标签：body param fresh 注入 注册 准备 lua ada getpass
简介
可以用于从java主方法中引导和启动Spring应用程序的类，在默认情况下，通过以下步骤来启动应用：
- 创建一个ApplicationContext实例
- 注册CommandLinePropertySource用来暴露命令行参数作为spring的属性
- refresh applicationContext，加载所有的singleton bean
- 触发任何CommandLineRunner bean
自定义SpringApplication
默认的启动方式，代码如下，不做深入介绍
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| SpringApplication.run(AppBoot1.class, args);
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当然也可以做一些定制，如在Banner里面介绍的自定义banner，还有添加Listener等诸多设置，格式如下：
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| SpringApplication app = new SpringApplication(MySpringConfiguration.class);
app.setBannerMode(Banner.Mode.OFF);
app.run(args);
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使用Fluent Builder API进行构建
先上代码，如下：
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| new SpringApplicationBuilder()
.sources(ParentConfig.class)
.child(Child1Config.class)
.sibling(Child2Config.class)
.banner(new AppBanner())
.logStartupInfo(false)
.run(args);
@PropertySource("classpath:/parent.properties")
public class {
}
@PropertySource("classpath:/child1.properties")
public class Child1Config {
}
@PropertySource("classpath:/child2.properties")
public class Child2Config {
}
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使用SpringApplicationBuilder在构建分层的ApplicationContext应用的时候非常便利，但是官网给的代码示例很简单，对于一些初次介入的人可能理解上不是那么透彻。就上面的代码做一些简单的介绍
- .sources(ParentConfig.class)该方法是用来配置父配置，或主配置的。但是有坑!!!!请看上面的ParentConfig的代码，注解我使用的是@SpringBootApplication，如果你使用的是springboot的1.x的版本，那么你会很顺利，如果你正在研究springboot 2.x的版本，你会发现无论如何也无法启动成功（我被坑的好惨）…。聪明的人也许看到我的注释，没错换成@Configuration之后就可以正常工作。但是很抱歉，这是为什么暂时还没找到原因，在github上请教暂时也没得到正确的结果，后面继续研究，如果有人发现了其中的原因，请通知我一下
- .child(Child1Config.class)那么通过名字就可以看到是子环境了，Child1Config就是child1的配置文件。也许你的应用里有多个child，那么你可能会想用多个child().child()，那么这样你的第二个child不是parent的child，而是第一个child的child，parent的孙子。想要实现多个同级的孩子，可以使用代码中的.sibling(Child2Config.class)方法。这里同样存在一个springboot的版本改动问题，那就是如果你要在配置文件里面为child1配置一个context path，那么在版本1里面的方法是
server.contextPath=child1，但是如果使用版本2的朋友就需要做一点小改动了，改为server.servlet.contextPath=child1
可以参照github上的代码进行详细的理解github
事件和监听器
spring里面的监听器有三种实现方式：
- @EventListener注解方式
- 实现ApplicationListener接口
- 实现SmartApplicationListener接口
上面三种方式代码分别为
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| @Component
public class AnnotationRegisterListener {
@EventListener
public void register(UserRegisterEvent event) {
User user = event.getUser();
System.out.println("AnnotationRegisterListener " + user.getName() + ", " + user.getPassword());
}
}
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| @Component
public class RegisterListener implements ApplicationListener<UserRegisterEvent>{
@Override
public void onApplicationEvent(UserRegisterEvent event) {
User user = event.getUser();
System.out.println("RegisterListener " + user.getName() + ", " + user.getPassword());
}
}
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| @Component
public class UserRegisterListener implements SmartApplicationListener {
@Override
public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
return UserRegisterEvent.class.isAssignableFrom(eventType);
}
@Override
public boolean supportsSourceType(@Nullable Class<?> sourceType) {
return UserService.class.isAssignableFrom(sourceType);
}
@Override
public void onApplicationEvent(ApplicationEvent event) {
UserRegisterEvent userRegisterEvent = (UserRegisterEvent) event;
User user = userRegisterEvent.getUser();
System.out.println("UserRegisterListener " + user.getName() + ", " + user.getPassword());
}
@Override
public int getOrder() {
return 3;
}
}
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前两种实现方式比较简单，稍微介绍一下第三种，这种实现方式必须在supportsEventType和supportsSourceType同时返回true的情况下才会执行事件，具体如何返回true和false就看你自己的业务实现。在这里我使用了jdk的isAssignableFrom方法来判断父子关系的。
上面两种方式事件的执行顺序是无序的，第三种提供了一种指定属性的方法getOrder()
具体的isAssignableFrom是如何使用的，请看如下代码：
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| public class Animal {
}
public class Bird 大专栏 SpringBoot之SpringApplicationn class="keyword">extends Animal implements Fly {
}
public class Dove extends Bird {
}
public class Penguin extends Bird {
}
public interface Fly {
}
public class Demo03 {
public static void main(String[] args) {
assignOut(Animal.class, Animal.class);
assignOut(Animal.class, Bird.class);
assignOut(Bird.class, Animal.class);
assignOut(Animal.class, Dove.class);
assignOut(Penguin.class, Dove.class);
assignOut(Fly.class, Bird.class);
assignOut(Fly.class, Dove.class);
}
static void assignOut(Class cls1, Class cls2) {
System.out.println(cls1.getSimpleName() + " isAssignableFrom " + cls2.getSimpleName() + " : " + cls1.isAssignableFrom(cls2));
}
}
Animal isAssignableFrom Animal : true
Animal isAssignableFrom Bird : true
Bird isAssignableFrom Animal : false
Animal isAssignableFrom Dove : true
Penguin isAssignableFrom Dove : false
Fly isAssignableFrom Bird : true
Fly isAssignableFrom Dove : true
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SpringBoot启动过程中的事件及监听器
- ApplicationStartingEvent 应用开始启动时执行，在初始化listeners and initializers之前执行
- ApplicationEnvironmentPreparedEvent 环境准备好开始执行，上下文创建之前执行
- ApplicationPreparedEvent 应用准备好开始执行，即所有bean都已经加载完毕之后，在refresh方法执行之前执行
- ApplicationStartedEvent 应用启动后开始执行，即上下文被refreshed之后，任何的application和command-line runners调用前执行
- ApplicationReadyEvent 应用启动完毕开始执行，任何的application和command-line runners调用后执行，从此后可以服务request了
