URI、URL、URN的关系

• URI：Uniform Resource Identifier，统一资源标识符，例如request.getRequestURI()【/fas/user/registerVue】
• URL：Uniform Resource Locator，统一资源定位符，例如request.getRequestURL()【http://localhost:8888/fas/user/registerVue】
• URN：Uniform Resource Name，统一资源名

关系
request.getRequestURL() = ip:port + (request.getRequestURI() = request.getContextPath() + request.getServletPath())
如：
request.getRequestURI() = /fas/user/registerVue
request.getRequestURL() = http://localhost:8888/fas/user/registerVue
request.getContextPath() = /fas
request.getServletPath() = /user/registerVue