request.getRequestURL()和request.

request.getRequestURL() 返回全路径

request.getRequestURI() 返回除去host（域名或者ip）部分的路径

request.getContextPath() 返回工程名部分，如果工程映射为/，此处返回则为空

request.getServletPath() 返回除去host和工程名部分的路径

request.getRequestURL() http://localhost:8080/district_number/html/dataProcess.html

request.getRequestURI() /district_number/html/dataProcess.html

request.getContextPath()/district_number

request.getServletPath()html/dataProcess.html