SpingMvc-Day01

SpringMVC:
表述层作用：1.接受前端参数[SpringMVC简化]2.调用业务逻辑3.响应前端数据[SpringMVC简化]
SpringMVC组件：1.DispatcherServlet：处理全部请求2.handlerMapping：缓存handler方法和地址3.handlerAdapter：适配器、参数和相应简化4.ViewResovler视图解释器：查找视图页面、简化视图查找5.handler:处理器，
SpringMVC接收数据:1.访问路径设置@RequestMapping：将请求的URL地址和处理请求的方式关联起来，建立映射* 1.精准地址/user/log {"地址1","地址2"}* 2.支持模糊 * 任意一层字符串 | **任意层字符串*          /user/**          /user/*** 3.类上添加@RequestMapping也可以 类下面的方法公共的路径* 4.请求方式指定客户端 -> http(ger | post | put | delete) -> dispatcherServlet - > handler默认情况下:@RequestMapping("login)只要地址正确，任何请求方式都可以访问指定请求方式: @RequestMapping(value = "/login",method = RequestMethod.POST)@RequestMapping(value = "/register",method = {RequestMethod.GET,RequestMethod.POST})不符合的报405或者直接在方法上加@GetMapping @PostMapping @PutMapping @DeleteMapping2.接收参数[重点]①param和json的参数比较Param: key=value&key=valueJSON:  {key:value,key:value}②param参数接收1.直接接收/param/data?name=root&age=18//直接接收 参数=形参@RequestMapping("data")public String data(String name,int age){System.out.println("name = " + name + ", age = " + age);return "name = " + name + ", age = " + age;}    2.使用@RequestParam/param/data?account=root&age=18public String data1(@RequestParam(value = "account") String username , @RequestParam(required = false,defaultValue = "1") int page){@RequestParam:value：将account指定为usernamerequired = false 指定非必须传值defaultValue = "1" 设置默认值3.特殊场景接收①一值多收//一名多值 key=1&key=2 使用集合接收[但要使用@RequestParam]//param/data2?hbs=吃&hbs=玩&hbs=学习@GetMapping("data2")@ResponseBodypublic String data2(@RequestParam List<String> hbs){System.out.println("hbs = " + hbs);return "ok";②使用实体对象接值//用户注册（用户信息）  -》 对应的实体类 -》 插入到数据库、表//param/data3?name=二狗子&age=18// 准备一个对应属性的ger|set方法的实体类对象即可// 形参列表@RequestMapping("data3")@ResponseBodypublic String data3(User user){System.out.println("user = " + user);return user.toString();}}4.路径参数接收/user/root/123456//动态路径设置{key} = * {key}//接收路径参数@RequestMapping("{account}/{password}")public String login(@PathVariable(value = "account") String username,@PathVariable String password){System.out.println("username = " + username + ", password = " + password);return "username = " + username + ", password = " + password;}