spring boot 源碼分析(四) 配置文件加載4 之 ConfigFileApplicationListener
1、前言java
上章咱們經過調試，找到了spring加載application.xml application.yml等配置文件的類，即本章要聊的web
ConfigFileApplicationListenerspring
2、看源碼apache
首先咱們看一下spring boot 的源碼app
package org.springframework.boot.context.config;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.stream.Collectors;
import org.apache.commons.logging.Log;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
import org.springframework.boot.context.event.ApplicationPreparedEvent;
import org.springframework.boot.context.properties.bind.Bindable;
import org.springframework.boot.context.properties.bind.Binder;
import org.springframework.boot.context.properties.bind.PropertySourcesPlaceholdersResolver;
import org.springframework.boot.context.properties.source.ConfigurationPropertySources;
import org.springframework.boot.env.EnvironmentPostProcessor;
import org.springframework.boot.env.PropertySourceLoader;
import org.springframework.boot.env.RandomValuePropertySource;
import org.springframework.boot.logging.DeferredLog;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.ConfigurationClassPostProcessor;
import org.springframework.context.event.SmartApplicationListener;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationAwareOrderComparator;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.SpringFactoriesLoader;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;
/**
* {@link EnvironmentPostProcessor} that configures the context environment by loading
* properties from well known file locations. By default properties will be loaded from
* 'application.properties' and/or 'application.yml' files in the following locations:
* <ul>
* <li>classpath:</li>
* <li>file:./</li>
* <li>classpath:config/</li>
* <li>file:./config/:</li>
* </ul>
* <p>
* Alternative search locations and names can be specified using
* {@link #setSearchLocations(String)} and {@link #setSearchNames(String)}.
* <p>
* Additional files will also be loaded based on active profiles. For example if a 'web'
* profile is active 'application-web.properties' and 'application-web.yml' will be
* considered.
* <p>
* The 'spring.config.name' property can be used to specify an alternative name to load
* and the 'spring.config.location' property can be used to specify alternative search
* locations or specific files.
* <p>
*
* @author Dave Syer
* @author Phillip Webb
* @author Stephane Nicoll
* @author Andy Wilkinson
* @author Eddú Meléndez
* @author Madhura Bhave
*/
public class ConfigFileApplicationListener
implements EnvironmentPostProcessor, SmartApplicationListener, Ordered {
private static final String DEFAULT_PROPERTIES = "defaultProperties";
// Note the order is from least to most specific (last one wins)
private static final String DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/";
private static final String DEFAULT_NAMES = "application";
private static final Set<String> NO_SEARCH_NAMES = Collections.singleton(null);
/**
* The "active profiles" property name.
*/
public static final String ACTIVE_PROFILES_PROPERTY = "spring.profiles.active";
/**
* The "includes profiles" property name.
*/
public static final String INCLUDE_PROFILES_PROPERTY = "spring.profiles.include";
/**
* The "config name" property name.
*/
public static final String CONFIG_NAME_PROPERTY = "spring.config.name";
/**
* The "config location" property name.
*/
public static final String CONFIG_LOCATION_PROPERTY = "spring.config.location";
/**
* The "config additional location" property name.
*/
public static final String CONFIG_ADDITIONAL_LOCATION_PROPERTY = "spring.config.additional-location";
/**
* The default order for the processor.
*/
public static final int DEFAULT_ORDER = Ordered.HIGHEST_PRECEDENCE + 10;
/**
* Name of the application configuration {@link PropertySource}.
