springMVC-搭建springMVC环境-Java方式

男娘i 2024-04-17 05:59 34阅读 0赞

**SpringMVC请求处理流程**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L211c2lfbQ_size_16_color_FFFFFF_t_70]  
1 添加相关依赖

<dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.11</version>
          <scope>test</scope>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>${spring.version}</version>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-core</artifactId>
          <version>${spring.version}</version>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-beans</artifactId>
          <version>${spring.version}</version>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context-support</artifactId>
          <version>${spring.version}</version>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-expression</artifactId>
          <version>${spring.version}</version>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-test</artifactId>
          <version>${spring.version}</version>
        </dependency>
    
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-web</artifactId>
          <version>${spring.version}</version>
        </dependency>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-webmvc</artifactId>
          <version>4.3.17.RELEASE</version>
        </dependency>
        <dependency>
          <groupId>javax.servlet</groupId>
          <artifactId>javax.servlet-api</artifactId>
          <version>3.1.0</version>
        </dependency>

2 使用Java方式搭建SpringMVC  
1)配置DispatcherServlet

package com.musi;
    
    import com.musi.config.RootConfig;
    import com.musi.config.WebConfig;
    import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
    
    /**
     * @Author:musi
     * @Date:2019/8/18
     * @Description:
     */
    public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    
        @Override
        protected Class<?>[] getRootConfigClasses() {
            return new Class<?>[]{RootConfig.class};
        }
    
        @Override
        protected Class<?>[] getServletConfigClasses() {
            return new Class<?>[]{WebConfig.class};
        }
    
        @Override
        protected String[] getServletMappings() {
            return new String[]{"/"};
        }
    }

AbstractAnnotationConfigDispatcherServletInitializer剖析  
在Servlet3.0环境中,容器会在类路径下查找实现javax.servlet.ServletContainerInitializer接口的类,如果能发现的话,就会用它来配置Servlert容器.Spring提供了这个接口的实现，名为SpringServletContainerInitializer，这个类反过来又会查找实现WebApplicationInitializer的类并将配置的任务交给它们来完成。Spring3.2引入了一个便利的WebApplicationInitializer基础实现，也就是AbstractAnnotationConfigDispatcherServletInitializer。程序中SpittrWebAppInitializer 扩展了AbstractAnnotationConfigDispatcherServletInitializer,因此当部署到Servlet3.0容器中的时候,容器会自动发现它,并用它类配置Servlet上下文  
三个方法的解析:  
getServletMappings();将一个或多个路径映射到DispatcherServlet上,本例中映射的是"/",这表示它会是应用的默认Servlet,它会处理应用的所有请求  
当DispatcherServlet启动的时候，它会创建Spring应用上下文，并加载配置文件或配置类中所声明的bean。在上面程序的getServletConfigClasses()方法中，我们要求DispatcherServlet加载应用上下文时，使用定义在WebConfig配置类（使用Java配置）中的bean。但是在SpringWeb应用中，通常还会有另外一个应用上下文。另外的这个应用上下文是由ContextLoaderListener创建的。我们希望DispatcherServlet加载包含Web组件的bean，如控制器、视图解析器以及处理器映射，而ContextLoaderListener要加载应用中的其他bean。这些bean通常是驱动应用后端的中间层和数据层组件。实际上，AbstractAnnotationConfigDispatcherServletInitializer会同时创建DispatcherServlet和ContextLoaderListener。GetServletConfigClasses()方法返回的带有@Configuration注解的类将会用来定义DispatcherServlet应用上下文中的bean。getRootConfigClasses()方法返回的带有@Configuration注解的类将会用来配置ContextLoaderListener创建的应用上下文中的bean。

注意:通过AbstractAnnotationConfigDispatcherServlet-Initializer来配置DispatcherServlet是传统web.xml方式的替代方案。如果你愿意的话，可以同时包含web.xml和AbstractAnnotationConfigDispatcher-ServletInitializer，但这其实并没有必要。如果按照这种方式配置DispatcherServlet，问题在于它只能部署到支持Servlet3.0的服务器中才能正常工作，如Tomcat7或更高版本。

