Spring Boot + 微信公众号授权登录获取用户信息

通过微信公众平台的官方文档，总结出网页授权流程分为：

1、引导用户进入授权页面同意授权，获取code

2、通过code换取网页授权access_token（与基础支持中的access_token不同）

3、通过网页授权access_token和openid获取用户基本信息（支持UnionID机制）

简单总结成代码就是：
     1、controller

@RestController
@RequestMapping("/wxAuth")
public class WxLoginController {
 
    @RequestMapping("/login")
    public void wxLogin(HttpServletResponse response) throws IOException {
        //请求获取code的回调地址
        //用线上环境的域名或者用内网穿透，不能用ip
        String callBack = "http://你的域名/wxAuth/callBack";
 
        //请求地址
        String url = "https://open.weixin.qq.com/connect/oauth2/authorize" +
                "?appid=" + 你的appid +
                "&redirect_uri=" + URLEncoder.encode(callBack) +
                "&response_type=code" +
                "&scope=snsapi_userinfo" +
                "&state=STATE#wechat_redirect";
        //重定向
        response.sendRedirect(url);
    }
    
    //	回调方法
    @RequestMapping("/callBack")
    public void wxCallBack(HttpServletRequest request,HttpServletResponse response) throws IOException {
        String code = request.getParameter("code");
 
        //获取access_token
        String url = "https://api.weixin.qq.com/sns/oauth2/access_token" +
                "?appid=" + appId +
                "&secret=" + appSecret +
                "&code=" + code +
                "&grant_type=authorization_code";
 
        String result = HttpClientUtil.doGet(url);
 
        System.out.println("请求获取access_token:" + result);
		//返回结果的json对象
        JSONObject resultObject = JSON.parseObject(result);
 
		//请求获取userInfo
        String infoUrl = "https://api.weixin.qq.com/sns/userinfo" +
                "?access_token=" + resultObject.getString("access_token") +
                "&openid=" + resultObject.getString("openid") +
                "&lang=zh_CN";
 
        String resultInfo = HttpClientUtil.doGet(infoUrl);
 
		//此时已获取到userInfo，再根据业务进行处理
        System.out.println("请求获取userInfo:" + resultInfo);
 
    }
}

二、用到的HttpClientUtil

public class HttpClientUtil {
 
	public static String doGet(String url, Map<String, String> param) {
 
		// 创建Httpclient对象
		CloseableHttpClient httpclient = HttpClients.createDefault();
 
		String resultString = "";
		CloseableHttpResponse response = null;
		try {
			// 创建uri
			URIBuilder builder = new URIBuilder(url);
			if (param != null) {
				for (String key : param.keySet()) {
					builder.addParameter(key, param.get(key));
				}
			}
			URI uri = builder.build();
 
			// 创建http GET请求
			HttpGet httpGet = new HttpGet(uri);
 
			// 执行请求
			response = httpclient.execute(httpGet);
			// 判断返回状态是否为200
			if (response.getStatusLine().getStatusCode() == 200) {
				resultString = EntityUtils.toString(response.getEntity(), "UTF-8");
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (response != null) {
					response.close();
				}
				httpclient.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return resultString;
	}
 
	public static String doGet(String url) {
		return doGet(url, null);
	}
 
	public static String doPost(String url, Map<String, String> param) {
		// 创建Httpclient对象
		CloseableHttpClient httpClient = HttpClients.createDefault();
		CloseableHttpResponse response = null;
		String resultString = "";
		try {
			// 创建Http Post请求
			HttpPost httpPost = new HttpPost(url);
			// 创建参数列表
			if (param != null) {
				List<NameValuePair> paramList = new ArrayList<>();
				for (String key : param.keySet()) {
					paramList.add(new BasicNameValuePair(key, param.get(key)));
				}
				// 模拟表单
				UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList);
				httpPost.setEntity(entity);
			}
			// 执行http请求
			response = httpClient.execute(httpPost);
			resultString = EntityUtils.toString(response.getEntity(), "utf-8");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				response.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
 
		return resultString;
	}
	
	public static String doPost(String url) {
		return doPost(url, null);
	}
	
	public static String doPostJson(String url, String json) {
		// 创建Httpclient对象
		CloseableHttpClient httpClient = HttpClients.createDefault();
		CloseableHttpResponse response = null;
		String resultString = "";
		try {
			// 创建Http Post请求
			HttpPost httpPost = new HttpPost(url);
			// 创建请求内容
			StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
			httpPost.setEntity(entity);
			// 执行http请求
			response = httpClient.execute(httpPost);
			resultString = EntityUtils.toString(response.getEntity(), "utf-8");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				response.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
 
		return resultString;
	}
}

3 pom.xml'

<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>1.2.7</version>
		</dependency>
 
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpclient</artifactId>
			<version>4.3.5</version>
		</dependency>