*/
public static final String APPLICATION_CONFIGURATION_PROPERTY_SOURCE_NAME = "applicationConfigurationProperties";
private final DeferredLog logger = new DeferredLog();
private String searchLocations;
private String names;
private int order = DEFAULT_ORDER;
@Override
public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
return ApplicationEnvironmentPreparedEvent.class.isAssignableFrom(eventType)
|| ApplicationPreparedEvent.class.isAssignableFrom(eventType);
}
@Override
public boolean supportsSourceType(Class<?> aClass) {
return true;
}
@Override
public void onApplicationEvent(ApplicationEvent event) {
if (event instanceof ApplicationEnvironmentPreparedEvent) {
onApplicationEnvironmentPreparedEvent(
(ApplicationEnvironmentPreparedEvent) event);
}
if (event instanceof ApplicationPreparedEvent) {
onApplicationPreparedEvent(event);
}
}
private void onApplicationEnvironmentPreparedEvent(
ApplicationEnvironmentPreparedEvent event) {
List<EnvironmentPostProcessor> postProcessors = loadPostProcessors();
postProcessors.add(this);
AnnotationAwareOrderComparator.sort(postProcessors);
for (EnvironmentPostProcessor postProcessor : postProcessors) {
postProcessor.postProcessEnvironment(event.getEnvironment(),
event.getSpringApplication());
}
}
List<EnvironmentPostProcessor> loadPostProcessors() {
return SpringFactoriesLoader.loadFactories(EnvironmentPostProcessor.class,
getClass().getClassLoader());
}
@Override
public void postProcessEnvironment(ConfigurableEnvironment environment,
SpringApplication application) {
addPropertySources(environment, application.getResourceLoader());
}
private void onApplicationPreparedEvent(ApplicationEvent event) {
this.logger.replayTo(ConfigFileApplicationListener.class);
addPostProcessors(((ApplicationPreparedEvent) event).getApplicationContext());
}
/**
* Add config file property sources to the specified environment.
* @param environment the environment to add source to
* @param resourceLoader the resource loader
* @see #addPostProcessors(ConfigurableApplicationContext)
*/
protected void addPropertySources(ConfigurableEnvironment environment,
ResourceLoader resourceLoader) {
RandomValuePropertySource.addToEnvironment(environment);
new Loader(environment, resourceLoader).load();
}
/**
* Add appropriate post-processors to post-configure the property-sources.
* @param context the context to configure
*/
protected void addPostProcessors(ConfigurableApplicationContext context) {
context.addBeanFactoryPostProcessor(
new PropertySourceOrderingPostProcessor(context));
}
public void setOrder(int order) {
this.order = order;
}
@Override
public int getOrder() {
return this.order;
}
/**
* Set the search locations that will be considered as a comma-separated list. Each
* search location should be a directory path (ending in "/") and it will be prefixed
* by the file names constructed from {@link #setSearchNames(String) search names} and
* profiles (if any) plus file extensions supported by the properties loaders.
* Locations are considered in the order specified, with later items taking precedence
* (like a map merge).
* @param locations the search locations
*/
public void setSearchLocations(String locations) {
Assert.hasLength(locations, "Locations must not be empty");
this.searchLocations = locations;
}
/**
* Sets the names of the files that should be loaded (excluding file extension) as a
* comma-separated list.
* @param names the names to load
*/
public void setSearchNames(String names) {
Assert.hasLength(names, "Names must not be empty");
this.names = names;
}
/**
* {@link BeanFactoryPostProcessor} to re-order our property sources below any
* {@code @PropertySource} items added by the {@link ConfigurationClassPostProcessor}.
*/
private class PropertySourceOrderingPostProcessor
implements BeanFactoryPostProcessor, Ordered {
private ConfigurableApplicationContext context;
PropertySourceOrderingPostProcessor(ConfigurableApplicationContext context) {
this.context = context;
}
@Override
public int getOrder() {
return Ordered.HIGHEST_PRECEDENCE;
}
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
throws BeansException {
reorderSources(this.context.getEnvironment());
}
private void reorderSources(ConfigurableEnvironment environment) {
PropertySource<?> defaultProperties = environment.getPropertySources()
.remove(DEFAULT_PROPERTIES);
if (defaultProperties != null) {
environment.getPropertySources().addLast(defaultProperties);
}
}
}
/**
* Loads candidate property sources and configures the active profiles.
