基于注解的SpringMVC

Web.xml配置

<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <description>加载/WEB-INF/spring-mvc/目录下的所有XML作为Spring MVC的配置文件</description>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring-mvc/*.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

这样,所有的.do请求,都会被DispatcherServlet处理;

初始化DispatcherServlet时,改框架在web应用程序WEB-INF目录中寻找一个名为[servlet-名称]-servlet.xml的文件,并在那里定义相关的Beans,重写在全局中定义的任务Beans,想上面的web.xml中的代码对应的是dispatcher-servlet.xml;当然也可以使用<init-param>元素,手动指定配置文件的路径。

dispatcher-servlet.xml配置:

<?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:mvc="http://www.springframework.org/schema/mvc"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="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
            http://www.springframework.org/schema/aop 
            http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
            http://www.springframework.org/schema/tx 
            http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
            http://www.springframework.org/schema/mvc 
            http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
            http://www.springframework.org/schema/context 
            http://www.springframework.org/schema/context/spring-context-3.0.xsd">
    <!--
        使Spring支持自动检测组件,如注解的Controller
    -->
    <context:component-scan base-package="com.minx.crm.web.controller"/>
   
    <bean id="viewResolver"
          class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          p:prefix="/WEB-INF/jsp/"
          p:suffix=".jsp" />
</beans>

第一个Contrioller:

package com.minx.crm.web.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class IndexController {
    @RequestMapping("/index")
    public String index() {
        return "index";
    }
}

@Controller注解标识一个控制器,@RequestMapping注解标记一个访问路径(/index.do),retuen"index"标记返回视图(index.jsp);

注:如果@RequestMapping注解在类级别上,则表示一相对路径,在方法级别上,则标记访问路径;

从@RequestMapping注解的标记的访问路径中获取参数:

Spring MVC支持RESTful风格的URL参数,如:

 

@Controller
public class IndexController {

    @RequestMapping("/index/{username}")
    public String index(@PathVariable("username") String username) {
        System.out.print(username);
        return "index";
    }
}

 

@RequestMapping中定义访问页面的URL模版,使用{}传入页面参数,使用@PathVariable 获取传入参数,即可通过地址:http://localhost:8080/crm/index/tanqimin.htm 访问;

 

根据不同的Web请求方法,映射到不同的处理方法:

 

使用登陆页面作示例,定义两个方法分辨对使用GET请求和使用POST请求访问login.htm时的响应。可以使用处理GET请求的方法显示视图,使用POST请求的方法处理业务逻辑

 

 

@Controller
public class LoginController {
    @RequestMapping(value = "/login", method = RequestMethod.GET)
    public String login() {
        return "login";
    }
    @RequestMapping(value = "/login", method = RequestMethod.POST)
    public String login2(HttpServletRequest request) {
            String username = request.getParameter("username").trim();
            System.out.println(username);
        return "login2";
    }
}

在视图页面,通过地址栏访问login.htm,是通过

GET请求访问页面,因此,返回登陆表单视图login.jsp;当在登陆表单中使用POST请求提交数据时,则访问login2方法,处理登陆业务逻辑;

防止重复提交数据,可以使用重定向视图:

 

return "redirect:/login2"

 

可以传入方法的参数类型:

@RequestMapping(value = "login", method = RequestMethod.POST)
public String testParam(HttpServletRequest request, HttpServletResponse response, HttpSession session) {
    String username = request.getParameter("username");
    System.out.println(username);
    return null;
}

可以传入HttpServletRequestHttpServletResponseHttpSession,值得注意的是,如果第一次访问页面,HttpSession没被创建,可能会出错;

其中,String username = request.getParameter("username");可以转换为传入的参数:

@RequestMapping(value = "login", method = RequestMethod.POST)
public String testParam(HttpServletRequest request, HttpServletResponse response, HttpSession session,@RequestParam("username") String username) {
    String username = request.getParameter("username");
    System.out.println(username);
    return null;
}

获取表单中提交的值,并封装到POJO中,传入Controller的方法里:

POJO如下(User.java):

 

public class User{
    private long id;
    private String username;
    private String password;

    …此处省略getter,setter...
}

 

通过表单提交,直接可以把表单值封装到User对象中:

 

@RequestMapping(value = "login", method = RequestMethod.POST)
public String testParam(PrintWriter out, User user) {
    out.println(user.getUsername());
    return null;
}

 

可以把对象,put 入获取的Map对象中,传到对应的视图:

@RequestMapping(value = "login", method = RequestMethod.POST)
public String testParam(User user, Map model) {
    model.put("user",user);
    return "view";
}

在返回的view.jsp中,就可以根据key来获取user的值(通过EL表达式,${user }即可);

Controller中方法的返回值:

void:多数用于使用PrintWriter输出响应数据;

String 类型:返回该String对应的View Name

任意类型对象:

返回ModelAndView

自定义视图(JstlViewExcelView):

拦截器(Inteceptors):

public class MyInteceptor implements HandlerInterceptor {
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) 
        throws Exception {
        return false;
    }
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object o, ModelAndView mav) 
        throws Exception {
    }
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object o, Exception excptn) 
        throws Exception {
    }
}

拦截器需要实现HandleInterceptor接口,并实现其三个方法:

preHandle:拦截器的前端,执行控制器之前所要处理的方法,通常用于权限控制、日志,其中,Object o表示下一个拦截器;

postHandle:控制器的方法已经执行完毕,转换成视图之前的处理;

afterCompletion:视图已处理完后执行的方法,通常用于释放资源;

MVC的配置文件中,配置拦截器与需要拦截的URL

 

<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/index.htm" />
        <bean class="com.minx.crm.web.interceptor.MyInterceptor" />
    </mvc:interceptor>
</mvc:interceptors>

 

国际化:

MVC配置文件中,配置国际化属性文件:

 

<bean id="messageSource"
    class="org.springframework.context.support.ResourceBundleMessageSource"
    p:basename="message">
</bean>

 

那么,Spring就会在项目中搜索相关的国际化属性文件,如:message.propertiesmessage_zh_CN.properties

VIEW中,引入Spring标签:<%@taglib uri="http://www.springframework.org/tags" prefix="spring" %>,使用<spring:message code="key" />调用,即可;

如果一种语言,有多个语言文件,可以更改MVC配置文件为:

 

<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
    <property name="basenames">
        <list>
            <value>message01</value>
            <value>message02</value>
            <value>message03</value>
        </list>
    </property>
</bean>

 

 

 

 

 

 

 

 

posted on 2014-02-28 11:09  java界的奥特曼  阅读(203)  评论(0编辑  收藏  举报