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】
演示地址: http://cncounter.duapp.com/druid/index.html
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