spring boot配置Servlet容器

Spring boot 默认使用Tomcat作为嵌入式Servlet容器,只需要引入spring-boot-start-web依赖,默认采用的Tomcat作为容器

01  定制和修改Servlet容器的相关配置(ServerProperties是EmbeddedServletContainerCustomizer的子类)

server.port=8080
server.context-path=/  

# tomcat相关设置
server.tomcat.uri-encoding=UTF-8  

也可以编写EmbeddedServletContainerCustomizer(嵌入式的Servlet容器定制器),来修改servlet容器的配置

@Bean
public EmbeddedServletContainerCustomizer embeddedServletContainerCustomizer(){
    //定制嵌入式的Servlet容器相关的属性配置
    return container -> container.setPort(8083);
} 

2 注册Servlet容器的三大组件(Servlet  Filter  Listener)

spring boot默认采用是以jar包的形式启动嵌入式的servlet容器,从而启动Springboot的web应用,没有web.xml,当然也可以使用注解的方式(@WebServlet,@WebListener,@WebFilter),现在使用Spring boot作为框架,如果编写三大组件,则需要使用配置的方式进行注册

01 ServletRegistrationBean:注册Servlet

//Servlet定义
public class MyServlet extends HttpServlet {  

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("这是一个servlet请求...");
    }
}  

//Servlet注册
@Configuration
public class MyServletConfig {  

    //注册Servlet
    @Bean
    public ServletRegistrationBean myServlet(){
        return new ServletRegistrationBean(new MyServlet(), "/myServlet");
    }
} 

02 FilterRegistrationBean:注册Filter

//Filter定义
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {  

    }  

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.out.println("MyFilter process...");
        //放行
        chain.doFilter(request, response);
    }  

    @Override
    public void destroy() {  

    }
}  

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

ServletListenerRegistrationBean:注册Listener

//Listener定义
public class MyListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        System.out.println("contextInitialized...web启动");
    }  

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        System.out.println("contextDestroyed...web销毁");
    }
}  

//Listener注册
@Bean
public ServletListenerRegistrationBean myListener(){
    return new ServletListenerRegistrationBean<>(new MyListener());
} 

最熟悉的是,spring boot 在自动配置springMVC,会自动注册SpringMVC前端控制器:DispatcherServlet,该控制器主要在DispatcherServletAutoConfiguration自动配置类中进行注册

@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Configuration
@ConditionalOnWebApplication
@ConditionalOnClass(DispatcherServlet.class)
@AutoConfigureAfter(EmbeddedServletContainerAutoConfiguration.class)
public class DispatcherServletAutoConfiguration {  

    //other code...  

    public static final String DEFAULT_DISPATCHER_SERVLET_BEAN_NAME = "dispatcherServlet";  

    private String servletPath = "/";  

    @Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
                @ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
    public ServletRegistrationBean dispatcherServletRegistration(
        DispatcherServlet dispatcherServlet) {
        ServletRegistrationBean registration = new ServletRegistrationBean(
            dispatcherServlet, this.serverProperties.getServletMapping());
        //默认拦截 / 所有请求，包括静态资源，但是不拦截jsp请求；/*会拦截jsp
        //可以通过修改server.servlet-path来修改默认的拦截请求
        registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
        registration.setLoadOnStartup(
            this.webMvcProperties.getServlet().getLoadOnStartup());
        if (this.multipartConfig != null) {
            registration.setMultipartConfig(this.multipartConfig);
        }
        return registration;
    }
}  

3 其他Servlet容器

Spring boot默认支持Tomcat,Jetty 和Undertow作为底层容器

而Spring boot默认使用Tomcat,一旦引入spring-boot-starter-web模块,就默认使用Tomcat

切换其其他Servlet容器

将tomcat依赖移除同事引入其他Servlet容易

引入jetty

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <groupId>org.springframework.boot</groupId>
        </exclusion>
    </exclusions>
</dependency>  

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jetty</artifactId>
</dependency> 

引入undertow

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <groupId>org.springframework.boot</groupId>
        </exclusion>
    </exclusions>
</dependency>  

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jetty</artifactId>
</dependency> 

参考文章   https://blog.csdn.net/caychen/article/details/80344372

这里对于常见的容器jetty和tomcat做一个简单对比

jetty  更轻量级,更加灵活,可插拔和可扩展,其架构是基于Handler来实现的,可以同时处理大量长时间连接,默认采用NIO,在处理静态资源性能较高

Tomcat  默认采用BIO,基于容器设计的,不易扩展,对JavaEE和Servlet的支持更加全面,很多特性直接集成