*/
private class Loader {
private final Log logger = ConfigFileApplicationListener.this.logger;
private final ConfigurableEnvironment environment;
private final ResourceLoader resourceLoader;
private final List<PropertySourceLoader> propertySourceLoaders;
private LinkedList<Profile> profiles;
private List<Profile> processedProfiles;
private boolean activatedProfiles;
private Map<Profile, MutablePropertySources> loaded;
private Map<DocumentsCacheKey, List<Document>> loadDocumentsCache = new HashMap<>();
Loader(ConfigurableEnvironment environment, ResourceLoader resourceLoader) {
this.environment = environment;
this.resourceLoader = (resourceLoader != null ? resourceLoader
: new DefaultResourceLoader());
this.propertySourceLoaders = SpringFactoriesLoader.loadFactories(
PropertySourceLoader.class, getClass().getClassLoader());
}
public void load() {
this.profiles = new LinkedList<>();
this.processedProfiles = new LinkedList<>();
this.activatedProfiles = false;
this.loaded = new LinkedHashMap<>();
initializeProfiles();
while (!this.profiles.isEmpty()) {
Profile profile = this.profiles.poll();
load(profile, this::getPositiveProfileFilter,
addToLoaded(MutablePropertySources::addLast, false));
this.processedProfiles.add(profile);
}
load(null, this::getNegativeProfileFilter,
addToLoaded(MutablePropertySources::addFirst, true));
addLoadedPropertySources();
}
/**
* Initialize profile information from both the {@link Environment} active
* profiles and any {@code spring.profiles.active}/{@code spring.profiles.include}
* properties that are already set.
*/
private void initializeProfiles() {
// The default profile for these purposes is represented as null. We add it
// first so that it is processed first and has lowest priority.
this.profiles.add(null);
Set<Profile> activatedViaProperty = getProfilesActivatedViaActiveProfileProperty();
processOtherActiveProfiles(activatedViaProperty);
// Any pre-existing active activeProfiles set via property sources (e.g.
// System
// properties) take precedence over those added in config files.
addActiveProfiles(activatedViaProperty);
if (this.profiles.size() == 1) { // only has null profile
for (String defaultProfileName : this.environment.getDefaultProfiles()) {
ConfigFileApplicationListener.Profile defaultProfile = new ConfigFileApplicationListener.Profile(
defaultProfileName, true);
this.profiles.add(defaultProfile);
}
}
}
private Set<Profile> getProfilesActivatedViaActiveProfileProperty() {
if (!this.environment.containsProperty(ACTIVE_PROFILES_PROPERTY)
&& !this.environment.containsProperty(INCLUDE_PROFILES_PROPERTY)) {
return Collections.emptySet();
}
Binder binder = Binder.get(this.environment);
Set<Profile> activeProfiles = new LinkedHashSet<>();
activeProfiles.addAll(getProfiles(binder, ACTIVE_PROFILES_PROPERTY));
activeProfiles.addAll(getProfiles(binder, INCLUDE_PROFILES_PROPERTY));
return activeProfiles;
}
private void processOtherActiveProfiles(Set<Profile> activatedViaProperty) {
List<Profile> otherActiveProfiles = Arrays
.stream(this.environment.getActiveProfiles()).map(Profile::new)
.filter((o) -> !activatedViaProperty.contains(o))
.collect(Collectors.toList());
this.profiles.addAll(otherActiveProfiles);
}
void addActiveProfiles(Set<Profile> profiles) {
if (this.activatedProfiles || profiles.isEmpty()) {
return;
}
addProfiles(profiles);
this.logger.debug("Activated activeProfiles "
+ StringUtils.collectionToCommaDelimitedString(profiles));
this.activatedProfiles = true;
removeUnprocessedDefaultProfiles();
}
void addProfiles(Set<Profile> profiles) {
for (Profile profile : profiles) {
this.profiles.add(profile);
addProfileToEnvironment(profile.getName());
}
}
private void removeUnprocessedDefaultProfiles() {
