SpringBoot配置嵌入式Servlet容器和使用外置Servlet容器的教程图解

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SpringBoot配置嵌入式Servlet容器和使用外置Servlet容器的教程图解

配置嵌入式Servlet容器

SpringBoot默认使用Tomcat作为嵌入式的Servlet容器;

问题?

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=8081

server.context-path=/crud

server.tomcat.uri-encoding=UTF-8

//通用的Servlet容器设置

server.xxx

//Tomcat的设置

server.tomcat.xxx

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(1.x)

在Spring Boot2.0以上配置嵌入式Servlet容器时EmbeddedServletContainerCustomizer类不存在,被WebServerFactoryCustomizer替代。

1.x

@Bean //一定要将这个定制器加入到容器中

public EmbeddedServletContainerCustomizer embeddedServletContainerCustomizer(){

return new WebServerFactoryCustomizer {

//定制嵌入式的Servlet容器相关的规则

@Override

public void customize(ConfigurableWebServerFactory factory) {

container.setPort(8083);

}

};

}

2.x

@Bean //一定要将这个定制器加入到容器中

public EmbeddedServletContainerCustomizer embeddedServletContainerCustomizer(){

return new EmbeddedServletContainerCustomizer() {

//定制嵌入式的Servlet容器相关的规则

@Override

public void customize(ConfigurableEmbeddedServletContainer container) {

container.setPort(8083);

}

};

}

2)、注册Servlet三大组件【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。

注册三大组件用以下方式

ServletRegistrationBean

//注册三大组件

@Bean

public ServletRegistrationBean myServlet(){

ServletRegistrationBean registrationBean = new ServletRegistrationBean(new MyServlet(),"/myServlet");

return registrationBean;

}

FilterRegistrationBean

@Bean

public FilterRegistrationBean myFilter(){

FilterRegistrationBean registrationBean = new FilterRegistrationBean();

registrationBean.setFilter(new MyFilter());

registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));

return registrationBean;

}

ServletListenerRegistrationBean

@Bean

public ServletListenerRegistrationBean myListener(){

ServletListenerRegistrationBean registrationBean = new ServletListenerRegistrationBean<>(new MyListener());

return registrationBean;

}

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 = 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(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);

registration.setLoadOnStartup(

this.webMvcProperties.getServlet().getLoadOnStartup());

if (this.multipartConfig != null) {

registration.setMultipartConfig(this.multipartConfig);

}

return registration;

}

2)、SpringBoot能不能支持其他的Servlet容器;

3)、替换为其他嵌入式Servlet容器

默认支持:

Tomcat(默认使用)

org.springframework.boot

spring-boot-starter-web

引入web模块默认就是使用嵌入式的Tomcat作为Servlet容器;

Jetty

org.springframework.boot

spring-boot-starter-web

spring-boot-starter-tomcat

org.springframework.boot

spring-boot-starter-jetty

ohttp://rg.springframework.boot

Undertow

org.springframework.boot

spring-boot-starter-web

spring-boot-starter-tomcat

org.springframework.boot

spring-boot-starter-undertow

org.springframework.boot

4)、嵌入式Servlet容器自动配置原理;

SpringBoot2.X原理略有不同

由EmbeddedWebServerFactoryCustomizerAutoConfiguration(嵌入式web服务工厂定制器自动配置类)而不是EmbeddedServletContainerAutoConfiguration(嵌入式的Servlet容器自动配置),根据导入的依赖信息,该配置类会自动创建相应类型的容器工厂定制器(目前Spring Boot 2.x 版本支持tomcat、jetty、undertow、netty),以tomcat为例,这里会创建TomcatWebServerFactoryCustomizer组件:

@Configuration(proxyBeanMethods = false)

@ConditionalOnWebApplication

//指定类ServerProperties(Servlet容器相关的配置类)中的ConfigurationProperties功能,将配置文件中对应的属性值与配置类中的属性值进行映射,并将该配置类添加到IOC容器中

@EnableConfigurationProperties(ServerProperties.class)

public class EmbeddedWebServerFactoryCustomizerAutoConfiguration {

/**

* Nested configuration if Tomcat is being used.

*/

@Configuration(proxyBeanMethods = false)

//导入的Servlet依赖为Tomcat,则创建Tomcat web服务工厂定制器

@ConditionalOnClass({ Tomcat.class, UpgradeProtocol.class })

public static class TomcatWebServerFactoryCustomizerConfiguration {

@Bean

public TomcatWebServerFactoryCustomizer tomcatWebServerFactoryCustomizer(Environment environment,ServerProperties serverProperties) {

return new TomcatWebServerFactoryCustomizer(environment, serverProperties);

}

}

...

