设置了@RequestMapping("/jsp/info.do"),也可以写成"jsp/info.act"不影响
retuen "index";
suffix为".jsp"
访问/jsp/info.do
prefix为""时,会到web-inf下的jsp目录去找index.jsp
prefix为"test"时，会在web-inf下的jsp目录找testindex.jsp
prefix为"test/"时，会在web-inf下的jsp目录的test目录找index.jsp
prefix为"/"时,会到web-inf下找index.jsp
prefix为"/test/"时，会在web-inf下的test目录下找index.jsp