OAuth2 - 第三方登录之微信登录

要使用微信登录，需要在微信开放平台去注册开发者资质，只能是企业类型用户。在注册之后会提供微信id和微信秘钥，此外还需要申请网站应用名称和域名地址。流程参考微信登录功能

一、生成微信登录的二维码

微信提供了生成二维码的固定地址，也提供了将二维码嵌入到自己页面的方式，这里采用前者。
第三方使用网站应用授权登录前请注意已获取相应网页授权作用域（scope=snsapi_login）。然后可以访问https://open.weixin.qq.com/connect/qrconnect这个地址来生成二维码，并且必须附带以下参数：

书写方法

@GetMapping("/login")
public String login(){
   String baseUrl = "https://open.weixin.qq.com/connect/qrconnect" +
		   "?appid=%s" +
		   "&redirect_uri=%s" +
		   "&response_type=code" +
		   "&scope=snsapi_login" +
		   "&state=%s" +
		   "#wechat_redirect";
	// 对回调地址进行编码 - 该地址在申请微信登录时配置
	String redirect_url = ConstantWxUtils.WX_OPEN_REDIRECT_URL;
	try{
		 redirect_url = URLEncoder.encode(redirect_url,"utf-8");
	}catch (Exception e){
		e.printStackTrace();
	}
	String url = String.format(
			baseUrl,
			ConstantWxUtils.WX_OPEN_APP_ID,  // 微信ID
			redirect_url,
			"lcy"
	);
	return "redirect:" + url;
}

二、回调方法

第一步会生成一个网页，里面有一个二维码。微信扫描二维码之后，就会跳转到设置的回调地址(方法)，我们需要在这个回调方法里处理业务逻辑（获取用户信息、保存用户信息等）。

/**
 * 授权登录之后的回调方法
 * @param code 临时票据
 */
@GetMapping("/callback")
public String callback(String code, String state){
	try {
		// 拿着code去请求微信的固定地址，得到access_token和openid
		String baseAccessTokenUrl = "https://api.weixin.qq.com/sns/oauth2/access_token" +
				"?appid=%s" +
				"&secret=%s" +
				"&code=%s" +
				"&grant_type=authorization_code";
		String accessTokenUrl = String.format(
				baseAccessTokenUrl,
				ConstantWxUtils.WX_OPEN_APP_ID,     // 微信id
				ConstantWxUtils.WX_OPEN_APP_SECRET, // 微信秘钥
				code
		);
		// 发送get请求 - 获取的结果是JSON字符串
		String accessTokenInfo = HttpClientUtils.get(accessTokenUrl);
		// 将字符串转换成Map对象，获取access_token和openid
		Gson gson = new Gson();
		HashMap mapAccessToken = gson.fromJson(accessTokenInfo, HashMap.class);
		String access_token = (String) mapAccessToken.get("access_token");
		String openid = (String) mapAccessToken.get("openid");
		// 根据openid查询是数据库中是否有相同微信数据
		User user = userService.getOpenIdUser(openid);
		// 获取用户信息
		if (user == null){
			String baseUserInfoUrl = "https://api.weixin.qq.com/sns/userinfo" +
					"?access_token=%s" +
					"&openid=%s";
			// 拼接两个参数
			String userInfoUrl = String.format(
					baseUserInfoUrl,
					access_token,
					openid
			);
			// 发送请求
			String userInfo = HttpClientUtils.get(userInfoUrl);
			// 转换成Map对象，并获取昵称、头像等信息
			HashMap userInfoMap = gson.fromJson(userInfo, HashMap.class);
			String nickname = (String) userInfoMap.get("nickname");
			String headimgurl = (String) userInfoMap.get("headimgurl");

			user = new User();
			user.setOpenid(openid);     // openId
			user.setNickname(nickname);	// 昵称
			user.setAvatar(headimgurl);	// 头像地址
			userService.save(user);   // 保存到数据库
		}
		// 生成Token字符串
		String jwtToken = JwtUtils.getJwtToken(user.getId(),user.getNickname());
		// 登录成功，返回到首页显示数据，将Token字符串传过去，前端获取即可使用
		return "redirect:http://localhost:3000?token=" + jwtToken;
	}catch (Exception e){
		e.printStackTrace();
	}
}

