reader.readLine()) != null) {
	                resultBuffer.append(tempLine);
	            }
	 
	        } finally {
	 
	            if (reader != null) {
	                reader.close();
	            }
	 
	            if (inputStreamReader != null) {
	                inputStreamReader.close();
	            }
	 
	            if (inputStream != null) {
	                inputStream.close();
	            }
	 
	        }
	 
	        return resultBuffer.toString();
	    }
	 
	    /**
	     * Do POST request
	     *
	     * @param url
	     * @param parameterMap
	     * @return
	     * @throws Exception
	     */
	    public String doPost(String url, Map<?, ?> parameterMap) throws Exception {
	 
	        /* Translate parameter map to parameter date string */
	        StringBuffer parameterBuffer = new StringBuffer();
	        if (parameterMap != null) {
	            Iterator<?> iterator = parameterMap.keySet().iterator();
	            String key = null;
	            String value = null;
	            while (iterator.hasNext()) {
	                key = (String) iterator.next();
	                if (parameterMap.get(key) != null) {
	                    value = (String) parameterMap.get(key);
	                } else {
	                    value = "";
	                }
	 
	                parameterBuffer.append(key).append("=").append(value);
	                if (iterator.hasNext()) {
	                    parameterBuffer.append("&");
	                }
	            }
	        }
	 
	        System.out.println("POST parameter : " + parameterBuffer.toString());
	 
	        URL localURL = new URL(url);
	 
	        URLConnection connection = openConnection(localURL);
	        HttpURLConnection httpURLConnection = (HttpURLConnection) connection;
	 
	        httpURLConnection.setDoOutput(true);
	        httpURLConnection.setRequestMethod("POST");
	        httpURLConnection.setRequestProperty("Accept-Charset", charset);
	        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
	        httpURLConnection.setRequestProperty("Content-Length", String.valueOf(parameterBuffer.length()));
	 
	        OutputStream outputStream = null;
	        OutputStreamWriter outputStreamWriter = null;
	        InputStream inputStream = null;
	        InputStreamReader inputStreamReader = null;
	        BufferedReader reader = null;
	        StringBuffer resultBuffer = new StringBuffer();
	        String tempLine = null;
	 
	        try {
	            outputStream = httpURLConnection.getOutputStream();
	            outputStreamWriter = new OutputStreamWriter(outputStream);
	 
	            outputStreamWriter.write(parameterBuffer.toString());
	            outputStreamWriter.flush();
	 
	            if (httpURLConnection.getResponseCode() >= 300) {
	                throw new Exception("HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
	            }
	 
	            inputStream = httpURLConnection.getInputStream();
	            inputStreamReader = new InputStreamReader(inputStream);
	            reader = new BufferedReader(inputStreamReader);
	 
	            while ((tempLine = reader.readLine()) != null) {
	                resultBuffer.append(tempLine);
	            }
	 
	        } finally {
	 
	            if (outputStreamWriter != null) {
	                outputStreamWriter.close();
	            }
	 
	            if (outputStream != null) {
	                outputStream.close();
	            }
	 
	            if (reader != null) {
	                reader.close();
	            }
	 
	            if (inputStreamReader != null) {
	                inputStreamReader.close();
	            }
	 
	            if (inputStream != null) {
	                inputStream.close();
	            }
	 
	        }
	 
	        return resultBuffer.toString();
	    }
	 
	    private URLConnection openConnection(URL localURL) throws IOException {
	        URLConnection connection;
	        if (proxyHost != null && proxyPort != null) {
	            Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPort));
	            connection = localURL.openConnection(proxy);
	        } else {
	            connection = localURL.openConnection();
	        }
	        return connection;
	    }
	 
	    /*
	     * Getter & Setter
	     */
	    public Integer getConnectTimeout() {
	        return connectTimeout;
	    }
	 
	    public void setConnectTimeout(Integer connectTimeout) {
	        this.connectTimeout = connectTimeout;
	    }
	 
	    public Integer getSocketTimeout() {
	        return socketTimeout;
	    }
	 
	    public void setSocketTimeout(Integer socketTimeout) {
	        this.socketTimeout = socketTimeout;
	    }
	 
	    public String getProxyHost() {
	        return proxyHost;
	    }
	 
	    public void setProxyHost(String proxyHost) {
	        this.proxyHost = proxyHost;
	    }
	 
	    public Integer getProxyPort() {
	        return proxyPort;
	    }
	 
	    public void setProxyPort(Integer proxyPort) {
	        this.proxyPort = proxyPort;
	    }
	 
	    public String getCharset() {
	        return charset;
	    }
	 
	    public void setCharset(String charset) {
	        this.charset = charset;
	    }

}