Springmvc 注解学习

SpringMVC注解详情

• 路劲数组访问，多路径访问一个controller

  • @RequestMapping(value=["/uri","/uri2"])
  • @RequestMapping(path=["/uri","/uri2"])

• 限定请求方式只能为GET(其他方式同理,可以写成数组）:

  @RequestMapping(method=RequestMethod.GET)

  @RequestMapping(path ={"p1","p2"},method= RequestMethod.GET)
      public String onlyget(){
          System.out.println("this is onlygetMethod");
          return "test";
      }
  

获取项目的地址：

@WebServlet(urlPatterns = {},loadOnStartup = 2)
public class WebPatInitServlet extends HttpServlet {
    @Override
    public void init(ServletConfig config) throws ServletException {
        //在整个应用中上下文使用webpath来存储上下文路径
                      config.getServletContext().setAttribute("webpath",config.getServletContext().getContextPath());
        super.init(config);
    }
}
//loadonstartup =2 是为了让这个servlet最快加载，可以优先获取到webpath

表单访问：

<form action="${webpath}/test/p1" method="post" >
        <input type="submit">
</form>
<!--      以前的写法  ------->
 <form action="${pageContext.request.contextPath}/test/p1" method="post" onsubmit="">
        <input type="submit">
 </form>

• @ResponseBody (在请求页面返回数据)

  @ResponseBody
  public String put(){
      return "put";
  }
  

• @ModelAttribute

  默认初始化信息：

  若前端jsp有传值，则使用前端传入的值，否则则使用@ModelAttribute注解下的默认初始化值

  @ModelAttribute
  public void init(Model model){
      System.out.println("initing.........");
      User u=new User();
      u.setUsername("linpr");
      model.addAttribute("user",u);
  }
  
  @RequestMapping("p5")
  @ResponseBody
  public String MA(User user){
      System.out.println(user.getUsername());
      return user.getUsername();
  }
  

<form action="${webpath}/test/p5" method="post" >
    <input type="text" name="username">
    <input type="submit">
</form>

• @SessionAttributes

  ​ 添加到类上面，在session中放置模型

  @Controller
  @RequestMapping("/test")
  @SessionAttributes("user")
  public class TestController {
  @RequestMapping("p8")
      public String redirecttojsp(User user){
          System.out.println("重定向");
          return "redirect:/index.jsp";
      }
   }
  

  jsp中：

${sessionScope.user.username}

• @SessionAttribute

  登录的狗会被注册的狗给覆盖，只有进行了注册才能进行登录，且只能登录当前注册账号

  @Controller
  @RequestMapping("/dog")
  @SessionAttributes("dog")
  public class DogController {
      @RequestMapping("/register")
      @ResponseBody
      public String  register(Dog dog){
          System.out.println("注册的狗名为:"+dog.getName());
          return dog.getName();
      }
      //会检查当前会话中是否含有Dog对象，如果，则会出现400错误
      @RequestMapping("/login")
      public String login(@SessionAttribute Dog dog){
          System.out.println(" 登录的名字"+dog.getName());
          return "dog";
      }
  }
  

• @PathVariable注解

 @RequestMapping("/restful/{id}/{name}")
    public void test(@PathVariable("id")Integer id,@PathVariable("name")String name){
        System.out.println("id为："+id+"姓名为："+name);

    }

• @RestController=@Controller+@Responsebody //当该Controller全是返回数据的方法时，可直接使用@RestController

• @Requestbody

  用来前台传递json数据到后台，使用方式

  $('#b1').click(function () {
                  var obj={
                  "username":"周振昭",
                      "password":"goudongxi"
                  }
                  $.ajax({
                          url: '${webpath}/Json2/m1',
                          type: 'post',
                          contentType:'application/json',
                          data:JSON.stringify(obj),
                          success: function (data) {
                          }
                      }
                  )
              })

  @Controller
  @RequestMapping("Json2")
  public class JsonController2 {
      @RequestMapping("m1")
      public String t1(@RequestBody User user){
          System.out.println(user.getUsername()+user.getPassword());
          return null;
      }
  }