org.springframework.core.env.MutablePropertySources#addBefore ( )源码实例Demo

private void insert(MutablePropertySources propertySources,
		PropertySource<?> propertySource) {
	if (propertySources
			.contains(BootstrapApplicationListener.BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
		if (DECRYPTED_BOOTSTRAP_PROPERTY_SOURCE_NAME
				.equals(propertySource.getName())) {
			propertySources.addBefore(
					BootstrapApplicationListener.BOOTSTRAP_PROPERTY_SOURCE_NAME,
					propertySource);
		}
		else {
			propertySources.addAfter(
					BootstrapApplicationListener.BOOTSTRAP_PROPERTY_SOURCE_NAME,
					propertySource);
		}
	}
	else {
		propertySources.addFirst(propertySource);
	}
}
 

private void addPropertySource(PropertySource<?> propertySource) {
	String name = propertySource.getName();
	MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();

	if (this.propertySourceNames.contains(name)) {
		// We've already added a version, we need to extend it
		PropertySource<?> existing = propertySources.get(name);
		if (existing != null) {
			PropertySource<?> newSource = (propertySource instanceof ResourcePropertySource ?
					((ResourcePropertySource) propertySource).withResourceName() : propertySource);
			if (existing instanceof CompositePropertySource) {
				((CompositePropertySource) existing).addFirstPropertySource(newSource);
			}
			else {
				if (existing instanceof ResourcePropertySource) {
					existing = ((ResourcePropertySource) existing).withResourceName();
				}
				CompositePropertySource composite = new CompositePropertySource(name);
				composite.addPropertySource(newSource);
				composite.addPropertySource(existing);
				propertySources.replace(name, composite);
			}
			return;
		}
	}

	if (this.propertySourceNames.isEmpty()) {
		propertySources.addLast(propertySource);
	}
	else {
		String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
		propertySources.addBefore(firstProcessed, propertySource);
	}
	this.propertySourceNames.add(name);
}
 

private void addPropertySource(PropertySource<?> propertySource) {
	String name = propertySource.getName();
	MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();

	if (this.propertySourceNames.contains(name)) {
		// We've already added a version, we need to extend it
		PropertySource<?> existing = propertySources.get(name);
		if (existing != null) {
			PropertySource<?> newSource = (propertySource instanceof ResourcePropertySource ?
					((ResourcePropertySource) propertySource).withResourceName() : propertySource);
			if (existing instanceof CompositePropertySource) {
				((CompositePropertySource) existing).addFirstPropertySource(newSource);
			}
			else {
				if (existing instanceof ResourcePropertySource) {
					existing = ((ResourcePropertySource) existing).withResourceName();
				}
				CompositePropertySource composite = new CompositePropertySource(name);
				composite.addPropertySource(newSource);
				composite.addPropertySource(existing);
				propertySources.replace(name, composite);
			}
			return;
		}
	}

	if (this.propertySourceNames.isEmpty()) {
		propertySources.addLast(propertySource);
	}
	else {
		String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
		propertySources.addBefore(firstProcessed, propertySource);
	}
	this.propertySourceNames.add(name);
}
 

@Override
public void contextLoaded(ConfigurableApplicationContext context) {
    // 从 ConfigurableApplicationContext 获取 ConfigurableEnvironment
    ConfigurableEnvironment environment = context.getEnvironment();
    MutablePropertySources propertySources = environment.getPropertySources();
    // 通过名称获取名为 "systemProperties" 的 PropertySource（实现使用常量）
    PropertySource propertySource = propertySources.get(StandardEnvironment.SYSTEM_PROPERTIES_PROPERTY_SOURCE_NAME);
    // 将 "systemProperties" 的 PropertySource 添加在 "contextPrepared" 之前（由 contextPrepared 方法添加），提高优先级
    propertySources.addBefore("contextPrepared", propertySource);
}
 

private void addNacosPropertySource(NacosPropertySource nacosPropertySource) {

		MutablePropertySources propertySources = environment.getPropertySources();

		boolean first = nacosPropertySource.isFirst();
		String before = nacosPropertySource.getBefore();
		String after = nacosPropertySource.getAfter();

		boolean hasBefore = !nullSafeEquals(DEFAULT_STRING_ATTRIBUTE_VALUE, before);
		boolean hasAfter = !nullSafeEquals(DEFAULT_STRING_ATTRIBUTE_VALUE, after);

		boolean isRelative = hasBefore || hasAfter;

		if (first) { // If First
			propertySources.addFirst(nacosPropertySource);
		}
		else if (isRelative) { // If relative
			if (hasBefore) {
				propertySources.addBefore(before, nacosPropertySource);
			}
			if (hasAfter) {
				propertySources.addAfter(after, nacosPropertySource);
			}
		}
		else {
			propertySources.addLast(nacosPropertySource); // default add last
		}
	}
 

private void addPropertySource(PropertySource<?> propertySource) {
	String name = propertySource.getName();
	MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();
	if (propertySources.contains(name) && this.propertySourceNames.contains(name)) {
		// We've already added a version, we need to extend it
		PropertySource<?> existing = propertySources.get(name);
		PropertySource<?> newSource = (propertySource instanceof ResourcePropertySource ?
				((ResourcePropertySource) propertySource).withResourceName() : propertySource);
		if (existing instanceof CompositePropertySource) {
			((CompositePropertySource) existing).addFirstPropertySource(newSource);
		}
		else {
			if (existing instanceof ResourcePropertySource) {
				existing = ((ResourcePropertySource) existing).withResourceName();
			}
			CompositePropertySource composite = new CompositePropertySource(name);
			composite.addPropertySource(newSource);
			composite.addPropertySource(existing);
			propertySources.replace(name, composite);
		}
	}
	else {
		if (this.propertySourceNames.isEmpty()) {
			propertySources.addLast(propertySource);
		}
		else {
			String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
			propertySources.addBefore(firstProcessed, propertySource);
		}
	}
	this.propertySourceNames.add(name);
}
 

private void addPropertySource(ResourcePropertySource propertySource) {
	String name = propertySource.getName();
	MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();
	if (propertySources.contains(name) && this.propertySourceNames.contains(name)) {
		// We've already added a version, we need to extend it
		PropertySource<?> existing = propertySources.get(name);
		if (existing instanceof CompositePropertySource) {
			((CompositePropertySource) existing).addFirstPropertySource(propertySource.withResourceName());
		}
		else {
			if (existing instanceof ResourcePropertySource) {
				existing = ((ResourcePropertySource) existing).withResourceName();
			}
			CompositePropertySource composite = new CompositePropertySource(name);
			composite.addPropertySource(propertySource.withResourceName());
			composite.addPropertySource(existing);
			propertySources.replace(name, composite);
		}
	}
	else {
		if (this.propertySourceNames.isEmpty()) {
			propertySources.addLast(propertySource);
		}
		else {
			String firstProcessed = this.propertySourceNames.get(this.propertySourceNames.size() - 1);
			propertySources.addBefore(firstProcessed, propertySource);
		}
	}
	this.propertySourceNames.add(name);
}