要使用微信登錄，需要在微信開放平臺去註冊開發者資質，只能是企業類型用戶。在註冊之後會提供微信id和微信祕鑰，此外還需要申請網站應用名稱和域名地址。流程參考微信登錄功能
一、生成微信登錄的二維碼
微信提供了生成二維碼的固定地址，也提供了將二維碼嵌入到自己頁面的方式，這裏採用前者。
第三方使用網站應用授權登錄前請注意已獲取相應網頁授權作用域（scope=snsapi_login）。然後可以訪問https://open.weixin.qq.com/connect/qrconnect這個地址來生成二維碼，並且必須附帶以下參數：
書寫方法
@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";
// 對回調地址進行編碼 - 該地址在申請微信登錄時配置
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、回調方法
第一步會生成一個網頁，裏面有一個二維碼。微信掃描二維碼之後，就會跳轉到設置的回調地址(方法)，我們需要在這個回調方法裏處理業務邏輯（獲取用戶信息、保存用戶信息等）。
/**
* 授權登錄之後的回調方法
* @param code 臨時票據
*/
@GetMapping("/callback")
public String callback(String code, String state){
try {
// 拿着code去請求微信的固定地址，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, // 微信祕鑰
code
);
// 發送get請求 - 獲取的結果是JSON字符串
String accessTokenInfo = HttpClientUtils.get(accessTokenUrl);
// 將字符串轉換成Map對象，獲取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");
// 根據openid查詢是數據庫中是否有相同微信數據
User user = userService.getOpenIdUser(openid);
// 獲取用戶信息
if (user == null){
String baseUserInfoUrl = "https://api.weixin.qq.com/sns/userinfo" +
"?access_token=%s" +
"&openid=%s";
// 拼接兩個參數
String userInfoUrl = String.format(
baseUserInfoUrl,
access_token,
openid
);
// 發送請求
String userInfo = HttpClientUtils.get(userInfoUrl);
// 轉換成Map對象，並獲取暱稱、頭像等信息
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); // 暱稱
user.setAvatar(headimgurl); // 頭像地址
userService.save(user); // 保存到數據庫
}
// 生成Token字符串
String jwtToken = JwtUtils.getJwtToken(user.getId(),user.getNickname());
// 登錄成功，返回到首頁顯示數據，將Token字符串傳過去，前端獲取即可使用
return "redirect:http://localhost:3000?token=" + jwtToken;
}catch (Exception e){
e.printStackTrace();
}
}
上面使用了一個HttpClientUtils工具來發送get請求，需要依賴commons-lang-2.6.jar、httpclient-4.3.2.jar、httpcore-4.3.1.jar、commons-io-2.4.jar這幾個Jar包。HttpClient發送請求的代碼，網上有很多，也可以自己封裝。本例所用的源碼如下：
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);
}
/**
* 發送一個 Post 請求, 使用指定的字符集編碼.
*
* @param url
* @param body RequestBody
* @param mimeType 例如 application/xml "application/x-www-form-urlencoded" a=1&b=2&c=3
* @param charset 編碼
* @param connTimeout 建立鏈接超時時間,毫秒.
* @param readTimeout 響應超時時間,毫秒.
* @return ResponseBody, 使用指定的字符集編碼.
* @throws ConnectTimeoutException 建立鏈接超時異常
* @throws SocketTimeoutException 響應超時
* @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);
}
// 設置參數
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")) {
// 執行 Https 請求.
client = createSSLInsecureClient();
res = client.execute(post);
} else {
// 執行 Http 請求.
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表單
*
* @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());
}
}
// 設置參數
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")) {
// 執行 Https 請求.
client = createSSLInsecureClient();
res = client.execute(post);
} else {
// 執行 Http 請求.
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();
}
}
}
/**
* 發送一個 GET 請求
*
* @param url
* @param charset
* @param connTimeout 建立鏈接超時時間,毫秒.
* @param readTimeout 響應超時時間,毫秒.
* @return
* @throws ConnectTimeoutException 建立鏈接超時
* @throws SocketTimeoutException 響應超時
* @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 {
// 設置參數
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")) {
// 執行 Https 請求.
client = createSSLInsecureClient();
res = client.execute(get);
} else {
// 執行 Http 請求.
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;
}
/**
* 從 response 裏獲取 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;
}
/**
* 創建 SSL連接
* @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<String,String> map = new HashMap<String,String>();
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();
}
}
}