springMVC数据传递

超、凢脫俗 2023-06-28 06:17 44阅读 0赞

**1 @RequestMapping的用法**  
可以放在类上也可以放在方法上,参数可以是一个字符串,也可以是字符串数组

@Controller
    @RequestMapping(value = "/test")
    public class HomeController {
        @RequestMapping(value = "/hello")
        public String hello(){
            return "index";
        }
    }
    
    @Controller
    @RequestMapping({"/test","test1"})
    public class HomeController {
         ……
    }

**2 传递模型数据到前端页面**  
**1)返回前端页面路径**

@RequestMapping(value = "/hello")
    public String hello(Model model){
        List<Spittle> list = new ArrayList<Spittle>();
        model.addAttribute(list);
        return "index";
    }

注:当调用addAttribute()方法不指定key时,那么key会根据值得对象类型推断确定,在上例中值是List,那么键值将是spittleList.如果想要显式得声明键值,这可以使用model.addAttribute(“spittleList”,list);如果不想使用model,也可以将其换成map,代码如下:

@RequestMapping(value = "/hello1")
    public String hello1(Map map){
        List<Spittle> list = new ArrayList<Spittle>();
        map.put("spittleList",list);
        return "index";
    }

**2)直接返回数据到前端页面**

@Controller
    @RequestMapping({"/test","test1"})
    public class HomeController {
        @RequestMapping(value = "/hello2")
        public List<Spittle> hello2(Map map){
            List<Spittle> list = new ArrayList<Spittle>();
            map.put("spittleList",list);
            return list;
        }
    }

如果请求路径为:http://localhost:8080/test/hello2那么将会返回到webapp/WEB-INF/views/test/hello2.html这个视图,其中webapp/WEB-INF/views为Prefix路径

**3重定向数据传递**  
**1)简单的数据传递**

@Controller
    @RequestMapping({"/test","test1"})
    public class HomeController {
        @RequestMapping(value = "/hello3")
        public String hello3(Map map){
            map.put("userName", "adadfasfdas");
            map.put("userId", "111111");
            return "redirect:/test/hello/{userId}";
        }
        ……
    }
    
    @RequestMapping(value = "/hello/{userId}")
    public String hello(@PathVariable("userId")String userId, @RequestParam("userName") String userName){
        System.out.println(userName);
        System.out.println(userId);
        return "index";
    }

测试  
请求地址:http://localhost:8080/test/hello3  
最终重定向后浏览器地址:http://localhost:8080/test/hello/111111?userName=adadfasfdas  
管理台日志:  
![在这里插入图片描述][20200107193519753.png]

**2)使用flash属性**

@RequestMapping(value = "/hello4")
    public String hello4(RedirectAttributes model){
        Map<String, String> userMap = new HashMap<String, String>();
        userMap.put("userName", "adadfasfdas");
        userMap.put("userId", "111111");
        model.addFlashAttribute("userMap", userMap);
        model.addAttribute("userId", "111111");
        return "redirect:/test/hello/{userId}";
    }
    
    @RequestMapping(value="/hello/{userId}")
    publicStringhello(@PathVariable("userId")StringuserId,Modelmodel){
    Map<String,String>userMap=(HashMap<String,String>)model.asMap().get("userMap");
    System.out.println(userMap.get("userName"));
    System.out.println(userId);
    return"index";
    }

测试  
请求地址:http://localhost:8080/test/hello4  
最终重定向后浏览器地址:http://localhost:8080/test/hello/111111  
管理台日志:  
![在这里插入图片描述][20200107193618453.png]

[20200107193519753.png]: https://img-blog.csdnimg.cn/20200107193519753.png
[20200107193618453.png]: https://img-blog.csdnimg.cn/20200107193618453.png