}

1.X中通过EmbeddedServletContainerAutoConfiguration:嵌入式的Servlet容器自动配置类创建组件

@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)

@Configuration

@ConditionalOnWebApplication

@Import(BeanPostProcessorsRegistrar.class)

//导入BeanPostProcessorsRegistrar:Spring注解版;给容器中导入一些组件

//导入了EmbeddedServletContainerCustomizerBeanPostProcessor:

//后置处理器:bean初始化前后(创建完对象,还没赋值赋值)执行初始化工作

public class EmbeddedServletContainerAhttp://utoConfiguration {

@Configuration

@ConditionalOnClass({ Servlet.class, Tomcat.class })//判断当前是否引入了Tomcat依赖;

@ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)//判断当前容器没有用户自己定义EmbeddedServletContainerFactory:嵌入式的Servlet容器工厂;作用:创建嵌入式的Servlet容器

public static class EmbeddedTomcat {

@Bean

public TomcatEmbeddedServletContainerFactory tomcatEmbeddedServletContainerFactory() {

return new TomcatEmbeddedServletContainerFactory();

}

}

/**

* Nested configuration if Jetty is being used.

*/

@Configuration

@ConditionalOnClass({ Servlet.class, Server.class, Loader.class,

WebAppContext.class })

@ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)

public static class EmbeddedJetty {

@Bean

public JettyEmbeddedServletContainerFactory jettyEmbeddedServletContainerFactory() {

return new JettyEmbeddedServletContainerFactory();

}

}

/**

* Nested configuration if Undertow is being used.

*/

@Configuration

@ConditionalOnClass({ Servlet.class, Undertow.class, SslClientAuthMode.class })

@ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)

public static class EmbeddedUndertow {

@Bean

public UndertowEmbeddedServletContainerFactory undertowEmbeddedServletContainerFactory() {

return new UndertowEmbeddedServletContainerFactory();

}

}

1)、EmbeddedServletContainerFactory(嵌入式Servlet容器工厂)

public interface EmbeddedServletContainerFactory {

//获取嵌入式的Servlet容器

EmbeddedServletContainer getEmbeddedServletContainer(

ServletContextInitializer... initializers);

}

2)、EmbeddedServletContainer:(嵌入式的Servlet容器)

3)、以TomcatEmbeddedServletContainerFactory为例

@Override

public EmbeddedServletContainer getEmbeddedServletContainer(

ServletContextInitializer... initializers) {

//创建一个Tomcat

Tomcat tomcat = new Tomcat();

//配置Tomcat的基本环节

File baseDir = (this.baseDirectory != null ? this.baseDirectory

: createTempDir("tomcat"));

tomcat.setBaseDir(baseDir.getAbsolutePath());

Connector connector = new Connector(this.protocol);

tomcat.getService().addConnector(connector);

customizeConnector(connector);

tomcat.setConnector(connector);

tomcat.getHost().setAutoDeploy(false);

configureEngine(tomcat.getEngine());

for (Connector additionalConnector : this.additionalTomcatConnectors) {

tomcat.getService().addConnector(additionalConnector);

}

prepareContext(tomcat.getHost(), initializers);

//将配置好的Tomcat传入进去,返回一个EmbeddedServletContainer;并且启动Tomcat服务器

return getTomcatEmbeddedServletContainer(tomcat);

}

4)、我们对嵌入式容器的配置修改是怎么生效?

ServerProperties、EmbeddedServletContainerCustomizer

EmbeddedServletContainerCustomizer:定制器帮我们修改了Servlet容器的配置?

怎么修改的原理?

5)、容器中导入了EmbeddedServletContainerCustomizerBeanPostProcessor

//初始化之前

@Override

public Object postProcessBeforeInitialization(Object bean, String beanName)

throws BeansException {

//如果当前初始化的是一个ConfigurableEmbeddedServletContainer类型的组件

if (bean instanceof ConfigurableEmbeddedServletContainer) {

//

postProcessBeforeInitialization((ConfigurableEmbeddedServletContainer) bean);

}

return bean;

}

private void postProcessBeforeInitialization(

ConfigurableEmbeddedServletContainer bean) {

//获取所有的定制器,调用每一个定制器的customize方法来给Servlet容器进行属性赋值;

for (EmbeddedServletContainerCustomizer customizer : getCustomizers()) {

customizer.customize(bean);

}

}

private Collection getCustomizers() {

if (this.customizers == null) {

// Look up does not include the parent context

this.customizers = new ArrayList(

this.beanFactory

//从容器中获取所有这葛类型的组件:EmbeddedServletContainerCustomizer

//定制Servlet容器,给容器中可以添加一个EmbeddedServletContainerCustomizer类型的组件

.getBeansOfType(EmbeddedServletContainerCustomizer.class,

false, false)

