From bd3884c617e1a8528cd5f4a72924417efd221b1f Mon Sep 17 00:00:00 2001
From: wu xiangkai <wuxiangkai@yonyou.com>
Date: Wed, 30 Nov 2022 16:50:59 +0800
Subject: [PATCH] =?UTF-8?q?=E6=97=A5=E5=B8=B8=E6=8F=90=E4=BA=A4?=
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---
 spring/Spring core/SpringMVC.md | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/spring/Spring core/SpringMVC.md b/spring/Spring core/SpringMVC.md
index e311c37..a1897ed 100644
--- a/spring/Spring core/SpringMVC.md	
+++ b/spring/Spring core/SpringMVC.md	
@@ -325,6 +325,39 @@ public String update(@Valid AccountForm form, BindingResult result,
     // ...
 }
 ```
+#### @SessionAttributes
+@SessionAttributes注解用于将model attribute存储在http session中，从而在不同的请求间都可以访问该attribute。  
+@SessionAttributes为class-level的注解，注解的value应该列出model attribute name或model attribute的类型。  
+该注解使用如下所示：
+```java
+@Controller
+@SessionAttributes("pet") 
+public class EditPetForm {
+
+    // ...
+
+    @PostMapping("/pets/{id}")
+    public String handle(Pet pet, BindingResult errors, SessionStatus status) {
+        if (errors.hasErrors) {
+            // ...
+        }
+        status.setComplete(); 
+        // ...
+    }
+}
+```
+当第一个请求到来时，name为pet的Model Attribute被添加到model中，其会被自动提升并保存到http session中，知道另一个controller method通过SessionStatus方法来清除存储。
+#### @SessionAttribute
+如果想要访问已经存在的Session Attribute，可以在handler method的参数上添加@SessionAttribute，如下所示：
+```java
+@RequestMapping("/")
+public String handle(@SessionAttribute User user) { 
+    // ...
+}
+```
+#### Multipart
+在MultipartResolver被启用之后，
+