上面使用了一个HttpClientUtils工具来发送get请求，需要依赖commons-lang-2.6.jar、httpclient-4.3.2.jar、httpcore-4.3.1.jar、commons-io-2.4.jar这几个Jar包。HttpClient发送请求的代码，网上有很多，也可以自己封装。本例所用的源码如下：

public class HttpClientUtils {

	public static final int connTimeout=10000;
	public static final int readTimeout=10000;
	public static final String charset="UTF-8";
	private static HttpClient client = null;

	static {
		PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
		cm.setMaxTotal(128);
		cm.setDefaultMaxPerRoute(128);
		client = HttpClients.custom().setConnectionManager(cm).build();
	}

	public static String postParameters(String url, String parameterStr) throws ConnectTimeoutException, SocketTimeoutException, Exception{
		return post(url,parameterStr,"application/x-www-form-urlencoded",charset,connTimeout,readTimeout);
	}

	public static String postParameters(String url, String parameterStr,String charset, Integer connTimeout, Integer readTimeout) throws ConnectTimeoutException, SocketTimeoutException, Exception{
		return post(url,parameterStr,"application/x-www-form-urlencoded",charset,connTimeout,readTimeout);
	}

	public static String postParameters(String url, Map<String, String> params) throws ConnectTimeoutException,
			SocketTimeoutException, Exception {
		return postForm(url, params, null, connTimeout, readTimeout);
	}

	public static String postParameters(String url, Map<String, String> params, Integer connTimeout,Integer readTimeout) throws ConnectTimeoutException,
			SocketTimeoutException, Exception {
		return postForm(url, params, null, connTimeout, readTimeout);
	}

	public static String get(String url) throws Exception {
		return get(url, charset, null, null);
	}

	public static String get(String url, String charset) throws Exception {
		return get(url, charset, connTimeout, readTimeout);
	}

	/**
	 * 发送一个 Post 请求, 使用指定的字符集编码.
	 *
	 * @param url
	 * @param body RequestBody
	 * @param mimeType 例如 application/xml "application/x-www-form-urlencoded" a=1&b=2&c=3
	 * @param charset 编码
	 * @param connTimeout 建立链接超时时间,毫秒.
	 * @param readTimeout 响应超时时间,毫秒.
	 * @return ResponseBody, 使用指定的字符集编码.
	 * @throws ConnectTimeoutException 建立链接超时异常
	 * @throws SocketTimeoutException  响应超时
	 * @throws Exception
	 */
	public static String post(String url, String body, String mimeType,String charset, Integer connTimeout, Integer readTimeout)
			throws ConnectTimeoutException, SocketTimeoutException, Exception {
		HttpClient client = null;
		HttpPost post = new HttpPost(url);
		String result = "";
		try {
			if (StringUtils.isNotBlank(body)) {
				HttpEntity entity = new StringEntity(body, ContentType.create(mimeType, charset));
				post.setEntity(entity);
			}
			// 设置参数
			Builder customReqConf = RequestConfig.custom();
			if (connTimeout != null) {
				customReqConf.setConnectTimeout(connTimeout);
			}
			if (readTimeout != null) {
				customReqConf.setSocketTimeout(readTimeout);
			}
			post.setConfig(customReqConf.build());

			HttpResponse res;
			if (url.startsWith("https")) {
				// 执行 Https 请求.
				client = createSSLInsecureClient();
				res = client.execute(post);
			} else {
				// 执行 Http 请求.
				client = HttpClientUtils.client;
				res = client.execute(post);
			}
			result = IOUtils.toString(res.getEntity().getContent(), charset);
		} finally {
			post.releaseConnection();
			if (url.startsWith("https") && client != null&& client instanceof CloseableHttpClient) {
				((CloseableHttpClient) client).close();
			}
		}
		return result;
	}


	/**
	 * 提交form表单
	 *
	 * @param url
	 * @param params
	 * @param connTimeout
	 * @param readTimeout
	 * @return
	 * @throws ConnectTimeoutException
	 * @throws SocketTimeoutException
	 * @throws Exception
	 */
	public static String postForm(String url, Map<String, String> params, Map<String, String> headers, Integer connTimeout,Integer readTimeout) throws ConnectTimeoutException,
			SocketTimeoutException, Exception {

