Spring-mvc 响应，回写数据的9中方式

Spring-mvc 响应，回写数据的10中方式

@Controller("userController")
@RequestMapping("/user")
public class UserController {

    @RequestMapping(value = "/test")
    public String save(){
        System.out.println("Controller save running......");
        return "redirect:/index.jsp";
//        代表从当前web应用下找这个资源
    }

    @RequestMapping("test2")
    public ModelAndView save2(){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("username","哈哈");
        modelAndView.setViewName("/index.jsp");
        return modelAndView;
    }
    直接new一个ModelAndView

    @RequestMapping("test3")
    public ModelAndView save3(ModelAndView modelAndView){

        modelAndView.addObject("username","程");
        modelAndView.setViewName("/index.jsp");
        return modelAndView;
    }
	Spring帮你注入modelAndView

    @RequestMapping("test4")
    public String save4(Model model){
        int a = 1;
        model.addAttribute("username","王");
        return "/index.jsp";
    }
    直接用model，使用addAttribute方法

    @RequestMapping("test5")
    public String save5(HttpServletRequest request){
        request.setAttribute("username","哈哈");
        return "/index.jsp";
    }
    使用request

    @RequestMapping("/test6")
    public void save6(HttpServletResponse response) throws IOException {
        response.getWriter().println("<h1>hello</h1>");
    }
    使用response直接输出在浏览器上

    @RequestMapping("/test7")
    @ResponseBody
    public String save7(){
        return "hello.jsp";
    }
    

    @RequestMapping("/test8")
    @ResponseBody
    public String save8(){
        return "index";
    }
    再web.xml中配置

    @RequestMapping("/test9")
    @ResponseBody
    public String save9(){
        User user = new User();
        user.setAge(14);
        user.setName("lili");
        String s = JSON.toJSONString(user);
        return s;
    }

    @RequestMapping("/test10")
    @ResponseBody
//    expect to convert User to JSON
    public User save10(){
        User user = new User();
        user.setAge(14);
        user.setName("lili");
//        direct
        return user;
    }

controller: 对servlet类进行Bean的申明

Request("/user"):url找到该类的地址，相当于再r
ul后再添加"/user"