this.profiles.removeIf(
(profile) -> (profile != null && profile.isDefaultProfile()));
}
private DocumentFilter getPositiveProfileFilter(Profile profile) {
return (Document document) -> {
if (profile == null) {
return ObjectUtils.isEmpty(document.getProfiles());
}
return ObjectUtils.containsElement(document.getProfiles(),
profile.getName())
&& this.environment.acceptsProfiles(document.getProfiles());
};
}
private DocumentFilter getNegativeProfileFilter(Profile profile) {
return (Document document) -> (profile == null
&& !ObjectUtils.isEmpty(document.getProfiles())
&& this.environment.acceptsProfiles(document.getProfiles()));
}
private DocumentConsumer addToLoaded(
BiConsumer<MutablePropertySources, PropertySource<?>> addMethod,
boolean checkForExisting) {
return (profile, document) -> {
if (checkForExisting) {
for (MutablePropertySources merged : this.loaded.values()) {
if (merged.contains(document.getPropertySource().getName())) {
return;
}
}
}
MutablePropertySources merged = this.loaded.computeIfAbsent(profile,
(k) -> new MutablePropertySources());
addMethod.accept(merged, document.getPropertySource());
};
}
private void load(Profile profile, DocumentFilterFactory filterFactory,
DocumentConsumer consumer) {
getSearchLocations().forEach((location) -> {
boolean isFolder = location.endsWith("/");
Set<String> names = (isFolder ? getSearchNames() : NO_SEARCH_NAMES);
names.forEach(
(name) -> load(location, name, profile, filterFactory, consumer));
});
}
private void load(String location, String name, Profile profile,
DocumentFilterFactory filterFactory, DocumentConsumer consumer) {
if (!StringUtils.hasText(name)) {
for (PropertySourceLoader loader : this.propertySourceLoaders) {
if (canLoadFileExtension(loader, location)) {
load(loader, location, profile,
filterFactory.getDocumentFilter(profile), consumer);
}
}
}
for (PropertySourceLoader loader : this.propertySourceLoaders) {
for (String fileExtension : loader.getFileExtensions()) {
String prefix = location + name;
fileExtension = "." + fileExtension;
loadForFileExtension(loader, prefix, fileExtension, profile,
filterFactory, consumer);
}
}
}
private boolean canLoadFileExtension(PropertySourceLoader loader, String name) {
return Arrays.stream(loader.getFileExtensions())
.anyMatch((fileExtension) -> StringUtils.endsWithIgnoreCase(name,
fileExtension));
}
private void loadForFileExtension(PropertySourceLoader loader, String prefix,
String fileExtension, Profile profile,
DocumentFilterFactory filterFactory, DocumentConsumer consumer) {
DocumentFilter defaultFilter = filterFactory.getDocumentFilter(null);
DocumentFilter profileFilter = filterFactory.getDocumentFilter(profile);
if (profile != null) {
// Try profile-specific file & profile section in profile file (gh-340)
String profileSpecificFile = prefix + "-" + profile + fileExtension;
load(loader, profileSpecificFile, profile, defaultFilter, consumer);
load(loader, profileSpecificFile, profile, profileFilter, consumer);
// Try profile specific sections in files we've already processed
for (Profile processedProfile : this.processedProfiles) {
if (processedProfile != null) {
String previouslyLoaded = prefix + "-" + processedProfile
+ fileExtension;
load(loader, previouslyLoaded, profile, profileFilter, consumer);
}
}
}
// Also try the profile-specific section (if any) of the normal file
load(loader, prefix + fileExtension, profile, profileFilter, consumer);
}
private void load(PropertySourceLoader loader, String location, Profile profile,
DocumentFilter filter, DocumentConsumer consumer) {
try {
Resource resource = this.resourceLoader.getResource(location);
String description = getDescription(location, resource);
if (profile != null) {
