java - Spring 3基于Java的配置，替换XML

Question

我最近配置了基于 spring 的 Maven 项目，我只想用 java 替换所有 XML(POM 除外)。我探索了很多与此相关的文章和文档，但是，我来这里的原因是，我有疑问，我认为你们可以解决这些疑问。

众所周知，每个动态 Web 项目都有一个 XML，在没有框架的情况下称为 web.xml。

现在如果我们集成一些框架，比如 Struts、Spring、ORM 等。还需要配置这些，因此我们编写另一个 XML 配置文件。

我配置了 spring 项目，因此我有一个部署描述符、应用程序上下文和调度程序 servlet。

WEB.XML

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/app-ctx.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
     <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>redirect.jsp</welcome-file>
    </welcome-file-list>
</web-app>

app-ctx.xml

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:flow="http://www.springframework.org/schema/webflow-config"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:jms="http://www.springframework.org/schema/jms"
       xmlns:lang="http://www.springframework.org/schema/lang"
       xmlns:osgi="http://www.springframework.org/schema/osgi"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:tx="http://www.springframework.org/schema/tx"

       xsi:schemaLocation="http://www.springframework.org/schema/beans 
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/aop 
                           http://www.springframework.org/schema/aop/spring-aop.xsd
                           http://www.springframework.org/schema/context  
                           http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/webflow-config 
                           http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.0.xsd
                           http://www.springframework.org/schema/jee 
                           http://www.springframework.org/schema/jee/spring-jee.xsd
                           http://www.springframework.org/schema/jms 
                           http://www.springframework.org/schema/jms/spring-jms.xsd
                           http://www.springframework.org/schema/lang 
                           http://www.springframework.org/schema/lang/spring-lang.xsd
                           http://www.springframework.org/schema/osgi 
                           http://www.springframework.org/schema/osgi/spring-osgi.xsd
                           http://www.springframework.org/schema/tx 
                           http://www.springframework.org/schema/tx/spring-tx.xsd
                           http://www.springframework.org/schema/util 
                           http://www.springframework.org/schema/util/spring-util.xsd">

    <context:component-scan base-package="com.mzk.mavenproject1"/>

<!--    <bean id="propertyConfigurer"
          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
          p:location="/WEB-INF/config_local.properties" />-->


</beans>

dispatcher-servlet.xml

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:c="http://www.springframework.org/schema/c"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:flow="http://www.springframework.org/schema/webflow-config"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:jms="http://www.springframework.org/schema/jms"
       xmlns:lang="http://www.springframework.org/schema/lang"
       xmlns:osgi="http://www.springframework.org/schema/osgi"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:util="http://www.springframework.org/schema/util"

       xsi:schemaLocation="http://www.springframework.org/schema/beans 
                           http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/aop 
                           http://www.springframework.org/schema/aop/spring-aop.xsd
                           http://www.springframework.org/schema/context  
                           http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/mvc 
                           http://www.springframework.org/schema/mvc/spring-mvc.xsd
                           http://www.springframework.org/schema/webflow-config 
                           http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.0.xsd
                           http://www.springframework.org/schema/jee 
                           http://www.springframework.org/schema/jee/spring-jee.xsd
                           http://www.springframework.org/schema/jms 
                           http://www.springframework.org/schema/jms/spring-jms.xsd
                           http://www.springframework.org/schema/lang 
                           http://www.springframework.org/schema/lang/spring-lang.xsd
                           http://www.springframework.org/schema/osgi 
                           http://www.springframework.org/schema/osgi/spring-osgi.xsd
                           http://www.springframework.org/schema/tx 
                           http://www.springframework.org/schema/tx/spring-tx.xsd
                           http://www.springframework.org/schema/util 
                           http://www.springframework.org/schema/util/spring-util.xsd">

    <mvc:resources mapping="/resources/**" location="/resources/"  cache-period="31556926" />
    <context:component-scan base-package="com.mzk.mavenproject1"/>

    <mvc:annotation-driven content-negotiation-manager="contentNegotiationManager"/>    

    <bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
        <!--Turn off working out content type based on URL file extension, should fall back to looking at the Accept headers-->
        <property name="favorPathExtension" value="false" />
    </bean>   

    <!-- 2. HandlerMapping : Used default handler mapping internally -->

    <!-- 3. ViewResolver -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>   

</beans>

困惑:

我很困惑地知道，我们到底需要替换多少个 java 类。我们需要三个 java 类还是两个类就足够了？

因为很多文章都演示了这两个java类，分别替换了web.xml和dispatcher-servlet.xml，那么app-ctx呢.xml？

编辑:

 @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addRedirectViewController("/", "home");
    }

或者

@Override
        public void addViewControllers(ViewControllerRegistry registry) {
           registry.addViewController("/").setViewName("home");
        }

Controller 类别

@Controller
public class HomeController {

    @RequestMapping(value="/")
    public ModelAndView showhomePage() {
        ModelAndView mav = new ModelAndView("home");
        mav.addObject("successMsg", "Congratulations! Your Cortana is Properly congigured");
        return mav;
    }
}

我还做了一个技巧，我创建了一个全局 index.jsp，并仅指定一个 scriptlet，该脚本将使用 `sendRedirect() 将请求重定向到 Controller 。

喜欢

@Override
            public void addViewControllers(ViewControllerRegistry registry) {
               registry.addViewController("/").setViewName("forward:/index.jsp");
            }

没有代码片段对我有用，每次我面对 404 时，我想我错过了什么？

Answer 1

如果我理解得很好，你想摆脱所有 XML 配置。

然后首先您必须实现 WebApplicationInitializer 来替换 web.xml 配置文件。你可以这样做:

public class CustomWebAppInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
        rootContext.register(RootConfig.class);

        ContextLoaderListener contextLoaderListener = new ContextLoaderListener(rootContext);
        servletContext.addListener(contextLoaderListener);

        AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext();
        webContext.register(MvcConfig.class);

        DispatcherServlet dispatcherServlet = new DispatcherServlet(webContext);
        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", dispatcherServlet);
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");
    }
}

另一个步骤是为根上下文实现 Spring 配置，替换 app-ctx.xml:

@Configuration
@EnableWebMvc
@ComponentScan({"com.mzk.mavenproject1.service", "com.mzk.mavenproject1.model"})
public class RootConfig {
// ... provide another custom beans when needed
}

最后一步是实现 MVC 的配置，替换 dispatcher-servlet.xml:

@Configuration
@EnableWebMvc
@ComponentScan("com.mzk.mavenproject1.controller")
public class MvcConfig extends WebMvcConfigurerAdapter {
    @Bean
    ViewResolver internalViewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        return resolver;
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
    }

// ... provide another custom beans when needed
}

---

关于您关于类计数的问题 - 是的，您只能通过两个类来完成:CustomWebAppInitializer 和 MvcConfig 并且所有内容只有一个上下文。

CustomWebAppInitializer.onStartup() 方法主体将如下所示:

    AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext();
    webContext.register(MvcConfig.class);

    ContextLoaderListener contextLoaderListener = new ContextLoaderListener(webContext);
    servletContext.addListener(contextLoaderListener);

    DispatcherServlet dispatcherServlet = new DispatcherServlet(webContext);
    ServletRegistration.Dynamic dispatcher = servletContext.addServlet("dispatcher", dispatcherServlet);
    dispatcher.setLoadOnStartup(1);
    dispatcher.addMapping("/");