Spring MVC之Controller

【注】默认按照约定寻找servlet.xml配置文件，如果需要指定或者需要增加多个servlet的配置该如何处理呢？方法如下：

<servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <!-- <param-value>classpath:/spring-core.xml</param-value> -->
            <!-- <param-value>/WEB-INF/classes/servlet1.xml,/WEB-INF/classes/servlet2.xml</param-value> -->
            <!-- <param-value>/WEB-INF/classes/servlet*.xml</param-value> -->
            <param-value>/WEB-INF/classes/spring/*.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

1、直接转发的controller，不需要再实现无任何行为的controller类,登录常用.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:lang="http://www.springframework.org/schema/lang"
    xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-2.5.xsd">

    <bean id="LoginSpringAction" class="com.alibaba.spring.LoginSpringAction"></bean>
    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="start.test">LoginSpringAction</prop>
                <prop key="login.test">LoginAction</prop>
            </props>
        </property>
    </bean>
    <bean id="LoginAction" class="org.springframework.web.servlet.mvc.ParameterizableViewController">
        <property name="viewName" value="login"></property>
    </bean>

    <bean class="org.springframework.web.servlet.view.UrlBasedViewResolver">
        <property name="viewClass"
            value="org.springframework.web.servlet.view.JstlView"></property>
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

查找过程：LoginAction->ParameterizableViewController->login->/WEB-INF/jsp/login.jsp

2、请求URL与要找的资源名称一致时，使用更简单的UrlFilenameViewController

<bean id="LoginAction" class="org.springframework.web.servlet.mvc.UrlFilenameViewController"/>

请求http://localhost:8080/login.test， 通过login.test->LoginAction ->UrlFilenameViewController->解析url，分析出login，再根据规则跳转到login.jsp中

3、封装表单参数的控制器：AbstractCommandController。【注】在spring3.0标注为过期，更建议使用注解。2.5版本未过期。

步骤1：表单提交：<form method="get" action="dispEmp.test"> 

步骤2：继承AbstractCommandController类

public class EmployeeController extends AbstractCommandController {

    @Override
    protected ModelAndView handle(HttpServletRequest request, HttpServletResponse response,
                                  Object command, BindException errors) throws Exception {
        Employee employee = (Employee)command;
        System.out.println(employee);
        return new ModeAndView("displayEmp");
    }
}

步骤3：配置CommandController类，【注】需要在里面配置属性：commandClass， 原因是根据反射的原理进行实例化类，再set其属性的

<bean id="EmployeeAction" class="com.alibaba.spring.EmployeeController">
        <property name="commandClass" value="com.alibaba.spring.Employee"></property>
    </bean>

    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="dispEmp.test">EmployeeAction</prop>
            </props>
        </property>
    </bean>

 提交到dispEmp.test->EmployeeAction->EmployeeController->commandClass->Employee，执行其set方法将属性赋值。

问题1：Date类型的数据绑定，比如增加了hireDate且格式自定义怎么办呢？方法有2种，其一：自定义属性编辑器注入到AbstractCommandController的方法initBinder中

@Override
    protected void initBinder(HttpServletRequest request, ServletRequestDataBinder binder)
            throws Exception {
        binder.registerCustomEditor(Date.class, new MyPropertyEditor());
    }

其中：CustomDateEditor代码如下：

public class MyPropertyEditor extends PropertyEditorSupport {
    String format = "yyyy-MM-dd";

    public void setFormat(String format) {
        this.format = format;
    }

    @Override
    public void setAsText(String text) throws IllegalArgumentException {
        SimpleDateFormat dateFormat = new SimpleDateFormat(format);
        System.out.println("--->" + text);
        try {
            Date date = dateFormat.parse(text);
            this.setValue(date);
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

 

其二：使用spring提供的半成品：CustomDateEditor

@Override
   protected void initBinder(HttpServletRequest request, ServletRequestDataBinder binder)
           throws Exception {
       //binder.registerCustomEditor(Date.class, new MyPropertyEditor());
       binder.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat(
               "yyyy-MM-dd"), true));
   }

 4、另外的获取表单参数的类：SimpleFormController，其onSubmit方法，只有post提交的时候才会执行