description = description + " for profile " + profile;
}
if (resource == null || !resource.exists()) {
this.logger.trace("Skipped missing config " + description);
return;
}
if (!StringUtils.hasText(
StringUtils.getFilenameExtension(resource.getFilename()))) {
this.logger.trace("Skipped empty config extension " + description);
return;
}
String name = "applicationConfig: [" + location + "]";
List<Document> documents = loadDocuments(loader, name, resource);
if (CollectionUtils.isEmpty(documents)) {
this.logger.trace("Skipped unloaded config " + description);
return;
}
List<Document> loaded = new ArrayList<>();
for (Document document : documents) {
if (filter.match(document)) {
addActiveProfiles(document.getActiveProfiles());
addProfiles(document.getIncludeProfiles());
loaded.add(document);
}
}
Collections.reverse(loaded);
if (!loaded.isEmpty()) {
loaded.forEach((document) -> consumer.accept(profile, document));
this.logger.debug("Loaded config file " + description);
}
}
catch (Exception ex) {
throw new IllegalStateException("Failed to load property "
+ "source from location '" + location + "'", ex);
}
}
private List<Document> loadDocuments(PropertySourceLoader loader, String name,
Resource resource) throws IOException {
DocumentsCacheKey cacheKey = new DocumentsCacheKey(loader, resource);
List<Document> documents = this.loadDocumentsCache.get(cacheKey);
if (documents == null) {
List<PropertySource<?>> loaded = loader.load(name, resource);
documents = asDocuments(loaded);
this.loadDocumentsCache.put(cacheKey, documents);
}
return documents;
}
private List<Document> asDocuments(List<PropertySource<?>> loaded) {
if (loaded == null) {
return Collections.emptyList();
}
return loaded.stream().map((propertySource) -> {
Binder binder = new Binder(
ConfigurationPropertySources.from(propertySource),
new PropertySourcesPlaceholdersResolver(this.environment));
return new Document(propertySource,
binder.bind("spring.profiles", Bindable.of(String[].class))
.orElse(null),
getProfiles(binder, ACTIVE_PROFILES_PROPERTY),
getProfiles(binder, INCLUDE_PROFILES_PROPERTY));
}).collect(Collectors.toList());
}
private String getDescription(String location, Resource resource) {
try {
if (resource != null) {
String uri = resource.getURI().toASCIIString();
return String.format("'%s' (%s)", uri, location);
}
}
catch (IOException ex) {
}
return String.format("'%s'", location);
}
private Set<Profile> getProfiles(Binder binder, String name) {
return binder.bind(name, String[].class).map(this::asProfileSet)
.orElse(Collections.emptySet());
}
private Set<Profile> asProfileSet(String[] profileNames) {
List<Profile> profiles = new ArrayList<>();
for (String profileName : profileNames) {
profiles.add(new Profile(profileName));
}
return new LinkedHashSet<>(profiles);
}
private void addProfileToEnvironment(String profile) {
for (String activeProfile : this.environment.getActiveProfiles()) {
if (activeProfile.equals(profile)) {
return;
}
}
this.environment.addActiveProfile(profile);
}
private Set<String> getSearchLocations() {
if (this.environment.containsProperty(CONFIG_LOCATION_PROPERTY)) {
return getSearchLocations(CONFIG_LOCATION_PROPERTY);
}
Set<String> locations = getSearchLocations(
CONFIG_ADDITIONAL_LOCATION_PROPERTY);
locations.addAll(
asResolvedSet(ConfigFileApplicationListener.this.searchLocations,
DEFAULT_SEARCH_LOCATIONS));
return locations;
}
private Set<String> getSearchLocations(String propertyName) {
Set<String> locations = new LinkedHashSet<>();
if (this.environment.containsProperty(propertyName)) {
for (String path : asResolvedSet(
this.environment.getProperty(propertyName), null)) {
if (!path.contains("$")) {
path = StringUtils.cleanPath(path);
