アクセスされたURLに関するパス情報を取得
　String requestUri       = request.getRequestURI(); /TestWeb/urltest/aaa
　String requestUrl       = request.getRequestURL().toString(); http://localhost:8080/TestWeb/urltest/aaa

---

　String pathInfo          = request.getPathInfo(); /aaa
　String queryString     = request.getQueryString(); bbb=ccc
　String pathTranslated = request.getPathTranslated(); C:\(中略)\TestWeb\aaa
　String schema           = request.getScheme(); http
　String serverName     = request.getServerName(); localhost
　int serverPort            = request.getServerPort(); 8080
　String servletPath      = request.getServletPath(); /urltest
　String contextPath     = request.getContextPath(); /TestWeb

---

　http://localhost:8080/TestWeb/urltest/aaa?bbb=ccc
　[schema]://[serverName]:[serverPort][contextPath][servletPath][pathInfo]?[queryString]