SpringBoot常用配置简介

SpringBoot常用配置简介

1. SpringBoot中几个常用的配置的简单介绍

一个简单的Spring.factories

# Bootstrap components
org.springframework.cloud.bootstrap.BootstrapConfiguration=\
org.springframework.cloud.config.server.bootstrap.ConfigServerBootstrapConfiguration

# Application listeners
org.springframework.context.ApplicationListener=\
org.springframework.cloud.config.server.bootstrap.ConfigServerBootstrapApplicationListener
# Autoconfiguration
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.cloud.config.server.config.EncryptionAutoConfiguration,\
org.springframework.cloud.config.server.config.SingleEncryptorAutoConfiguration

BootstrapConfiguration简介

Spring.factories中的配置项， org.springframework.cloud.bootstrap.BootstrapConfiguration，会在Spring启动之前的准备上下文阶段将其加入到容器中。我们在介绍 @Configuration配置解析一文中曾详细解释Configuration中的解析。BootstrapConfiguration是在刷新（refresh）阶段将class作为预选的配置类@Configuration注入到容器中的，在@Configuration配置解析阶段会解析此class。

加载BootstrapConfiguration配置的类

List<String> names = SpringFactoriesLoader
.loadFactoryNames(BootstrapConfiguration.class, classLoader);
for (String name : StringUtils.commaDelimitedListToStringArray(
environment.getProperty("spring.cloud.bootstrap.sources", ""))) {
names.add(name);
}
// TODO: is it possible or sensible to share a ResourceLoader?
SpringApplicationBuilder builder = new SpringApplicationBuilder()
.profiles(environment.getActiveProfiles()).bannerMode(Mode.OFF)
.environment(bootstrapEnvironment)
.properties("spring.application.name:" + configName)
.registerShutdownHook(false).logStartupInfo(false).web(false);
List<Class<?>> sources = new ArrayList<>();
for (String name : names) {
Class<?> cls = ClassUtils.resolveClassName(name, null);
try {
cls.getDeclaredAnnotations();
}
catch (Exception e) {
continue;
}
sources.add(cls);
}
builder.sources(sources.toArray(new Class[sources.size()]));
AnnotationAwareOrderComparator.sort(sources);
final ConfigurableApplicationContext context = builder.run();

加载BootstrapConfiguration配置的类

private void prepareContext(ConfigurableApplicationContext context,ConfigurableEnvironment environment, SpringApplicationRunListeners listeners,ApplicationArguments applicationArguments, Banner printedBanner) {
context.setEnvironment(environment);
postProcessApplicationContext(context);
applyInitializers(context);
listeners.contextPrepared(context);
if (this.logStartupInfo) {
logStartupInfo(context.getParent() == null);
logStartupProfileInfo(context);
}
// Add boot specific singleton beans
context.getBeanFactory().registerSingleton("springApplicationArguments",
applicationArguments);
if (printedBanner != null) {
context.getBeanFactory().registerSingleton("springBootBanner", printedBanner);
}

// Load the sources
Set<Object> sources = getSources();//获取需要加载的class源
Assert.notEmpty(sources, "Sources must not be empty");
load(context, sources.toArray(new Object[sources.size()]));//加载class
listeners.contextLoaded(context);
}

ApplicationListener简介

org.springframework.context.ApplicationListener会在SpringBoot中几个典型事件产生后调用onApplicationEvent方法。详见Spring事件发布系统。

Autoconfiguration简介

org.springframework.boot.autoconfigure.EnableAutoConfiguration是SpringBoot中最常见配置，用于自动配置。只要有@EnableAutoConfiguration注解，该配置的所有类都会自动加载到Spring容器中。