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基于JavaConfig配置的Spring MVC的构建

上一篇讲了基于XML配置的构建,这一篇讲一讲基于JavaConfig的构建。为什么要写这篇文章,因为基于xml配置的构建,本人认为很麻烦,要写一堆的配置,不够简洁,而基于JavacConfig配置的构建符合程序员的编码习惯,是SpringMVC以后的趋势。不是说基于XML配置的不好,毕竟现在很多已有的项目都是基于XML的,只是基于JavaConfig配置的更优化,而且两种方式可以鱼和熊掌兼得。但要知道的是,基于JavaConfig配置构建的Spring MVC项目只能部署到支持Servlet 3.0服务器上面。

进入正题,开始搭建项目:

搭建环境:

1. IDEA

2. Maven

3. Tomcat

搭建步骤:

1. 创建maven-archetype-webapp项目,这个项目是maven的web项目

2.在pom中添加sping mvc相关的依赖包,这个依赖包是我自己使用的,包含了单元测试和相关的mvc mock包:

<dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.3.9.RELEASE</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/javax.servlet.jsp.jstl-api -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-jpa</artifactId>
      <version>1.10.1.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.0.1</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>4.3.8.RELEASE</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>javax.servlet.jsp-api</artifactId>
      <version>2.3.1</version>
    </dependency>

    <dependency>
      <groupId>org.mockito</groupId>
      <artifactId>mockito-core</artifactId>
      <version>2.8.47</version>
    </dependency>

  </dependencies>

3.将DispatcherSevlet配置在Servlet容器中

public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    /*加载后端的中间层和数据层组件*/
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[]{RootConfig.class};
    }

    /*加载web组件,控制器、试图解析器、处理器映射*/
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[]{WebConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

示例代码中要知道的是,任何扩展了AbstractAnnotationConfigDispatcherServletInitializer的类都会自动配置DispatcherServlet和Spring应用上下文。实际上,AbstractAnnotationConfigDispatcherServletInitializer会同时创建DispatcherServlet和ContextLoaderListener。getServletConfigClasses()方法返回的带有@Configuration注解的类会用来定义DispatcherServlet应用上下文中的bean。getRootConfigClasses()方法返回的带有@Configuration注解的类会用来定义ContextLoaderListener应用上下文中的bean。

4.创建WebConfig类

@Configuration
@EnableWebMvc
@ComponentScan("spittr.web")
public class WebConfig extends WebMvcConfigurerAdapter {

    /*配置视图解析器*/
    @Bean
    public ViewResolver viewResolver(){
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        resolver.setExposeContextBeansAsAttributes(true);
        return  resolver;
    }


    /*配置静态资源的处理*/
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
}

5.创建RootConfig类

@Configuration
@ComponentScan(basePackages = {"spittr"},excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,value = http://www.mamicode.com/EnableWebMvc.class)})>

6,到这里配置已经结束。怎样创建Controller和运行请参考上一篇基于XML配置的Spring MVC。

7.最后附上源码:源码

基于JavaConfig配置的Spring MVC的构建