		HttpClient client = null;
		HttpPost post = new HttpPost(url);
		try {
			if (params != null && !params.isEmpty()) {
				List<NameValuePair> formParams = new ArrayList<NameValuePair>();
				Set<Entry<String, String>> entrySet = params.entrySet();
				for (Entry<String, String> entry : entrySet) {
					formParams.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
				}
				UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formParams, Consts.UTF_8);
				post.setEntity(entity);
			}

			if (headers != null && !headers.isEmpty()) {
				for (Entry<String, String> entry : headers.entrySet()) {
					post.addHeader(entry.getKey(), entry.getValue());
				}
			}
			// 设置参数
			Builder customReqConf = RequestConfig.custom();
			if (connTimeout != null) {
				customReqConf.setConnectTimeout(connTimeout);
			}
			if (readTimeout != null) {
				customReqConf.setSocketTimeout(readTimeout);
			}
			post.setConfig(customReqConf.build());
			HttpResponse res = null;
			if (url.startsWith("https")) {
				// 执行 Https 请求.
				client = createSSLInsecureClient();
				res = client.execute(post);
			} else {
				// 执行 Http 请求.
				client = HttpClientUtils.client;
				res = client.execute(post);
			}
			return IOUtils.toString(res.getEntity().getContent(), "UTF-8");
		} finally {
			post.releaseConnection();
			if (url.startsWith("https") && client != null
					&& client instanceof CloseableHttpClient) {
				((CloseableHttpClient) client).close();
			}
		}
	}




	/**
	 * 发送一个 GET 请求
	 *
	 * @param url
	 * @param charset
	 * @param connTimeout  建立链接超时时间,毫秒.
	 * @param readTimeout  响应超时时间,毫秒.
	 * @return
	 * @throws ConnectTimeoutException   建立链接超时
	 * @throws SocketTimeoutException   响应超时
	 * @throws Exception
	 */
	public static String get(String url, String charset, Integer connTimeout,Integer readTimeout)
			throws ConnectTimeoutException,SocketTimeoutException, Exception {

		HttpClient client = null;
		HttpGet get = new HttpGet(url);
		String result = "";
		try {
			// 设置参数
			Builder customReqConf = RequestConfig.custom();
			if (connTimeout != null) {
				customReqConf.setConnectTimeout(connTimeout);
			}
			if (readTimeout != null) {
				customReqConf.setSocketTimeout(readTimeout);
			}
			get.setConfig(customReqConf.build());

			HttpResponse res = null;

			if (url.startsWith("https")) {
				// 执行 Https 请求.
				client = createSSLInsecureClient();
				res = client.execute(get);
			} else {
				// 执行 Http 请求.
				client = HttpClientUtils.client;
				res = client.execute(get);
			}

			result = IOUtils.toString(res.getEntity().getContent(), charset);
		} finally {
			get.releaseConnection();
			if (url.startsWith("https") && client != null && client instanceof CloseableHttpClient) {
				((CloseableHttpClient) client).close();
			}
		}
		return result;
	}


	/**
	 * 从 response 里获取 charset
	 *
	 * @param ressponse
	 * @return
	 */
	@SuppressWarnings("unused")
	private static String getCharsetFromResponse(HttpResponse ressponse) {
		// Content-Type:text/html; charset=GBK
		if (ressponse.getEntity() != null  && ressponse.getEntity().getContentType() != null && ressponse.getEntity().getContentType().getValue() != null) {
			String contentType = ressponse.getEntity().getContentType().getValue();
			if (contentType.contains("charset=")) {
				return contentType.substring(contentType.indexOf("charset=") + 8);
			}
		}
		return null;
	}



	/**
	 * 创建 SSL连接
	 * @return
	 * @throws GeneralSecurityException
	 */
	private static CloseableHttpClient createSSLInsecureClient() throws GeneralSecurityException {
		try {
			SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, new TrustStrategy() {
				public boolean isTrusted(X509Certificate[] chain,String authType) throws CertificateException {
					return true;
				}
			}).build();

			SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext, new X509HostnameVerifier() {

				@Override
				public boolean verify(String arg0, SSLSession arg1) {
					return true;
				}

				@Override
				public void verify(String host, SSLSocket ssl)
						throws IOException {
				}

				@Override
				public void verify(String host, X509Certificate cert)
						throws SSLException {
				}

				@Override
				public void verify(String host, String[] cns,
								   String[] subjectAlts) throws SSLException {
				}

			});

			return HttpClients.custom().setSSLSocketFactory(sslsf).build();

		} catch (GeneralSecurityException e) {
			throw e;
		}
	}

	public static void main(String[] args) {
		try {
			String str= post("https://localhost:443/ssl/test.shtml","name=12&page=34","application/x-www-form-urlencoded", "UTF-8", 10000, 10000);
			//String str= get("https://localhost:443/ssl/test.shtml?name=12&page=34","GBK");
            /*Map map = new HashMap();
            map.put("name", "111");
            map.put("page", "222");
            String str= postForm("https://localhost:443/ssl/test.shtml",map,null, 10000, 10000);*/
			System.out.println(str);
		} catch (ConnectTimeoutException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SocketTimeoutException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}