在spring mvc中实现在Controller中进行页面跳转有两种方式

在spring mvc中实现在Controller中进行页面跳转有两种方式
1.Java代码 

public ModelAndView login(HttpServletResponse response, String id) {   
response.sendRedirect("index.do="+id);   
return null;   
}  

public ModelAndView login(HttpServletResponse response, String id) {
response.sendRedirect("index.do="+id);
return null;
}

2.Java代码 

public ModelAndView login(HttpServletResponse response, String id) {   
  
return new ModelAndView("redirect:index.do="+id);   
}  

public ModelAndView login(HttpServletResponse response, String id) {

return new ModelAndView("redirect:index.do="+id);
}

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return new ModelAndView("redirect:" + downloadUrl);