/**
 * 向页面回传数据显示 handle01/02/03
 * 使用 model map modelMap 回传数据 放置在request中
 */
@RequestMapping("/handle01")
public String handler01(Map<String, String> map) {
    map.put("msg","你好1！");
    return "success";
}

@RequestMapping("/handle02")
public String handler02(Model model) {
    model.addAttribute("msg","你好2");
    return "success";
}

@RequestMapping("/handle03")
public String handler03(ModelMap modelMap) {
    modelMap.addAttribute("msg","你好3");
    return "success";
}

/**
 * modelAndView 携带数据
 */

@RequestMapping("/handle04")
public ModelAndView handler(){
    ModelAndView mv = new ModelAndView("success");
    mv.addObject("msg","你好04");
    return mv;
}

// 先于目标方法执行，获取了数据库中的斗个对象的信息
@ModelAttribute
public void hahaMyModelAttribute(Map<String, Object> map){
        
Book book = new Book(100, "西游记", "吴承恩", 98, 10, 98.98);
    System.out.println("数据库中查到的图书信息是："+book);
    map.put("haha", book);
    b1 = book;
    o1 = map;
    System.out.println("modelAttribute方法...查询了图书并给你保存起来了...他用的map的类             型："+map.getClass());
    }
}

// 目标方法，在目标方法中使用查询到的对象
@RequestMapping("/updateBook")
public String updateBook(@ModelAttribute("haha")Book book,Map<String, Object> model){
    o2 = model;
    b2  = book;
    Object haha = model.get("haha");
    //System.out.println("传入的model："+model.getClass());
    System.out.println("o1==o2?"+(o1 == o2));
    System.out.println("b1==b2?"+(b1 == b2)+"-->"+(b2 == haha));
     System.out.println("页面要提交过来的图书信息："+book);
    return "success";
    }