为Druid监控配置访问权限(配置访问监控信息的用户与密码)

Druid是一个强大的新兴数据库连接池,兼容DBCP，是阿里巴巴做的开源项目.

不仅提供了强悍的数据源实现,还内置了一个比较靠谱的监控组件。 

GitHub项目主页: https://github.com/alibaba/druid

QQ群:  点击链接加入群【阿里开源技术交流】

常见问题回答请参考: https://github.com/alibaba/druid/wiki/%E5%B8%B8%E8%A7%81%E9%97%AE%E9%A2%98

一篇CSDN对Druid的介绍  druid简单教程

因为想要监控数据,又不愿意谁都可以访问,所以想要配置个密码.在开源群里一问,就知道原来内部已经有实现了.

先贴完成后的代码:

web.xml 部分:

	<!-- Druid,监控数据库,以及WEB访问连接信息 -->
	<!-- 参考: https://github.com/alibaba/druid/wiki/%E9%85%8D%E7%BD%AE_%E9%85%8D%E7%BD%AEWebStatFilter -->
	<filter>
		<filter-name>DruidWebStatFilter</filter-name>
		<filter-class>com.alibaba.druid.support.http.WebStatFilter</filter-class>
		<init-param>
			<param-name>exclusions</param-name>
			<param-value>*.js,*.gif,*.jpg,*.png,*.css,*.ico,*.jsp,/druid/*,/download/*</param-value>
		</init-param>
		<init-param>
			<param-name>sessionStatMaxCount</param-name>
			<param-value>2000</param-value>
		</init-param>
		<init-param>
	        <param-name>sessionStatEnable</param-name>
	        <param-value>true</param-value>
	    </init-param>
		<init-param>
	        <param-name>principalSessionName</param-name>
	        <param-value>session_user_key</param-value>
	    </init-param>
	    <init-param>
		    <param-name>profileEnable</param-name>
		    <param-value>true</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>DruidWebStatFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	<!-- 配置 Druid 监控信息显示页面 -->
	<servlet>
		<servlet-name>DruidStatView</servlet-name>
		<servlet-class>com.alibaba.druid.support.http.StatViewServlet</servlet-class>
		<init-param>
			<!-- 允许清空统计数据 -->
			<param-name>resetEnable</param-name>
			<param-value>true</param-value>
		</init-param>
		<init-param>
			<!-- 用户名 -->
			<param-name>loginUsername</param-name>
			<param-value>druid</param-value>
		</init-param>
		<init-param>
			<!-- 密码 -->
			<param-name>loginPassword</param-name>
			<param-value>druid</param-value>
		</init-param>
	</servlet>
	<servlet-mapping>
		<servlet-name>DruidStatView</servlet-name>
		<url-pattern>/druid/*</url-pattern>
	</servlet-mapping>

下面分享一下如何查找的。

首先,因为使用的是 MAVEN, 所以查看源码时maven会自动帮你下载. 我们在 web.xml 中点击 com.alibaba.druid.support.http.StatViewServlet 进入class文件,等一会源码下载好就可以查看. 发现有类似下面这样的代码: 

public class StatViewServlet extends ResourceSerlvet {

    private final static Log      LOG                     = LogFactory.getLog(StatViewServlet.class);

    private static final long     serialVersionUID        = 1L;

    public static final String    PARAM_NAME_RESET_ENABLE = "resetEnable";

    public static final String    PARAM_NAME_JMX_URL      = "jmxUrl";
    public static final String    PARAM_NAME_JMX_USERNAME = "jmxUsername";
    public static final String    PARAM_NAME_JMX_PASSWORD = "jmxPassword";

    private DruidStatService      statService             = DruidStatService.getInstance();

    /** web.xml中配置的jmx的连接地址 */
    private String                jmxUrl                  = null;
    /** web.xml中配置的jmx的用户名 */
    private String                jmxUsername             = null;
    /** web.xml中配置的jmx的密码 */
    private String                jmxPassword             = null;
.........

可以看出,继承了 StatViewServlet extends ResourceSerlvet

而在其中的 jmxUrl、jmxUsername 和 jmxPassword 很显然是连接远程 JMX时使用的,那么我就想着去看看父类: com.alibaba.druid.support.http.ResourceSerlvet

@SuppressWarnings("serial")
public abstract class ResourceSerlvet extends HttpServlet {

    private final static Log   LOG                 = LogFactory.getLog(ResourceSerlvet.class);

    public static final String SESSION_USER_KEY    = "druid-user";
    public static final String PARAM_NAME_USERNAME = "loginUsername";
    public static final String PARAM_NAME_PASSWORD = "loginPassword";
    public static final String PARAM_NAME_ALLOW    = "allow";
    public static final String PARAM_NAME_DENY     = "deny";
    public static final String PARAM_REMOTE_ADDR   = "remoteAddress";

    protected String           username            = null;
    protected String           password            = null;
..........

看到了 username 和 password,很高兴,先配置了试试,但是配置这两个初始化参数后没起作用,于是继续查找. 看到了 service方法,我们知道,Servlet的业务逻辑就是从这里开始的。

    public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        ......
        if (isRequireAuth() //
            && !ContainsUser(request)//
            && !("/login.html".equals(path) //
                 || path.startsWith("/css")//
                 || path.startsWith("/js") //
            || path.startsWith("/img"))) {
            if (contextPath == null || contextPath.equals("") || contextPath.equals("/")) {
                response.sendRedirect("/druid/login.html");
            } else {
                if ("".equals(path)) {
                    response.sendRedirect("druid/login.html");
                } else {
                    response.sendRedirect("login.html");
                }
            }
            return;
        }
    ......

发现调用了   isRequireAuth() 方法,看着像是判断是否需要授权验证,于是进去看

    public boolean isRequireAuth() {
        return this.username != null;
    }

那现在知道是 username 在作怪,也设置了,但是没有起作用,于是搜索 username ,

    public void init() throws ServletException {
        initAuthEnv();
    }

    private void initAuthEnv() {
        String paramUserName = getInitParameter(PARAM_NAME_USERNAME);
        if (!StringUtils.isEmpty(paramUserName)) {
            this.username = paramUserName;
        }

        String paramPassword = getInitParameter(PARAM_NAME_PASSWORD);
        if (!StringUtils.isEmpty(paramPassword)) {
            this.password = paramPassword;
        }
      ......

然后发现了初始化验证环境时使用了PARAM_NAME_USERNAME这个参数,顺便的学习了一个新API: getInitParameter 方法获取 Servlet的初始化参数, 是HttpServlet的父类 GenericServlet 类提供的:

String paramUserName = getInitParameter(PARAM_NAME_USERNAME);

那么很简单,找到 PARAM_NAME_USERNAME 即可:

    public static final String PARAM_NAME_USERNAME = "loginUsername";
    public static final String PARAM_NAME_PASSWORD = "loginPassword";

于是在 web.xml 中换上,OK，成功进行了拦截.
你也可以参考这里:   CNCounter项目的web.xml