- ApplicationFailedEvent 启动时遇到异常执行
Listener的写法很简单，只以ApplicationStartingEvent为例，其他类似
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| public class MyApplicationStartedListener implements ApplicationListener<ApplicationStartedEvent> {
@Override
public void onApplicationEvent(ApplicationStartedEvent applicationStartedEvent) {
System.out.println("MyApplicationStartedListener...");
}
}
在main方法注入
SpringApplicationBuilder builder = new SpringApplicationBuilder();
builder.listeners(new MyApplicationStartingListener());
builder.listeners(new MyApplicationEnvironmentPreparedListener());
builder.listeners(new MyApplicationPreparedListener());
builder.listeners(new MyApplicationStartedListener());
builder.sources(AppBoot.class);
builder.run(args);
或者可以在META-INF/spring.factories中配置
org.springframework.context.ApplicationListener=com.smxknife.springboot.v2.ex03.listener.MyApplicationReadyListener
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看一下输出结果
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| 2018-03-03 01:24:06.387 INFO 5399 --- [ restartedMain] .ConditionEvaluationDeltaLoggingListener : Condition evaluation unchanged
2018-03-03 01:28:58.909 INFO 5399 --- [ Thread-28] ConfigServletWebServerApplicationContext : Closing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@58c49e73: startup date [Sat Mar 03 01:24:05 CST 2018]; root of context hierarchy
2018-03-03 01:28:58.913 INFO 5399 --- [ Thread-28] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
MyApplicationStartingListener...
MyApplicationEnvironmentPreparedListener...
. ____ _ __ _ _
/\ / ___'_ __ _ _(_)_ __ __ _
( ( )___ | '_ | '_| | '_ / _` |
\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |___, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.0.0.RC2)
2018-03-03 01:28:59.534 INFO 5399 --- [ restartedMain] com.smxknife.springboot.v2.ex03.AppBoot : Starting AppBoot on ShaoYundeMacBook-Pro.local with PID 5399 (/Users/ShaoYun/local/workstation/programs/smxknife/spring-boot/spring-boot-v2/spring-boot-v2-web/target/classes started by ShaoYun in /Users/ShaoYun/local/workstation/programs/smxknife/spring-boot)
2018-03-03 01:28:59.536 INFO 5399 --- [ restartedMain] com.smxknife.springboot.v2.ex03.AppBoot : No active profile set, falling back to default profiles: default
MyApplicationPreparedListener...
2018-03-03 01:28:59.539 INFO 5399 --- [ restartedMain] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@45b78eb1: startup date [Sat Mar 03 01:28:59 CST 2018]; root of context hierarchy
2018-03-03 01:29:00.304 INFO 5399 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 10101 (http)
2018-03-03 01:29:00.305 INFO 5399 --- [ restartedMain] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2018-03-03 01:29:00.305 INFO 5399 --- [ restartedMain] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.28
2018-03-03 01:29:00.316 INFO 5399 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-03-03 01:29:00.317 INFO 5399 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 778 ms
2018-03-03 01:29:00.338 INFO 5399 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2018-03-03 01:29:00.338 INFO 5399 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-03-03 01:29:00.338 INFO 5399 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-03-03 01:29:00.338 INFO 5399 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-03-03 01:29:00.338 INFO 5399 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-03-03 01:29:00.492 INFO 5399 --- [ restartedMain] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@45b78eb1: startup date [Sat Mar 03 01:28:59 CST 2018]; root of context hierarchy
2018-03-03 01:29:00.529 INFO 5399 --- [ restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/register]}" onto public java.lang.String com.smxknife.springboot.v2.ex03.web.controller.UserController.register(com.smxknife.springboot.v2.ex03.domain.User)
2018-03-03 01:29:00.533 INFO 5399 --- [ restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-03-03 01:29:00.534 INFO 5399 --- [ restartedMain] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-03-03 01:29:00.555 INFO 5399 --- [ restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-03-03 01:29:00.555 INFO 5399 --- [ restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-03-03 01:29:00.591 INFO 5399 --- [ restartedMain] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-03-03 01:29:00.648 INFO 5399 --- [ restartedMain] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729
2018-03-03 01:29:00.720 INFO 5399 --- [ restartedMain] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-03-03 01:29:00.738 INFO 5399 --- [ restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 10101 (http) with context path ''
2018-03-03 01:29:00.739 INFO 5399 --- [ restartedMain] com.smxknife.springboot.v2.ex03.AppBoot : Started AppBoot in 1.585 seconds (JVM running for 3711.163)
MyApplicationStartedListener...
MyApplicationReadyListener...
2018-03-03 01:29:00.741 INFO 5399 --- [ restartedMain] .ConditionEvaluationDeltaLoggingListener : Condition evaluation unchanged
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Listener的相关代码可以参照 github
SpringBoot之SpringApplication
标签：body param fresh 注入 注册 准备 lua ada getpass
原文地址：https://www.cnblogs.com/lijianming180/p/12251617.html
