第二步：创建一个应用并填写信息
在这里插入图片描述
第四步：在前台准备一个按钮用于GitHub账号登陆： <a rel="external nofollow" href="https://github.com/login/oauth/authorize?client_id=对应自己申请的client id&state=STATE&redirect_uri=http://localhost/callback;">github登录</a>
注意：redirect_uri是回调地址，必须和在注册应用时候填写的回调地址一致。
第五步：准备java代码，这步中的部分方法和常量依赖于后面的：【常量类】、【自定义工具类】 package cn.itsource.crm.web.controller;import cn.itsource.crm.domain.Github;import cn.itsource.crm.service.IGithubService;import cn.itsource.util.GitHubConstant;import cn.itsource.util.HttpClientUtils;import org.apache.commons.lang3.StringUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.http.HttpServletRequest;import java.util.Map;/** * @Created with IDEA * @author: Super Zheng * @Description: 第三方登陆GitHub * @Date:2018/12/26 * @Time:18:59 */@Controllerpublic class GithubLoginController { @Autowired private IGithubService githubService;//回调地址 @RequestMapping("/callback") public String callback(String code, String state, Model model, HttpServletRequest req) throws Exception{ if(!StringUtils.isEmpty(code)&&!StringUtils.isEmpty(state)){ //拿到我们的code,去请求token //发送一个请求到 String token_url = GitHubConstant.TOKEN_URL.replace("CODE", code); //得到的responseStr是一个字符串需要将它解析放到map中 String responseStr = HttpClientUtils.doGet(token_url); // 调用方法从map中获得返回的--》 令牌 String token = HttpClientUtils.getMap(responseStr).get("access_token"); //根据token发送请求获取登录人的信息 ，通过令牌去获得用户信息 String userinfo_url = GitHubConstant.USER_INFO_URL.replace("TOKEN", token); responseStr = HttpClientUtils.doGet(userinfo_url);//json Map<String, String> responseMap = HttpClientUtils.getMapByJson(responseStr); // 成功则登陆 return "/main"; } // 否则返回到登陆页面 return "/login/login"; }} 代码中的常量字段： package cn.itsource.util;/** * @Created with IDEA * @author: Super Zheng * @Description: java类作用描述 * @Date:2018/12/26 * @Time:12:20 */public class GitHubConstant { // 这里填写在GitHub上注册应用时候获得 CLIENT ID public static final String CLIENT_ID="a7dc7e3d";//这里填写在GitHub上注册应用时候获得 CLIENT_SECRET public static final String CLIENT_SECRET="1faa46333a4d1c904"; // 回调路径 public static final String CALLBACK = "http://localhost/callback"; //获取code的url public static final String CODE_URL = "https://github.com/login/oauth/authorize?client_id="+CLIENT_ID+"&state=STATE&redirect_uri="+CALLBACK+""; //获取token的url public static final String TOKEN_URL = "https://github.com/login/oauth/access_token?client_id="+CLIENT_ID+"&client_secret="+CLIENT_SECRET+"&code=CODE&redirect_uri="+CALLBACK+""; //获取用户信息的url public static final String USER_INFO_URL = "https://api.github.com/user?access_token=TOKEN";} 第三方登陆工具类中用到的依赖包： <dependencies> <!--java代码发送请求依赖包--> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.6</version> </dependency> <!--将json转换成map--> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.47</version> </dependency> </dependencies> 第三方登陆工具类： package cn.itsource.util;import com.alibaba.fastjson.JSONObject;import org.apache.http.HttpEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.util.EntityUtils;import java.util.HashMap;import java.util.Map;/** * @Created with IDEA * @author: Super Zheng * @Description: java类作用描述 * @Date:2018/12/26 * @Time:12:58 */public class HttpClientUtils { /** * 发送get请求，利用java代码发送请求 * @param url * @return * @throws Exception */ public static String doGet(String url) throws Exception{ CloseableHttpClient httpclient = HttpClients.createDefault(); HttpGet httpGet = new HttpGet(url); // 发送了一个http请求 CloseableHttpResponse response = httpclient.execute(httpGet); // 如果响应200成功,解析响应结果 if(response.getStatusLine().getStatusCode()==200){ // 获取响应的内容 HttpEntity responseEntity = response.getEntity(); return EntityUtils.toString(responseEntity); } return null; } /** * 将字符串转换成map * @param responseEntity * @return */ public static Map<String,String> getMap(String responseEntity) { Map<String, String> map = new HashMap<>(); // 以&来解析字符串 String[] result = responseEntity.split("\&"); for (String str : result) { // 以=来解析字符串 String[] split = str.split("="); // 将字符串存入map中 if (split.length == 1) { map.put(split[0], null); } else { map.put(split[0], split[1]); } } return map; } /** * 通过json获得map * @param responseEntity * @return */ public static Map<String,String> getMapByJson(String responseEntity) { Map<String, String> map = new HashMap<>(); // 阿里巴巴fastjson 将json转换成map JSONObject jsonObject = JSONObject.parseObject(responseEntity); for (Map.Entry<String, Object> entry : jsonObject.entrySet()) { String key = entry.getKey(); // 将obj转换成string String value = String.valueOf(entry.getValue()) ; map.put(key, value); } return map; }} 第六步：测试-
总结：整体原理分析：