java 写出企业微信登录的接口

对于企业微信登录的接口，可以使用Java语言编写以下代码：

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.alibaba.fastjson.JSONObject;

public class EnterpriseWeChatLoginServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    // 企业微信应用ID
    private static final String APP_ID = "企业微信应用ID";

    // 企业微信应用Secret
    private static final String APP_SECRET = "企业微信应用Secret";

    // 企业微信登录回调URL
    private static final String REDIRECT_URL = "企业微信登录回调URL";

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取企业微信授权登录的code
        String code = request.getParameter("code");

        // 获取access_token、openid
        String access_token_url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=" + APP_ID + "&corpsecret=" + APP_SECRET;
        String access_token_json = HttpUtil.get(access_token_url);
        String access_token = JSONObject.parseObject(access_token_json).getString("access_token");
        String openid_url = "https://qyapi.weixin.qq.com/cgi-bin/user/getuserinfo?access_token=" + access_token + "&code=" + code;
        String openid_json = HttpUtil.get(openid_url);
        String openid = JSONObject.parseObject(openid_json).getString("UserId");

        // 判断是否登录成功
        if (openid != null) {
            // 登录成功，跳转到指定页面
            response.sendRedirect(REDIRECT_URL);
        } else {
            // 登录失败，跳转到错误页面
            response.sendRedirect("错误页面URL");
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
}

需要注意的是，上述代码中的APP_ID、APP_SECRET和REDIRECT_URL需要替换为实际的值。此外，代码中使用了HttpUtil类来发送HTTP请求，需要自行实现该类的方法。