.values());

Collections.sort(this.customizers, AnnotationAwareOrderComparator.INSTANCE);

this.customizers = Collections.unmodifiableList(this.customizers);

}

return this.customizers;

}

ServerProperties也是定制器

步骤:

1)、SpringBoot根据导入的依赖情况,给容器中添加相应的EmbeddedServletContainerFactory【TomcatEmbeddedServletContainerFactory】

2)、容器中某个组件要创建对象就会惊动后置处理器;EmbeddedServletContainerCustomizerBeanPostProcessor;

只要是嵌入式的Servlet容器工厂,后置处理器就工作;

3)、后置处理器,从容器中获取所有的EmbeddedServletContainerCustomizer,调用定制器的定制方法

5)、嵌入式Servlet容器启动原理;

什么时候创建嵌入式的Servlet容器工厂?什么时候获取嵌入式的Servlet容器并启动Tomcat;

获取嵌入式的Servlet容器工厂:

1)、SpringBoot应用启动运行run方法

2)、refreshContext(context);SpringBoot刷新IOC容器【创建IOC容器对象,并初始化容器,创建容器中的每一个组件】;如果是web应用创建AnnotationConfigEmbeddedWebApplicationContext,否则:AnnotationConfigApplicationContext

3)、refresh(context);刷新刚才创建好的ioc容器;

public void refresh() throws BeansException, IllegalStateException {

synchronized (this.startupShutdownMonitor) {

// Prepare this context for refreshing.

prepareRefresh();

// Tell the subclass to refresh the internal bean factory.

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

// Prepare the bean factory for use in this context.

prepareBeanFactory(beanFactory);

try {

// Allows post-processing of the bean factory in context subclasses.

postProcessBeanFactory(beanFactory);

// Invoke factory processors registered as beans in the context.

invokeBeanFactoryPostProcessors(beanFactory);

// Register bean processors that intercept bean creation.

regishttp://terBeanPostProcessors(beanFactory);

// Initialize message source for this context.

initMessageSource();

// Initialize event multicaster for this context.

initApplicationEventMulticaster();

// Initialize other special beans in specific context subclasses.

onRefresh();

// Check for listener beans and register them.

registerListeners();

// Instantiate all remaining (non-lazy-init) singletons.

finishBeanFactoryInitialization(beanFactory);

// Last step: publish corresponding event.

finishRefresh();

}

catch (BeansException ex) {

if (logger.isWarnEnabled()) {

logger.warn("Exception encountered during context initialization - " +

"cancelling refresh attempt: " + ex);

}

// Destroy already created singletons to avoid dangling resources.

destroyBeans();

// Reset 'active' flag.

cancelRefresh(ex);

// Propagate exception to caller.

throw ex;

}

finally {

// Reset common introspection caches in Spring's core, since we

// might not ever need metadata for singleton beans anymore...

resetCommonCaches();

}

}

}

4)、 onRefresh(); web的ioc容器重写了onRefresh方法

5)、webioc容器会创建嵌入式的Servlet容器;createEmbeddedServletContainer();

6)、获取嵌入式的Servlet容器工厂:

EmbeddedServletContainerFactory containerFactory = getEmbeddedServletContainerFactory();

​从ioc容器中获取EmbeddedServletContainerFactory 组件;TomcatEmbeddedServletContainerFactory创建对象,后置处理器一看是这个对象,就获取所有的定制器来先定制Servlet容器的相关配置;

7)、使用容器工厂获取嵌入式的Servlet容器:this.embeddedServletContainer = containerFactory .getEmbeddedServletContainer(getSelfInitializer());

8)、嵌入式的Servlet容器创建对象并启动Servlet容器;

先启动嵌入式的Servlet容器,再将ioc容器中剩下没有创建出的对象获取出来;

IOC容器启动创建嵌入式的Servlet容器

使用外置的Servlet容器

嵌入式Servlet容器:应用打成可执行的jar

​优点:简单、便携;

​缺点:默认不支持JSP、优化定制比较复杂(使用定制器【ServerProperties、自定义EmbeddedServletContainerCustomizer】,自己编写嵌入式Servlet容器的创建工厂【EmbeddedServletContainerFactory】);

外置的Servlet容器:外面安装Tomcat---应用war包的方式打包;

步骤

1)、必须创建一个war项目;(利用idea创建好目录结构)

