MultiActionController 與 PropertiesMethodNameResolver


您 也可以將所有相對應的方法專門組織在一個委託（delegate）物件中，而不是撰寫在Controller類別中，當請求來到時，將委託給這個物件來執 行指定的方法，您只要設定MultiActionController的"delegate"屬性參考至委託物件即可，例如委託物件可以設計如下：
  • BookDelegate.java
package onlyfun.caterpillar; 

import javax.servlet.http.*; 
import org.springframework.web.servlet.ModelAndView;

public class BookDelegate { 
    private String testPage; 
    
    public ModelAndView list(HttpServletRequest req, 
                          HttpServletResponse res) { 
        return new ModelAndView(
                this.getTestPage(),"executed", "list"); 
    } 
    
    public ModelAndView add(HttpServletRequest req, 
                           HttpServletResponse res) { 
        return new ModelAndView(
                this.getTestPage(),"executed", "add"); 
    } 
    
    public ModelAndView delete(HttpServletRequest req, 
                             HttpServletResponse res) { 
        return new ModelAndView(
                this.getTestPage(),"executed", "delete"); 
    } 
    
    public String getTestPage() { 
        return testPage; 
    } 
    
    public void setTestPage(String testPage) { 
        this.testPage = testPage; 
    } 
}

現在不用繼承MultiActionController類別來定義您的Controller類別了，而是在定義檔中直接定義一個MultiActionController的實例：
  • mvc-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC 
 "-//SPRING/DTD BEAN/EN" 
 "http://www.springframework.org/dtd/spring-beans.dtd"> 

<beans>   
    <bean id="urlMapping" 
          class="org.springframework.web.servlet.
                   → handler.SimpleUrlHandlerMapping"> 
        <property name="mappings"> 
            <props> 
                <prop key="/book.do">bookController</prop> 
            </props> 
        </property> 
    </bean> 
    
    <bean id="viewResolver" 
          class="org.springframework.web.servlet.
                   → view.InternalResourceViewResolver"> 
        <property name="prefix"> 
            <value>/WEB-INF/jsp/</value> 
        </property> 
        <property name="suffix"> 
            <value>.jsp</value> 
        </property> 
    </bean> 

    <bean id="paraMethodResolver" 
          class="org.springframework.web.servlet.mvc.
                   → multiaction.ParameterMethodNameResolver"> 
        <property name="paramName">
            <value>action</value>
        </property> 
        <property name="defaultMethodName">
            <value>list</value>
        </property> 
    </bean> 

   <bean id="bookDelegate" 
         class="onlyfun.caterpillar.BookDelegate"> 
        <property name="testPage"> 
            <value>test</value> 
        </property> 
    </bean> 
            
    <bean id="bookController" 
          class="org.springframework.web.servlet.mvc.
                   → multiaction.MultiActionController"> 
        <property name="methodNameResolver"> 
            <ref bean="paraMethodResolver"/> 
        </property> 
        <property name="delegate"> 
            <ref bean="bookDelegate"/> 
        </property> 
    </bean> 
</beans>

您可以使用 MultiActionController 與 ParameterMethodNameResolver 中的test.jsp網頁來呈現結果，這個程式的執行結果與 MultiActionController 與 ParameterMethodNameResolver 是相同的。

上面的程式，您也可以改使用PropertiesMethodNameResolver，例如將Bean定義檔的內容改寫為以下的內容：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC
 "-//SPRING/DTD BEAN/EN"
 "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>  
    <bean id="urlMapping"
          class="org.springframework.web.servlet.
                   → handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/*book.do">bookController</prop>
            </props>
        </property>
    </bean>
   
    <bean id="viewResolver"
          class="org.springframework.web.servlet.
                   → view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/jsp/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>

    <bean id="propMethodResolver"
        class="org.springframework.web.servlet.mvc.
                   → multiaction.PropertiesMethodNameResolver">
        <property name="mappings">
            <props>
                <prop key="/listbook.do">list</prop>
                <prop key="/addbook.do">add</prop>
                <prop key="/deletebook.do">delete</prop>
            </props>
        </property>
    </bean>

    <bean id="bookDelegate"
          class="onlyfun.caterpillar.BookDelegate">
        <property name="testPage">
            <value>test</value>
        </property>
    </bean>
           
    <bean id="bookController"
          class="org.springframework.web.servlet.mvc.
                   → multiaction.MultiActionController">
        <property name="methodNameResolver">
            <ref bean="propMethodResolver"/>
        </property>
        <property name="delegate">
            <ref bean="bookDelegate"/>
        </property>
    </bean>
</beans>

根據以上的設定，所有以book.do為結尾的請求都會交給bookController來處理，而當請求/listbook.do時，會執行 bookDelegate的list()方法，依同樣的道理，您可以分別使用/addbook.do或/deletebook.do來執行add()或 list()方法。