一、

  Spring MVC的配置檔案Springmvc-servlet.xml報錯，在新增

<context:component-scan base-package="controller" />

Multiple annotations found at this line:
    - schema_reference.4: Failed to read schema document 'http://www.springframework.org/schema/
     springcontext.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root
     element of the document is not <xsd:schema>.
    - cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element
     'context:component-scan'.

  經過檢查，發現時springmvc-servlet的頭中，關於名稱空間（是不是這麼說的。。。）的定義有誤，導致找不到我對應的檔案。

  之前，我的頭定義如下：

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:p="http://www.springframework.org/schema/p"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
	                    http://www.springframework.org/schema/beans/spring-beans.xsd
	                    http://www.springframework.org/schema/mvc
	                    http://www.springframework.org/schema/mvc/spring-mvc.xsd
	                    http://www.springframework.org/schema/context
	                    http://www.springframework.org/schema/springcontext.xsd">
 

<beans xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd ">
 

二、依然是坑爹的配置bug

 我在實驗一個簡單的Spring MVC的demo的時候，所有的程式碼和jar、環境均已經搞定，但是run as server之後，出現：

org.xml.sax.SAXParseException; lineNumber: 12; columnNumber: 75; cvc-elt.1: 找不到元素 'beans' 的宣告

在實驗切xmlns中的檔案版本等等方法之後，依然沒有效果。但是奇怪的是，我之前一個類似的專案，該配置檔案極其類似，只是從傳統控制器風格變成了使用註解控制器，程式並沒有報錯！

後修改，在beans元素前面加上一個名稱空間beans，然後就不報錯了。

前後對比圖如下：

1.發生錯誤的時候：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" 
	xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc 
	    http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
		http://www.springframework.org/schema/beans 
		http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/context 
		http://www.springframework.org/schema/context/spring-context-3.0.xsd">
		
		 
	                
	<mvc:annotation-driven/>   
    <!-- ①：對web包中的所有類進行掃描，以完成Bean建立和自動依賴注入的功能 -->
    <context:component-scan base-package="controller" />
    <mvc:resources mapping="/*.html" location="/"/>
    
    <bean id="viewResolver"
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
	  <property name="prefix" value="/WEB-INF/jsp/" />
	  <property name="suffix" value=".jsp" />
	</bean>
</beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd ">
	<mvc:annotation-driven />
	<!-- ①：對web包中的所有類進行掃描，以完成Bean建立和自動依賴注入的功能 -->
	<context:component-scan base-package="net.use" />

	<!-- 這兩個類用來啟動基於Spring MVC的註解功能，將控制器與方法對映加入到容器中 -->
	<beans:bean
		class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
	<beans:bean
		class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

	<!-- 這個類用於Spring MVC檢視解析 -->
	<beans:bean id="viewResolver"
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<beans:property name="prefix" value="/WEB-INF/pages/" />
		<beans:property name="suffix" value=".jsp" />
	</beans:bean>
	
</beans:beans>

坑爹。。。

到現在還不知道是什麼原因。

3.今天準備嘗試一下實現依賴注入，途中發生了一個有趣的bug。

嚴重: Servlet.service() for servlet [s nested exception is org.springframewo

主要是怎麼回事呢。

說表單資料提交後自動繫結到User類的時候發生了一個錯誤，無法從String物件轉換成自己定義的Connection物件。

恍然想起來，form提交到伺服器的全部是String，但是我們自己定義的類的屬性可能是double,可能是一個物件。

所以為了解決這個問題，參考了之前看到的某篇文章，在轉成User類之前，先換成一個所有屬性都用String表示，屬性值和User類一一對應的UserForm類。如下：

package net.use.info;

import java.io.Serializable;

import net.use.connection.Connection;

public class User implements Serializable {
	/**
	 * @author zjn
	 */
	private static final long serialVersionUID = 1L;
	private String name; // name
	private String pwd; // pwd
	private Integer age; // age
	
	private String sex;
	
	private Connection connection;//connection是介面
	//全部實現了set和get方法�? 以此完成依賴注入（設值注入）
	public String getSex() {
		return sex;
	}

	public void setSex(String sex) {
		this.sex=sex;
	}


	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPwd() {
		return pwd;
	}

	public void setPwd(String pwd) {
		this.pwd = pwd;
	}

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}

	public Connection getConnection() {
		return connection;
	}

	public void setConnection(Connection connection) {
		this.connection = connection;
	}

}

package net.use.form;

public class UserForm {
	private String name; // name
	private String pwd; // pwd
	private Integer age; // age
	
	private String sex;
	
	private String connection;//connection是介面
	private String connection_type;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public String getConnection() {
		return connection;
	}
	public void setConnection(String connection) {
		this.connection = connection;
	}
	public String getConnection_type() {
		return connection_type;
	}
	public void setConnection_type(String connection_type) {
		this.connection_type = connection_type;
	}
	
	

}

	@RequestMapping("register")
	public String Save(@ModelAttribute("form") UserForm userForm, Model model) { // user:檢視層傳給控制層的表單物件；model：控制層返回給檢視層的對�?
		//model.addAttribute("user", user);
		//System.out.println(user.getName()+","+user.getSex()+","+user.getPwd()+","+user.getAge());
		
		//first,to convert the userform to the user
		User user = new User();
		user.setName(userForm.getName());
		user.setAge(userForm.getAge());
		user.setSex(userForm.getSex());
		user.setPwd(userForm.getPwd());
		
		Connection con;
		if(userForm.getConnection_type().equals("phone")) {
			con = new Phone();
			con.setNumber(userForm.getConnection());
			user.setConnection(con);
		}else if(userForm.getConnection_type().equals("msn")) {
			con = new MSN();
			con.setNumber(userForm.getConnection());
			user.setConnection(con);
		}