Exception in thread “main“ org.jsoup.HttpStatusException: HTTP error fetching URL. Status=422, URL=

谁践踏了优雅 2022-11-30 01:36 19阅读 0赞

在使用JSoup模拟登录我校内网的时候报了如下错误：

Exception in thread "main" org.jsoup.HttpStatusException: HTTP error fetching URL. Status=422, URL=https://webvpn.ncepu.edu.cn/users/sign_in
    	at jsoup@1.10.2/org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:679)
    	at jsoup@1.10.2/org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:628)
    	at jsoup@1.10.2/org.jsoup.helper.HttpConnection.execute(HttpConnection.java:260)
    	at EDM.login_final.main(login_final.java:66)

错误原因：模拟登录需要提交表单数据（浏览器按F12可查看）：

utf8: ✓
    authenticity_token: DNLRC2amJXtJtAypVp+4O9igPVAd+743zAK9AJbkTXWiojT0612nc5bDJjQjdX0au/YWR7xnbOwtULk4O5ACpg==
    user[login]: ************
    user[password]: ******
    user[dymatice_code]: unknown
    commit: 登录 Login

刚开始我是直接手动给connect对象添加数据，总是报422错误。调试了一段时间后发现：表单数据中的authenticity\_token竟然是动态变化的…。于是这种做法就是错误的：

connect.data("user[login]", "************").data("user[password]", "******");
    connect.data("dymatice_code", "unknown").data("utf8", "?").data("commit", "登录 Login");
    connect.data("authenticity_token", "dbZNX3RljHFODgsb3tqZszd/jHjOrQYvnfhwWrPzTCU39NfVO9UcG5/rT3aKgxYu7xfCudoq4ibcDfn0rCZG0A==");

解决办法：动态请求网页数据来获得form data：

Connection con = Jsoup.connect(LOGIN_URL); 
    con.header(USER_AGENT, USER_AGENT_VALUE); 
    Response res = con.execute();
    Document d = Jsoup.parse(res.body());       // 通过Jsoup将返回信息转换为Dom树
    List<Element> elements = d.select("form");  // 获取提交form表单，可以通过查看页面源码代码得知
    Map<String, String> datas = new HashMap<>();
    for (Element e : elements.get(0).getAllElements()) { 
        if (e.attr("name").equals("user[login]")) { 
            e.attr("value", ************);
        }
        if (e.attr("name").equals("user[password]")) { 
            e.attr("value", ******);
        }
         //添加其它信息
        if (e.attr("name").length() > 0) { 
            datas.put(e.attr("name"), e.attr("value"));
        }
    }