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"; } }
在@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HttpServletRequest、HttpServletResponse、HttpSession,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(JstlView,ExcelView):
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;
在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:
在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.properties、message_zh_CN.properties
在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>