Spring MVC中如何使用forward进行请求转发呢？

Spring MVC种forward请求是一种服务器端请求方式，它无需通过客户端，可以提高系统的转发速度，
同时转发的时候，会借助HttpServletRequest转发请求信息，他们转发的是同一个request对象

ViewResolver请求转发

@RequestMapping(value="/testredirect",method = { RequestMethod.POST, RequestMethod.GET })  
public  String testredirect(HttpServletResponse response){  
    return "forward:/index";  
}

带参数

@RequestMapping(value="/testredirect",method = { RequestMethod.POST, RequestMethod.GET })  
public  String testredirect(HttpServletRequest request){ 
    request.setAttribute("username", "51gjie");   //把username参数传递到request中
    return "forward:/user/index";  
}

ModelAndView请求转发

@RequestMapping(value="/restredirect",method = { RequestMethod.POST, RequestMethod.GET })  
public  ModelAndView restredirect(String userName){  
    ModelAndView  model = new ModelAndView("forward:/main/index");//默认forward，可以不用写
    return model;  
}

@RequestMapping(value="/toredirect",method = { RequestMethod.POST, RequestMethod.GET })  
public  ModelAndView toredirect(String userName){  
    ModelAndView  model = new ModelAndView("/user/userinfo");   
    model.addObject("userName", userName);  //把userName参数带入到controller的RedirectAttributes
    return model;  
}