if (!ResourceUtils.isUrl(path)) {
path = ResourceUtils.FILE_URL_PREFIX + path;
}
}
locations.add(path);
}
}
return locations;
}
private Set<String> getSearchNames() {
if (this.environment.containsProperty(CONFIG_NAME_PROPERTY)) {
String property = this.environment.getProperty(CONFIG_NAME_PROPERTY);
return asResolvedSet(property, null);
}
return asResolvedSet(ConfigFileApplicationListener.this.names, DEFAULT_NAMES);
}
private Set<String> asResolvedSet(String value, String fallback) {
List<String> list = Arrays.asList(StringUtils.trimArrayElements(
StringUtils.commaDelimitedListToStringArray(value != null
? this.environment.resolvePlaceholders(value) : fallback)));
Collections.reverse(list);
return new LinkedHashSet<>(list);
}
private void addLoadedPropertySources() {
MutablePropertySources destination = this.environment.getPropertySources();
String lastAdded = null;
List<MutablePropertySources> loaded = new ArrayList<>(this.loaded.values());
Collections.reverse(loaded);
for (MutablePropertySources sources : loaded) {
for (PropertySource<?> source : sources) {
if (lastAdded == null) {
if (destination.contains(DEFAULT_PROPERTIES)) {
destination.addBefore(DEFAULT_PROPERTIES, source);
}
else {
destination.addLast(source);
}
}
else {
destination.addAfter(lastAdded, source);
}
lastAdded = source.getName();
}
}
}
}
/**
* A Spring Profile that can be loaded.
*/
private static class Profile {
private final String name;
private final boolean defaultProfile;
Profile(String name) {
this(name, false);
}
Profile(String name, boolean defaultProfile) {
Assert.notNull(name, "Name must not be null");
this.name = name;
this.defaultProfile = defaultProfile;
}
public String getName() {
return this.name;
}
public boolean isDefaultProfile() {
return this.defaultProfile;
}
@Override
public String toString() {
return this.name;
}
@Override
public int hashCode() {
return this.name.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj == null || obj.getClass() != getClass()) {
return false;
}
return ((Profile) obj).name.equals(this.name);
}
}
/**
* Cache key used to save loading the same document multiple times.
*/
private static class DocumentsCacheKey {
private final PropertySourceLoader loader;
private final Resource resource;
DocumentsCacheKey(PropertySourceLoader loader, Resource resource) {
this.loader = loader;
this.resource = resource;
}
@Override
public int hashCode() {
return this.loader.hashCode() * 31 + this.resource.hashCode();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
DocumentsCacheKey other = (DocumentsCacheKey) obj;
return this.loader.equals(other.loader)
&& this.resource.equals(other.resource);
}
}
/**
* A single document loaded by a {@link PropertySourceLoader}.
*/
private static class Document {
private final PropertySource<?> propertySource;
private String[] profiles;
private final Set<Profile> activeProfiles;
private final Set<Profile> includeProfiles;
Document(PropertySource<?> propertySource, String[] profiles,
Set<Profile> activeProfiles, Set<Profile> includeProfiles) {
this.propertySource = propertySource;
this.profiles = profiles;
this.activeProfiles = activeProfiles;
this.includeProfiles = includeProfiles;
}
public PropertySource<?> getPropertySource() {
return this.propertySource;
}
public String[] getProfiles() {
return this.profiles;
}
public Set<Profile> getActiveProfiles() {
return this.activeProfiles;
}
public Set<Profile> getIncludeProfiles() {
return this.includeProfiles;
}
@Override
public String toString() {
return this.propertySource.toString();
}
}
/**
* Factory used to create a {@link DocumentFilter}.
*/
@FunctionalInterface
private interface DocumentFilterFactory {
/**
* Create a filter for the given profile.
