18、springboot——嵌入式servlet容器修改+注册servlet三大组件

SpringBoot默认使用Tomcat作为嵌入式的Servlet容器

 1）、如何定制和修改Servlet容器的相关配置

        1、修改和server有关的配置

           （ServerProperties【也是EmbeddedServletContainerCustomizer】）

server.port=8088
server.servlet.context-path=/crud

//通用的Servlet容器设置
server.xxx

//Tomcat的设置
server.tomcat.xxx
server.tomcat.uri-encoding=UTF-8

　　 2、编写一个EmbeddedServletContainerCustomizer：

          　　  嵌入式的Servlet容器的定制器；来修改Servlet容器的配置

 

        　　 在Spring Boot2.0以上配置嵌入式Servlet容器时

         　　EmbeddedServletContainerCustomizer类不存在，

         　　经网络查询发现被WebServerFactoryCustomizer替代

@Configuration
public class MyServerConfig {

    //配置嵌入式的Servlet容器
    @Bean
    public WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> webServerFactoryCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>() {
            //定制嵌入式的Servlet容器相关的规则
            @Override
            public void customize(ConfigurableServletWebServerFactory factory) {
                factory.setPort(8083);
            }
        };
    }
    
}

 　　

2）、注册Servlet、Filter、Listener

　　由于SpringBoot默认是以jar包的方式启动嵌入式的Servlet容器来启动

　　SpringBoot的web应用，没有web.xml文件

 

　　使用一下三个类：

　　　　ServletRegistrationBean

　　　　FilterRegistrationBean

　　　　ServletListenerRegistrationBean

　　

　　1、注册Servlet

　　　　Servlet实现类：

public class MyServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       resp.getWriter().write("hello");
    }
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       doPost(req,resp);
    }
}

　　　　ServletRegistrationBean实现Servl加入容器

@Configuration
public class MyServerConfig {

    //注册三大组件
    //1、注册Servlet
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean<MyServlet> registrationBean = new ServletRegistrationBean<>();
        registrationBean.setServlet(new MyServlet());
        registrationBean.addUrlMappings("/myServlet");
        return registrationBean;
    }


    //配置嵌入式的Servlet容器
    @Bean
    public WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> webServerFactoryCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>() {
            //定制嵌入式的Servlet容器相关的规则
            @Override
            public void customize(ConfigurableServletWebServerFactory factory) {
                factory.setPort(8083);
            }
        };
    }
}

 　　 2、注册Filter

　　　　编写自定义的filter

public class MyFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("MyFilter...");
        filterChain.doFilter(servletRequest,servletResponse);
    }
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
    @Override
    public void destroy() {
    }
}

　　　　加入容器

@Configuration
public class MyServerConfig {

    //注册三大组件
    //1、注册Servlet
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean<MyServlet> registrationBean = new ServletRegistrationBean<>();
        registrationBean.setServlet(new MyServlet());
        registrationBean.addUrlMappings("/myServlet");
        return registrationBean;
    }

    //2、注册Filter
    @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new MyFilter());
        registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
        return  registrationBean;
    }

    //配置嵌入式的Servlet容器
    @Bean
    public WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> webServerFactoryCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>() {
            //定制嵌入式的Servlet容器相关的规则
            @Override
            public void customize(ConfigurableServletWebServerFactory factory) {
                factory.setPort(8083);
            }
        };
    }
}

　　　　再访问/myServlet的时候经过过滤器后控制台打印响应字符串

 　　3、注册Listener：

　　　　编写自定义Listener

public class MyListener implements ServletContextListener {
    //监听当前web项目销毁
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("web  end....");
    }
    //启动监听
    @Override
    public void contextInitialized(ServletContextEvent sce) {
 
        System.out.println("web  start...");
    }
}

　　　　加入容器

@Configuration
public class MyServerConfig {

    //注册三大组件
    //1、注册Servlet
    @Bean
    public ServletRegistrationBean myServlet(){
        ServletRegistrationBean<MyServlet> registrationBean = new ServletRegistrationBean<>();
        registrationBean.setServlet(new MyServlet());
        registrationBean.addUrlMappings("/myServlet");
        return registrationBean;
    }

    //2、注册Filter
    @Bean
    public FilterRegistrationBean myFilter(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new MyFilter());
        registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
        return  registrationBean;
    }
    
    //3、注册Listener
    @Bean
    public ServletListenerRegistrationBean servletListenerRegistrationBean(){
        ServletListenerRegistrationBean registrationBean = new ServletListenerRegistrationBean();
        registrationBean.setListener(new MyListener());
        return registrationBean;
    }
    
    //配置嵌入式的Servlet容器
    @Bean
    public WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> webServerFactoryCustomizer(){
        return new WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>() {
            //定制嵌入式的Servlet容器相关的规则
            @Override
            public void customize(ConfigurableServletWebServerFactory factory) {
                factory.setPort(8083);
            }
        };
    }
    
}

 同时可以设置的参数很多如load-starton......

SpringBoot帮我们自动SpringMVC的时候，自动的注册SpringMVC的前端控制器；

DIspatcherServlet；DispatcherServletAutoConfiguration中：

@Bean(
    name = {"dispatcherServletRegistration"}
)
@ConditionalOnBean(
    value = {DispatcherServlet.class},
    name = {"dispatcherServlet"}
)
public DispatcherServletRegistrationBean dispatcherServletRegistration(DispatcherServlet dispatcherServlet) {
    DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(dispatcherServlet, this.webMvcProperties.getServlet().getPath());
//默认拦截： / 所有请求；包静态资源，但是不拦截jsp请求
//   /*会拦截jsp
//可以通过server.servletPath来修改SpringMVC前端控制器默认拦截的请求路径

 registration.setName("dispatcherServlet");
    registration.setLoadOnStartup(this.webMvcProperties.getServlet().getLoadOnStartup());
    if (this.multipartConfig != null) {
        registration.setMultipartConfig(this.multipartConfig);
    }

    return registration;
}

 getPath->WebMvcProperties ->  private String path = "/";