servlet: Adapt web.xml to standard so that tomcat can run it

servlet/src/main/webapp/WEB-INF/web.xml

@@ -1,44 +1,62 @@
-<web-app>
+<web-app version="3.0"
+         xmlns="http://java.sun.com/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
+    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
   <servlet>
     <servlet-name>json</servlet-name>
     <servlet-class>hello.JsonServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/json$' servlet-name='json'/>
+  <servlet-mapping>
+      <servlet-name>json</servlet-name>
+      <url-pattern>/json</url-pattern>
+  </servlet-mapping>
   <servlet>
     <servlet-name>plaintext</servlet-name>
     <servlet-class>hello.PlaintextServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/plaintext$' servlet-name='plaintext'/>
+    <servlet-mapping>
+        <servlet-name>plaintext</servlet-name>
+        <url-pattern>/plaintext</url-pattern>
+    </servlet-mapping>
   <servlet>
     <servlet-name>db</servlet-name>
     <servlet-class>hello.DbPoolServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/db$' servlet-name='db'/>
+    <servlet-mapping>
+        <servlet-name>db</servlet-name>
+        <url-pattern>/db</url-pattern>
+    </servlet-mapping>
   <servlet>
     <servlet-name>fortunes</servlet-name>
     <servlet-class>hello.FortunesServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/fortunes$' servlet-name='fortunes'/>
+    <servlet-mapping>
+        <servlet-name>fortunes</servlet-name>
+        <url-pattern>/fortunes</url-pattern>
+    </servlet-mapping>
   <servlet>
     <servlet-name>update</servlet-name>
     <servlet-class>hello.UpdateServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/update$' servlet-name='update'/>
+    <servlet-mapping>
+        <servlet-name>update</servlet-name>
+        <url-pattern>/update</url-pattern>
+    </servlet-mapping>
   <servlet>
     <servlet-name>postgres</servlet-name>
     <servlet-class>hello.PostgresServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/postgres$' servlet-name='postgres'/>
+    <servlet-mapping>
+        <servlet-name>postgres</servlet-name>
+        <url-pattern>/postgres</url-pattern>
+    </servlet-mapping>
   <servlet>
     <servlet-name>postgres-update</servlet-name>
     <servlet-class>hello.PostgresUpdateServlet</servlet-class>
-    <load-on-startup/>
   </servlet>
-  <servlet-mapping url-regexp='^/postgres-update$' servlet-name='postgres-update'/>
+    <servlet-mapping>
+        <servlet-name>postgres-update</servlet-name>
+        <url-pattern>/postgres-update</url-pattern>
+    </servlet-mapping>
 </web-app>