spring mvc 配置(xml配置详解)

    xiaoxiao2021-03-25  101

    如果您曾经使用Spring MVC框架开发过Web应用程序,本文提供关于Spring MVC框架的配置技巧,以帮助管理基于Spring的web应用程序的多个实例。

    web.xml 配置:

    1 2 3 4 5 6 7 8 9 10 11 12 13 14 <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>*.htm</url-pattern> </servlet-mapping>

    这样,所有的.htm的请求,都会被DispatcherServlet处理;

    初始化 DispatcherServlet 时,该框架在 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何Beans,像上面的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:

    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 <?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Controller

    1 2 3 4 5 6 7 8 9 10 11 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注解标记一个访问的路径(/index.htm),return "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,则标记访问的路径;

    @RequestMapping注解标记的访问路径中获取参数:

    Spring MVC 支持RESTful风格的URL参数,如:

    1 2 3 4 5 6 7 8 9 @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

    1 2 3 4 5 6 7 8 9 10 11 12 13 @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:

    1 return "redirect:/login2"

    可以传入方法的参数类型:

    1 2 3 4 5 6 @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:

    1 2 3 4 5 6 @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; }

    使用@RequestParam 注解获取GET请求或POST请求提交的参数;

    获取Cookie的值:使用@CookieValue 

    获取PrintWriter

    可以直接在Controller的方法中传入PrintWriter对象,就可以在方法中使用:

    1 2 3 4 5 @RequestMapping(value = "login" , method = RequestMethod.POST) public String testParam(PrintWriter out, @RequestParam( "username" ) String username) {      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):

    1 2 3 4 5 6 7 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:

    1 2 3 4 5 @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:

    1 2 3 4 5 @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):

    1 2 3 4 5 6 7 8 9 10 11 12 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

    1 2 3 4 5 6 <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"      p: basename = "message" > </bean>  

    转载请注明原文地址: https://ju.6miu.com/read-12940.html

    最新回复(0)