SpringBoot_配置嵌入式Servlet容器
SpringBoot_配置嵌入式Servlet容器
SpringBoot默认使用Tomcat作为嵌入式的Servlet容器
一、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】
//org.springframework.boot.autoconfigure.web.ServerProperties
@ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
public class ServerProperties
implements EmbeddedServletContainerCustomizer, EnvironmentAware, Ordered {
/**
* Server HTTP port.
*/
private Integer port;
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 EmbeddedServletContainerCustomizer
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
@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);
}
};
}
二、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
a)方式一
ServletRegistrationBean
//注册三大组件
@Bean
public ServletRegistrationBean myServlet(){
ServletRegistrationBean registrationBean = new ServletRegistrationBean(new MyServlet(),"/myServlet");
return registrationBean;
}
public class MyServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException {
response.getWriter().write("Hello,MyServlet");
}
}
FilterRegistrationBean
@Bean
public FilterRegistrationBean myFilter(){
FilterRegistrationBean registrationBean = new FilterRegistrationBean();
registrationBean.setFilter(new MyFilter());
registrationBean.setUrlPatterns(Arrays.asList("/hello","/myServlet"));
return registrationBean;
}
public class MyFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException { }
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
System.out.println("MyFilter process...");
filterChain.doFilter(request, response);
}
@Override
public void destroy() { }
}
ServletListenerRegistrationBean
@Bean
public ServletListenerRegistrationBean myListener(){
ServletListenerRegistrationBean<MyListener> registrationBean = new ServletListenerRegistrationBean<>(new MyListener());
return registrationBean;
}
public class MyListener implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent servletContextEvent) {
System.out.println("contextInitialized...web应用启动");
}
@Override
public void contextDestroyed(ServletContextEvent servletContextEvent) {
System.out.println("contextDestroyed...当我web项目销毁");
}
}
b)使用注解
@WebServlet(urlPatterns = "/my/servlet",asyncSupported = true)
public class MyServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//response.getWriter().print("Hello,world");
AsyncContext asyncContext = request.startAsync();
asyncContext.start(()->{
try {
response.getWriter().print("Hello,world");
//触发完成
asyncContext.complete();
} catch (IOException e) {
e.printStackTrace();
}
});
}
}
三、自动的注册SpringMVC的前端控制器
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:
//org.springframework.boot.autoconfigure.web.DispatcherServletAutoConfiguration.DispatcherServletRegistrationConfiguration#dispatcherServletRegistration
@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;
}
四、替换为其他嵌入式Servlet容器
a)默认支持 Tomcat
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
引入web模块默认就是使用嵌入式的Tomcat作为Servlet容器;
</dependency>
b)Jetty
<!-- 引入web模块 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!-- 由于tomcat优先级要高于jetty,我们这里需要排除掉tomcat -->
<exclusion>
<artifactId>spring-boot-starter-tomcat</artifactId>
<groupId>org.springframework.boot</groupId>
</exclusion>
</exclusions>
</dependency>
<!--引入其他的Servlet容器-->
<dependency>
<artifactId>spring-boot-starter-jetty</artifactId>
<groupId>org.springframework.boot</groupId>
</dependency>
c)Undertow
<!-- 引入web模块 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<!-- 同理 -->
<exclusion>
<artifactId>spring-boot-starter-tomcat</artifactId>
<groupId>org.springframework.boot</groupId>
</exclusion>
</exclusions>
</dependency>
<!--引入其他的Servlet容器-->
<dependency>
<artifactId>spring-boot-starter-undertow</artifactId>
<groupId>org.springframework.boot</groupId>
</dependency>
五、嵌入式Servlet容器自动配置原理
EmbeddedServletContainerAutoConfiguration:嵌入式的Servlet容器自动配置
@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 EmbeddedServletContainerAutoConfiguration {
@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
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
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
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Configuration
@ConditionalOnWebApplication
//导入BeanPostProcessorsRegistrar:给容器中导入一些组件,后置处理器的注册器
@Import(BeanPostProcessorsRegistrar.class)
public class EmbeddedServletContainerAutoConfiguration {