2)、将嵌入式的Tomcat指定为provided;

org.springframework.boot

spring-boot-starter-tomcat

provided

3)、必须编写一个SpringBootServletInitializer的子类,并调用configure方法

public class ServletInitializer extends SpringBootServletInitializer {

@Override

protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {

//传入SpringBoot应用的主程序

return application.sources(SpringBoot04WebJspApplication.class);

}

}

4)、启动服务器就可以使用;

原理

jar包:执行SpringBoot主类的main方法,启动ioc容器,创建嵌入式的Servlet容器;

war包:启动服务器,服务器启动SpringBoot应用【SpringBootServletInitializer】,启动ioc容器;

servlet3.0(Spring注解版):

8.2.4 Shared libraries / runtimes pluggability:

规则:

​1)、服务器启动(web应用启动)会创建当前web应用里面每一个jar包里面ServletContainerInitializer实例:

​2)、ServletContainerInitializer的实现放在jar包的META-INF/services文件夹下,有一个名为javax.servlet.ServletContainerInitializer的文件,内容就是ServletContainerInitializer的实现类的全类名

​3)、还可以使用@HandlesTypes,在应用启动的时候加载我们感兴趣的类;

流程:

1)、启动Tomcat

2)、org\springframework\spring-web\4.3.14.RELEASE\spring-web-4.3.14.RELEASE.jar!\META-INF\services\javax.servlet.ServletContainerInitializer:

Spring的web模块里面有这个文件:org.springframework.web.SpringServletContainerInitializer

3)、SpringServletContainerInitializer将@HandlesTypes(WebApplicationInitializer.class)标注的所有这个类型的类都传入到onStartup方法的Set>;为这些WebApplicationInitializer类型的类创建实例;

4)、每一个WebApplicationInitializer都调用自己的onStartup;

5)、相当于我们的SpringBootServletInitializer的类会被创建对象,并执行onStartup方法

6)、SpringBootServletInitializer实例执行onStartup的时候会createRootApplicationContext;创建容器

protected WebApplicationContext createRootApplicationContext(

ServletContext servletContext) {

//1、创建SpringApplicationBuilder

SpringApplicationBuilder builder = createSpringApplicationBuilder();

StandardServletEnvironment environment = new StandardServletEnvironment();

environment.initPropertySources(servletContext, null);

builder.environment(environment);

builder.main(getClass());

ApplicationContext parent = getExistingRootWebApplicationContext(servletContext);

if (parent != null) {

this.logger.info("Root context already created (using as parent).");

servletContext.setAttribute(

WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, null);

builder.initializers(new ParentContextApplicationContextInitializer(parent));

}

builder.initializers(

new ServletContextApplicationContextInitializer(servletContext));

builder.contextClass(AnnotationConfigEmbeddedWebApplicationContext.class);

//调用configure方法,子类重写了这个方法,将SpringBoot的主程序类传入了进来

builder = configure(builder);

//使用builder创建一个Spring应用

SpringApplication application = builder.build();

if (application.getSources().isEmpty() && AnnotationUtils

.findAnnotation(getClass(), Configuration.class) != null) {

application.getSources().add(getClass());

}

Assert.state(!application.getSources().isEmpty(),

"No SpringApplication sources have been defined. Either override the "

+ "configure method or add an @Configuration annotation");

// Ensure error pages are registered

if (this.registerErrorPageFilter) {

application.getSources().add(ErrorPageFilterConfiguration.class);

}

//启动Spring应用

return run(application);

}

7)、Spring的应用就启动并且创建IOC容器

public ConfigurableApplicationContext run(String... args) {

StopWatch stopWatch = new StopWatch();

stopWatch.start();

ConfigurableApplicationContext context = null;

FailureAnalyzers analyzers = null;

configureHeadlessProperty();

SpringApplicationRunListeners listeners = getRunListeners(args);

listeners.starting();

try {

ApplicationArguments applicationArguments = new DefaultApplicationArguments(

args);

ConfigurableEnvironment environment = prepareEnvironment(listeners,

applicationArguments);

Banner printedBanner = printBanner(environment);

context = createApplicationContext();

analyzers = new FailureAnalyzers(context);

prepareContext(context, environment, listeners, applicationArguments,

printedBanner);

//刷新IOC容器

refreshContext(context);

afterRefresh(context, applicationArguments);

listeners.finished(context, null);

stopWatch.stop();

if (this.logStartupInfo) {

new StartupInfoLogger(this.mainApplicationClass)

.logStarted(getApplicationLog(), stopWatch);

}

return context;

}

catch (Throwable ex) {

handleRunFailure(context, listeners, analyzers, ex);

throw new IllegalStateException(ex);

}

}

启动Servlet容器,再启动SpringBoot应用


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