在讲用纯注解的方式实现springmvc之前先介绍一个类：AbstractAnnotationDispatcherServletInitializer.这个类的作用是：任何一个类继承AbstractAnnotationDispatcherServletInitializer,将会自动的被用为配置DispatcherServlet,以及在DispatcherServlet中的的spring容器（如：spring-servlet.xml）文件。
spring in action的描述是：any class that extends AbstractAnnotationDispatcherServletInitializer will automatically be used to configure DispatcherServlet and the Spring Application context in the application's servlet context.
AbstractAnnotationDispatcherServlet的代码如下：
/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/ package org.springframework.web.servlet.support; import org.springframework.util.ObjectUtils;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext; /**
* Base class for {@link org.springframework.web.WebApplicationInitializer}
* implementations that register a
* {@link org.springframework.web.servlet.DispatcherServlet DispatcherServlet}
* configured with annotated classes, e.g. Spring's
* {@link org.springframework.context.annotation.Configuration @Configuration} classes.
*
* <p>Concrete implementations are required to implement {@link #getRootConfigClasses()}
* and {@link #getServletConfigClasses()} as well as {@link #getServletMappings()}.
* Further template and customization methods are provided by
* {@link AbstractDispatcherServletInitializer}.
*
* <p>This is the preferred approach for applications that use Java-based
* Spring configuration.
*
* @author Arjen Poutsma
* @author Chris Beams
* @since 3.2
*/
public abstract class AbstractAnnotationConfigDispatcherServletInitializer
extends AbstractDispatcherServletInitializer { /**
* {@inheritDoc}
* <p>This implementation creates an {@link AnnotationConfigWebApplicationContext},
* providing it the annotated classes returned by {@link #getRootConfigClasses()}.
* Returns {@code null} if {@link #getRootConfigClasses()} returns {@code null}.
*/
@Override
protected WebApplicationContext createRootApplicationContext() {
Class<?>[] configClasses = getRootConfigClasses();
if (!ObjectUtils.isEmpty(configClasses)) {
AnnotationConfigWebApplicationContext rootAppContext = new AnnotationConfigWebApplicationContext();
rootAppContext.register(configClasses);
return rootAppContext;
}
else {
return null;
}
} /**
* {@inheritDoc}
* <p>This implementation creates an {@link AnnotationConfigWebApplicationContext},
* providing it the annotated classes returned by {@link #getServletConfigClasses()}.
*/
@Override
protected WebApplicationContext createServletApplicationContext() {
AnnotationConfigWebApplicationContext servletAppContext = new AnnotationConfigWebApplicationContext();
Class<?>[] configClasses = getServletConfigClasses();
if (!ObjectUtils.isEmpty(configClasses)) {
servletAppContext.register(configClasses);
}
return servletAppContext;
} /**
* Specify {@link org.springframework.context.annotation.Configuration @Configuration}
* and/or {@link org.springframework.stereotype.Component @Component} classes to be
* provided to the {@linkplain #createRootApplicationContext() root application context}.
* @return the configuration classes for the root application context, or {@code null}
* if creation and registration of a root context is not desired
*/
protected abstract Class<?>[] getRootConfigClasses(); /**
* Specify {@link org.springframework.context.annotation.Configuration @Configuration}
* and/or {@link org.springframework.stereotype.Component @Component} classes to be
* provided to the {@linkplain #createServletApplicationContext() dispatcher servlet
* application context}.
* @return the configuration classes for the dispatcher servlet application context or
* {@code null} if all configuration is specified through root config classes.
*/
protected abstract Class<?>[] getServletConfigClasses(); }
案例的目录结构如下图所示：
RootConfig的代码如下：
package spittr.config; import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.servlet.config.annotation.EnableWebMvc; /**
* Created by ${秦林森} on 2017/6/12.
*/
@Configuration
/**
* excludeFilters是指明不被@ComponentScan扫描的类型
*/
@ComponentScan(basePackages = {"spittr"},excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,value = EnableWebMvc.class)}) public class RootConfig { }
WebConfig的代码如下：
package spittr.config; import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.BeanNameViewResolver;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import spittr.web.HomeController; /**
* Created by ${秦林森} on 2017/6/12.
*/
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"spittr.web"})
public class WebConfig extends WebMvcConfigurerAdapter{
@Bean
public ViewResolver viewResolver(){
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
//设置前缀
viewResolver.setPrefix("/WEB-INF/views/");
//设置后缀
viewResolver.setSuffix(".jsp");
viewResolver.setExposeContextBeansAsAttributes(true);
return viewResolver;
}
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
configurer.enable();//configure static content handling.
} }
package spittr.config; import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer; /**
* Created by ${秦林森} on 2017/6/12.
*/
public class SpittrWebApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer { @Override
protected Class<?>[] getRootConfigClasses() {
return new Class<?>[]{RootConfig.class};
} @Override
protected Class<?>[] getServletConfigClasses() {
//specifiy configuration class
return new Class<?>[]{WebConfig.class};
} @Override
protected String[] getServletMappings() {
return new String[]{"*.do"};//Map DispatcherServlet to
}
}
HomeController的代码如下：
package spittr.web; import org.springframework.stereotype.Controller;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod; /**
* Created by ${秦林森} on 2017/6/12.
*/
@Controller
@RequestMapping(value = "/people")
public class HomeController {
@RequestMapping(value = "/home.do",method = RequestMethod.GET)
public String home(){
return "home";
}
}
home.jsp的代码如下：
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2017/6/12
Time: 16:25
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>spittr</title>
</head>
<body>
welcome to china ,one of the ancient civilized countries.
</body>
</html>
注意我这个项目的web应用名设置为该项目名。
启动tomcat 输入：http://localhost:8090/spring20170602/people/home.do
访问结果如下图所示: