JAVA实现微信授权登录

阳光穿透心脏的1/2处 2021-06-26 16:06 656阅读 0赞

1.先写一个工具类 AuthUtil.java 来存放APPID等信息

public class AuthUtil {
    	public static final String APPID = "换成自己的APPID ";
    	public static final String APPSECRET = "换成自己的APPSECRET ";
    
    	public static JSONObject doGetJson(String url) throws ClientProtocolException, IOException {
    		JSONObject jsonObject = null;
    		DefaultHttpClient client = new DefaultHttpClient();
    		HttpGet httpGet = new HttpGet(url);
    		HttpResponse response = client.execute(httpGet);
    		HttpEntity entity = response.getEntity();
    		if (entity != null) {
    			String result = EntityUtils.toString(entity, "UTF-8");
    			jsonObject = JSONObject.fromObject(result);
    		}
    		httpGet.releaseConnection();
    		return jsonObject;
    	}
    }

2.新建一个 LoginController.java 类来实现授权登录

import java.io.IOException;
    import java.net.URLEncoder;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.apache.http.client.ClientProtocolException;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    import net.sf.json.JSONObject;
    
    @Controller
    public class LoginController extends HttpServlet {
    
    	/**
    	 * 微信授权登录
    	 */
    	@RequestMapping("/wxLogin")
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
    		// backUrl 需要遵循微信官方的定义，微信的接口只能用 https 来访问
    		// 所以我这里是直接把整个项目打包成 jar 包，然后扔到自己的服务器上
    		String backUrl = "https://www.yyzheng.cn/o2o/callBack";
    		String url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid=" + AuthUtil.APPID + "&redirect_uri="
    				+ URLEncoder.encode(backUrl) + "&response_type=code" + "&scope=snsapi_userinfo"
    				+ "&state=STATE#wechat_redirect";
    		response.sendRedirect(url);
    	}
    
    	/**
    	 * 登录成功的回调函数
    	 * 
    	 * @param request
    	 * @param response
    	 * @throws ClientProtocolException
    	 * @throws IOException
    	 * @throws ServletException
    	 */
    	@RequestMapping("/callBack")
    	protected void deGet(HttpServletRequest request, HttpServletResponse response)
    			throws ClientProtocolException, IOException, ServletException {
    		String code = request.getParameter("code");
    		String url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=" + AuthUtil.APPID + "&secret="
    				+ AuthUtil.APPSECRET + "&code=" + code + "&grant_type=authorization_code";
    		JSONObject jsonObject = AuthUtil.doGetJson(url);
    		String openid = jsonObject.getString("openid");
    		String token = jsonObject.getString("access_token");
    		String infoUrl = "https://api.weixin.qq.com/sns/userinfo?access_token=" + token + "&openid=" + openid
    				+ "&lang=zh_CN";
    		JSONObject userInfo = AuthUtil.doGetJson(infoUrl);
    		
    		if( userInfo != null ){
    			// 这里是把授权成功后，获取到的东西放到 info 里面，前端可以通过 EL 表达式直接获取相关信息
    			request.setAttribute("info", userInfo);
    			// 这里是授权成功返回的页面
    			request.getRequestDispatcher("/success.jsp").forward(request, response);
    		}else{
    			request.getRequestDispatcher("/fail.jsp").forward(request, response);
    		}
    		
    	}
    }

3.写一个页面来访问授权功能

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1">
    <title>Insert title here</title>
    </head>
    <body>
    	<a href="/o2o/wxLogin">微信公众授权登录</a>
    </body>
    </html>

4.微信授权成功访问的页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1">
    <title>Insert title here</title>
    </head>
    <body>
    授权成功！！！
    ${info }
    </body>
    </html>

5.微信授权失败访问的页面