pure parameter object°

Author: seaswalker

note/spring-mvc.md

@@ -1187,4 +1187,18 @@ HandlerMethodReturnValueHandler接口以及主要实现类如下:
 
 从中也可以推测出我们可以把哪些类型的值(对象)直接"丢给"Spring。
 
-对于HandlerMethodArgumentResolver和HandlerMethodReturnValueHandler来说，HttpMessageConverter像是两者手中用来实现功能的武器。
+对于HandlerMethodArgumentResolver和HandlerMethodReturnValueHandler来说，HttpMessageConverter像是两者手中用来实现功能的武器。
+
+## "纯"对象参数接收
+
+假设有如下这样的Controller:
+
+```java
+@RequestMapping("/echoAgain")
+public String echo(SimpleModel simpleModel, Model model) {
+    model.addAttribute("echo", "hello " + simpleModel.getName() + ", your age is " + simpleModel.getAge() + ".");
+    return "echo";
+}
+```
+
+经过测试可以发现，SimpleModel参数既可以接收get请求，也可以接收post请求。那么在这种情况下请求参数是被哪个参数解析器解析的呢，debug发现: ServletModelAttributeMethodProcessor

src/main/java/controller/SimpleController.java

@@ -1,5 +1,6 @@
 package controller;
 
+import model.SimpleModel;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -18,4 +19,10 @@ public String echo(String name, Model model) {
         return "echo";
     }
 
+    @RequestMapping("/echoAgain")
+    public String echo(SimpleModel simpleModel, Model model) {
+        model.addAttribute("echo", "hello " + simpleModel.getName() + ", your age is " + simpleModel.getAge() + ".");
+        return "echo";
+    }
+
 }

src/main/java/model/SimpleModel.java

@@ -0,0 +1,29 @@
+package model;
+
+/**
+ * 简单的model.
+ *
+ * @author skywalker
+ */
+public class SimpleModel {
+
+    private String name;
+    private Integer age;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+
+}