Druid如何跳过登录

即直接进入/druid/index.html

1.错误做法

很多都是这样配置的，可是并不能跳过登录 
@WebServlet(urlPatterns = "/druid/*",
        initParams={
                @WebInitParam(name="allow",value="127.0.0.1"),// IP白名单 (没有配置或者为空，则允许所有访问)
                @WebInitParam(name="deny",value=""),// IP黑名单 (存在共同时，deny优先于allow)
                @WebInitParam(name="loginUsername",value="root"),// 用户名
                @WebInitParam(name="loginPassword",value="root"),// 密码
                @WebInitParam(name="resetEnable",value="false")// 禁用HTML页面上的“Reset All”功能
        })
public class DruidStatViewServlet extends StatViewServlet {
}

Application.java 

@ServletComponentScan

2.正确做法

druid自带的登录时的ajax请求源码 
      $.namespace("druid.login");
       druid.login = function () {  
           return  {
              login : function() {
                  $.ajax({
                    type: 'POST',
                    url: "submitLogin",
                    data: $("#loginForm").serialize(),
                    success: function(data) {
                      if("success" == data)
                          location.href = "index.html";
                      else {
                          $("#alertInfo").show();
                          $("#loginForm")[0].reset();
                      }
                    },
                    dataType: "text"
                  });
              }
           }
      }();

      $(document).ready(function() {
          $("#loginBtn").click(druid.login.login);
     });

通过源码可以发现 ajax 提交到 submitLogin,返回值是 success 就是登录成功

一般都是用于菜单栏（注意*）

1.通常，当我们点击菜单的某一项时，发出请求，请求的是/druid/login.html

2.现在我们需要将菜单点击后发出一个新的请求，例如：/toDruidLogin

3.在IndexController里面拦截请求 /toDruidLogin

code：

@RequestMapping("/toDruidLogin")
public String toDruidLogin(HttpSession session){
    if (session.getAttribute("user")!=null){
        return "druidlogin";
    }
    return "redirect:/login";
}

4.新建对应页面，例如druidlogin.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <link rel="stylesheet" th:href="@{/layui/css/layui.css}">
</head>
<body>
<!--jquery.min-->
<script th:src="@{https://code.jquery.com/jquery-3.4.1.min.js}" type="text/javascript"></script>
<script th:src="@{/layui/layui.js}" charset="utf-8"></script>
<script>
    layui.use(['layer','element'], function() {
        $(function () {
            autoLogin();
        })

        /** 自动登录 @author gaoyuan */
        function autoLogin() {
            var loadingLayer = layer.load(1, {shade: [0.1, '#fff']});//loading
            $.ajax({
                type: 'get',
                url: '/doDruidLogin',
                dataType: "text",
                data: {},
                success: function (data) {
                    layer.close(loadingLayer);
                    if (data == "success") {
                        location.href = "/druid";
                    } else {
                        layer.msg('自动登录出错，请手动登录！', {icon: 2}, function () {
                            location.href = "/druid";
                        });
                    }
                }, error: function () {
                    layer.close(loadingLayer);
                }
            });
        }
    });

</script>
</body>
</html>

5.模拟druid的自带的ajax请求，请求 /doDruidLogin

全部代码如上 

$.ajax({
    type: 'get',
    url: '/doDruidLogin',
    dataType: "text",
    data: {},
    success: function (data) {
        if (data == "success") {
            location.href = "/druid";
        }
    }
});

6.在IndexController里面拦截请求 /doDruidLogin

此处随意写，过滤后不会执行，但必须要拦截/doDruidLogin，否则会保错

@RequestMapping("/doDruidLogin")
public String doDruidLogin(HttpSession session){
    if (session.getAttribute("user")!=null){
        return "/"; 
    }
    return "redirect:/login";
}

7.最重要一点Filter

@Configuration
@WebFilter(filterName = "moni",urlPatterns = "/doDruidLogin")
public class DruidLoginFilter implements Filter {
    private static final Logger log = LoggerFactory.getLogger(DruidLoginFilter.class);
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("DruidLoginFilter初始化");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = ((HttpServletResponse) servletResponse);
        String requestUrl = request.getRequestURL().toString();
        //log.info(requestUrl);
        // 针对druid做自动登录
        if(requestUrl.contains("/doDruidLogin")){
            String queryString = "loginUsername=root&loginPassword=root";
            // 获取完整路径
          //  log.info("====="+requestUrl);
            StringBuffer url = new StringBuffer(requestUrl);
            // 获取路径加上项目名称
            String tempContextUrl = url.delete(url.length() - request.getRequestURI().length(), url.length()).append(request.getServletContext().getContextPath()).append("/").toString();
          //  log.info(tempContextUrl);
            /** 构造新地址，其实就是druid的登录地址 */
            URL newUrl = new URL(tempContextUrl + "druid/submitLogin?" + queryString);
           // log.info(newUrl.toString());
            response.setStatus(307);
            response.setHeader("Location", newUrl.toString());
            response.setHeader("Connection", "close");
            //允许所有跨域请求
            response.addHeader("Access-Control-Allow-Origin", "*");
        }else {
            chain.doFilter(request,response);
        }

    }

    @Override
    public void destroy() {
        log.info("DruidLoginFilter销毁");
    }
}

doFilter里面判断请求链接是否包含 /doDruidLogin

  if(requestUrl.contains("/doDruidLogin")){
        //将参数拼接到 一个Url
        //状态码307 要求浏览器继续向 Location 的地址 POST 内容。
         response.setStatus(307);
        response.setHeader("Location", newUrl.toString());
        response.setHeader("Connection", "close");
        //所以会跳转到 /druid/index.html
  }else{
    //放行...
    chain.doFilter(request,response);
  }

3.最后GIF展示

此篇完！