SpringMVC基于代码的配置方式（零配置，无web.xml）直接继承WebMvcConfigurerAdapter

基于配置文件的web项目维护起来可能会更方便，但是有时候我们会有一些特殊的需求，比如防止客户胡乱更改配置，这时候我们需要给配置隐藏到代码中。

1.创建一个动态web项目（无需web.xml）

2.右键项目添加几个package: com.easyweb.config (保存项目配置) com.easyweb.controller （保存springMvc controller）

3.在 com.easyweb.config 新建一个类 WebApplicationStartup ，这个类实现WebApplicationInitializer 接口，是项目的入口，作用类似于web.xml，具体代码如下：

<code class="hljs" java="">package com.easyweb.config;

import javax.servlet.MultipartConfigElement;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.ServletRegistration.Dynamic;

import org.springframework.web.WebApplicationInitializer;

import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;

import org.springframework.web.servlet.DispatcherServlet;

/**

* 服务器启动入口类

*

* @author Administrator

*

*/

public class WebApplicationStartup implements WebApplicationInitializer {

private static final String SERVLET_NAME = Spring-mvc;

private static final long MAX_FILE_UPLOAD_SIZE = 1024 * 1024 * 5; // 5 Mb

private static final int FILE_SIZE_THRESHOLD = 1024 * 1024; // After 1Mb

private static final long MAX_REQUEST_SIZE = -1L; // No request size limit

/**

* 服务器启动调用此方法，在这里可以做配置作用与web.xml相同

*/

@Override

public void onStartup(ServletContext servletContext) throws ServletException {

// 注册springMvc的servlet

this.addServlet(servletContext);

// 注册过滤器

// servletContext.addFilter(arg0, arg1)

// 注册监听器

// servletContext.addListener(arg0);

}

/**

* 注册Spring servlet

*

* @param servletContext

*/

private void addServlet(ServletContext servletContext) {

// 构建一个application context

AnnotationConfigWebApplicationContext webContext = createWebContext(SpringMVC.class, ViewConfiguration.class);

// 注册spring mvc 的 servlet

Dynamic dynamic = servletContext.addServlet(SERVLET_NAME, new DispatcherServlet(webContext));

// 添加springMVC 允许访问的Controller后缀

dynamic.addMapping(*.html, *.ajax, *.css, *.js, *.gif, *.jpg, *.png);

// 全部通过请用 “/”

// dynamic.addMapping(/);

dynamic.setLoadOnStartup(1);

dynamic.setMultipartConfig(new MultipartConfigElement(null, MAX_FILE_UPLOAD_SIZE, MAX_REQUEST_SIZE, FILE_SIZE_THRESHOLD));

}

/**

* 通过自定义的配置类来实例化一个Web Application Context

*

* @param annotatedClasses

* @return

*/

private AnnotationConfigWebApplicationContext createWebContext(Class... annotatedClasses) {

AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext();

webContext.register(annotatedClasses);

return webContext;

}

}</code>

4.在com.easyweb.config 下添加类 SpringMVC 继承 WebMvcConfigurerAdapter，这个类的作用是进行SpringMVC的一些配置，代码如下：

<code class="hljs" java="">package com.easyweb.config;

import org.springframework.context.annotation.ComponentScan;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;

import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration

@EnableWebMvc

//指明controller所在的包名

@ComponentScan(basePackages = {com.easyweb.controller})

public class SpringMVC extends WebMvcConfigurerAdapter {

/**

* 非必须

*/

@Override

public void configureDefaultServletHandling(final DefaultServletHandlerConfigurer configurer) {

configurer.enable();

}

/**

* 如果项目的一些资源文件放在/WEB-INF/resources/下面

* 在浏览器访问的地址就是类似：https://host:port/projectName/WEB-INF/resources/xxx.css

* 但是加了如下定义之后就可以这样访问：

* https://host:port/projectName/resources/xxx.css

* 非必须

*/

@Override

public void addResourceHandlers(final ResourceHandlerRegistry registry) {

registry.addResourceHandler(/resources/**/*).addResourceLocations(/WEB-INF/resources/);

}

}</code>

5.添加view配置文件com.easyweb.config下新建类ViewConfiguration，里面可以根据自己的需要定义视图拦截器：

<code avrasm="" class="hljs">package com.easyweb.config;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.ViewResolver;

import org.springframework.web.servlet.view.JstlView;

import org.springframework.web.servlet.view.UrlBasedViewResolver;

import org.springframework.web.servlet.view.tiles2.TilesConfigurer;

import org.springframework.web.servlet.view.tiles2.TilesView;

@Configuration

public class ViewConfiguration {

@Bean

public ViewResolver urlBasedViewResolver() {

UrlBasedViewResolver viewResolver;

viewResolver = new UrlBasedViewResolver();

viewResolver.setOrder(2);

viewResolver.setPrefix(/WEB-INF/);

viewResolver.setSuffix(.jsp);

viewResolver.setViewClass(JstlView.class);

// for debug envirment

viewResolver.setCache(false);

return viewResolver;

}

@Bean

public ViewResolver tilesViewResolver() {

UrlBasedViewResolver urlBasedViewResolver = new UrlBasedViewResolver();

urlBasedViewResolver.setOrder(1);

urlBasedViewResolver.setViewClass(TilesView.class);

//urlBasedViewResolver.

return urlBasedViewResolver;

}

@Bean

public TilesConfigurer tilesConfigurer() {

TilesConfigurer tilesConfigurer = new TilesConfigurer();

tilesConfigurer.setDefinitions(new String[] { classpath:tiles.xml });

return tilesConfigurer;

}

}</code>

6.本例中还用了tiles视图解析器，替换了原始的include方式