2)配置WebConfig

/**
     * @Author:musi
     * @Date:2019/8/18
     * @Description:
     */
    @Configuration
    @EnableWebMvc
    @ComponentScan("com.musi")
    public class WebConfig extends WebMvcConfigurerAdapter{
    
        @Bean
        public ViewResolver viewResolver(){
            InternalResourceViewResolver resolver = new InternalResourceViewResolver();
            resolver.setPrefix("/WEB-INF/views/");
            resolver.setSuffix(".jsp");
            resolver.setExposeContextBeansAsAttributes(true);
            return resolver;
        }
    
        @Override
        public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer){
            configurer.enable();
        }
    
    }

3)配置rootconfig

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;
    
    /**
     * @Author:musi
     * @Date:2019/8/18
     * @Description:
     */
    @Configuration
    @ComponentScan(basePackages = {"com.musi"},excludeFilters = {@ComponentScan.Filter(type = FilterType.ANNOTATION,value = EnableWebMvc.class)})
    public class RootConfig {
    }

1.  编辑controller

import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    
    /**
     * @Author:musi
     * @Date:2019/8/25
     * @Description:
     */
    @Controller
    public class HomeController {
    
        @RequestMapping(value="/",method = RequestMethod.GET)
        public String home(){
            return "home";
        }
    
    
    }

5)编辑home页

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L211c2lfbQ_size_16_color_FFFFFF_t_70 1]  
6)测试控制器

/**
     * @Author:musi
     * @Date:2019/8/25
     * @Description:
     */
    public class HomeControllerTest {
    
        @Test
        public void testHomePage(){
            HomeController controller = new HomeController();
            Assert.assertEquals("home",controller.home());
        }
    
        @Test
        public void testHome() throws Exception {
            HomeController controller = new HomeController();
            MockMvc mockMvc = standaloneSetup(controller).build();
            mockMvc.perform(get("/")).andExpect(view().name("home"));
    
        }
    
    }

7)自定义DispatcherServlet配置  
配置springMVC时,除了实现AbstractAnnotationConfigDispatcherServletInitializer必须的三个抽象方法外,还可以有更多的方法可以重载.其中之一便是customizeRegistration().通过重载customizeRegistration()方法,我们可以对DispatcherServlet进行额外的配置.  
如下所示:

@Override
    protected  void customizeRegistration(Dynamic registration){
        registration.setMultipartConfig(new MultipartConfigElement("/tmp/spittr/uploads")); //设置对multipart的支持,将上传文件的临时目录设置为"tmp/spittr/uploads"
    }

8)添加其他servlet和filter

import com.musi.filter.MyFilter;
    import com.musi.servlet.MyServlet;
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.web.WebApplicationInitializer;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterRegistration;
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRegistration;
    
    /**
     * @Author:musi
     * @Date:2019/8/25
     * @Description:
     */
    public class MyServletInitializer implements WebApplicationInitializer {
    
        /***
         * 注册servlet
         * @param servletContext
         * @throws ServletException
         */
        /*@Override
        public void onStartup(ServletContext servletContext) throws ServletException {
            ServletRegistration.Dynamic myservlet = servletContext.addServlet("myServlet", MyServlet.class);
            myservlet.addMapping("/custom*//**");
        }*/
    
        /**
         * 注册过滤器
         * @param servletContext
         * @throws ServletException
         */
        @Override
        public void onStartup(ServletContext servletContext) throws ServletException {
            // 注册过滤器
            FilterRegistration.Dynamic filter = servletContext.addFilter("myFilter", MyFilter.class);
            filter.addMappingForUrlPatterns(null,false,"custom/**");
    
            // 注册servlet
            ServletRegistration.Dynamic myservlet = servletContext.addServlet("myServlet", MyServlet.class);
            myservlet.addMapping("/custom/**");
    
        }

备注:如果只是注册Filter,并且该Filter只会映射到DispatcherServlet上,那么还有一种快捷的方式,如下:  
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L211c2lfbQ_size_16_color_FFFFFF_t_70 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/16/13a4fa5f472e468a8d86f5e13c7f3e22.png
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