//@Import(BeanPostProcessorsRegistrar.class)
//org.springframework.boot.autoconfigure.web.EmbeddedServletContainerAutoConfiguration.BeanPostProcessorsRegistrar#registerBeanDefinitions
//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
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,
BeanDefinitionRegistry registry) {
if (this.beanFactory == null) {
return;
}
registerSyntheticBeanIfMissing(registry,
"embeddedServletContainerCustomizerBeanPostProcessor",
EmbeddedServletContainerCustomizerBeanPostProcessor.class);
registerSyntheticBeanIfMissing(registry,
"errorPageRegistrarBeanPostProcessor",
ErrorPageRegistrarBeanPostProcessor.class);
}
- EmbeddedServletContainerCustomizer:定制器帮我们修改了Servlet容器的配置
- EmbeddedServletContainerCustomizerBeanPostProcessor :后置处理器
//org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor#postProcessBeforeInitialization(java.lang.Object, java.lang.String)
//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;
}
//org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor#postProcessBeforeInitialization(org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer)
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);
}
}
//org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizerBeanPostProcessor#getCustomizers
private Collection<EmbeddedServletContainerCustomizer> getCustomizers() {
if (this.customizers == null) {
// Look up does not include the parent context
this.customizers = new ArrayList<EmbeddedServletContainerCustomizer>(
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
@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);
}
};
}
ServerProperties 就是 EmbeddedServletContainerCustomizer
@ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
public class ServerProperties
implements EmbeddedServletContainerCustomizer, EnvironmentAware, Ordered {
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
六、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?
a)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);
......
// Initialize other special beans in specific context subclasses.
onRefresh();
......
}
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
//org.springframework.boot.context.embedded.EmbeddedWebApplicationContext#onRefresh
@Override
protected void onRefresh() {
super.onRefresh();
try {
//5)、webioc容器会创建嵌入式的Servlet容器,createEmbeddedServletContainer()
createEmbeddedServletContainer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start embedded container",
ex);
}
}
//org.springframework.boot.context.embedded.EmbeddedWebApplicationContext#createEmbeddedServletContainer
private void createEmbeddedServletContainer() {
EmbeddedServletContainer localContainer = this.embeddedServletContainer;
ServletContext localServletContext = getServletContext();
if (localContainer == null && localServletContext == null) {
//6)、获取嵌入式的Servlet容器工厂:
EmbeddedServletContainerFactory containerFactory = getEmbeddedServletContainerFactory();
this.embeddedServletContainer = containerFactory
.getEmbeddedServletContainer(getSelfInitializer());
}
else if (localServletContext != null) {
try {
getSelfInitializer().onStartup(localServletContext);
}
catch (ServletException ex) {
throw new ApplicationContextException("Cannot initialize servlet context",
ex);
}
}
initPropertySources();
}
//org.springframework.boot.context.embedded.EmbeddedWebApplicationContext#getEmbeddedServletContainerFactory
protected EmbeddedServletContainerFactory getEmbeddedServletContainerFactory() {
// Use bean names so that we don't consider the hierarchy
//使用容器工厂获取嵌入式的Servlet容器:this.embeddedServletContainer = containerFactory .getEmbeddedServletContainer(getSelfInitializer());
String[] beanNames = getBeanFactory()
//前面自动配置类添加的工程类
.getBeanNamesForType(EmbeddedServletContainerFactory.class);
if (beanNames.length == 0) {
throw new ApplicationContextException(
"Unable to start EmbeddedWebApplicationContext due to missing "
+ "EmbeddedServletContainerFactory bean.");
}
if (beanNames.length > 1) {
throw new ApplicationContextException(
"Unable to start EmbeddedWebApplicationContext due to multiple "
+ "EmbeddedServletContainerFactory beans : "
+ StringUtils.arrayToCommaDelimitedString(beanNames));
}
return getBeanFactory().getBean(beanNames[0],
EmbeddedServletContainerFactory.class);
}
更多推荐
所有评论(0)