* @param profile the profile or {@code null}
* @return the filter
*/
DocumentFilter getDocumentFilter(Profile profile);
}
/**
* Filter used to restrict when a {@link Document} is loaded.
*/
@FunctionalInterface
private interface DocumentFilter {
boolean match(Document document);
}
/**
* Consumer used to handle a loaded {@link Document}.
*/
@FunctionalInterface
private interface DocumentConsumer {
void accept(Profile profile, Document document);
}
}
3、讀源碼dom
>類圖ide
咱們通用idea自帶的生成類圖的工具 CTRL+ALT+SHIFT+U生成本類的類圖工具
ConfigFileApplicationListener 主要實現瞭如下接口post
EnvironmentPostProcessor:用於環境的後處理this
SmartApplicationListener:是ApplicationListener的擴展，進一步暴露事件類型。
Ordered:用於將對象排序
>類的解釋
經過類上的註釋，咱們能夠知道關於該類的一些信息，
1.他默認會從classpath: 、file:./ 、classpath:config/ 、 file:./config/ 加載'application.properties' 和/或 'application.yml'
2.其餘配置也會根據active profiles 進行 加載 ， 如 active 此時被設置成 web, spring 加載的時候也會去加載 application-web.properties 和 application-web.yml
3.spring.config.name 屬性 可指定要加載的替代名稱，spring.config.location 屬性可指定替代的查找位置或文件
>屬性解析
1.經過看源碼能夠得知，他有這些屬性，這些屬性大部分是一些常量，定義了屬性名，配置文件查找的位置，順序，日誌等。
private static final String DEFAULT_PROPERTIES = "defaultProperties";
// Note the order is from least to most specific (last one wins)
private static final String DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/";
private static final String DEFAULT_NAMES = "application";
private static final Set<String> NO_SEARCH_NAMES = Collections.singleton(null);
/**
* The "active profiles" property name.
*/
public static final String ACTIVE_PROFILES_PROPERTY = "spring.profiles.active";
/**
* The "includes profiles" property name.
*/
public static final String INCLUDE_PROFILES_PROPERTY = "spring.profiles.include";
/**
* The "config name" property name.
*/
public static final String CONFIG_NAME_PROPERTY = "spring.config.name";
/**
* The "config location" property name.
*/
public static final String CONFIG_LOCATION_PROPERTY = "spring.config.location";
/**
* The "config additional location" property name.
*/
public static final String CONFIG_ADDITIONAL_LOCATION_PROPERTY = "spring.config.additional-location";
/**
* The default order for the processor.
*/
public static final int DEFAULT_ORDER = Ordered.HIGHEST_PRECEDENCE + 10;
/**
* Name of the application configuration {@link PropertySource}.
*/
public static final String APPLICATION_CONFIGURATION_PROPERTY_SOURCE_NAME = "applicationConfigurationProperties";
private final DeferredLog logger = new DeferredLog();
private String searchLocations;
private String names;
private int order = DEFAULT_ORDER;
>方法解析
首先咱們看一下他的實現接口中的方法
EnvironmentPostProcessor
public interface EnvironmentPostProcessor {
//用於給定環境的後處理
void postProcessEnvironment(ConfigurableEnvironment environment,
SpringApplication application);
}
SmartApplicationListener
public interface SmartApplicationListener extends ApplicationListener<ApplicationEvent>, Ordered {
//肯定這個監聽器是否支持給定的事件類型
boolean supportsEventType(Class<? extends ApplicationEvent> eventType);
//肯定這個監聽器是否支持給定的類型
boolean supportsSourceType(@Nullable Class<?> sourceType);
}
Ordered
public interface Ordered {
//做用於最高優先級
int HIGHEST_PRECEDENCE = Integer.MIN_VALUE;
//做用於最低優先級
int LOWEST_PRECEDENCE = Integer.MAX_VALUE;
//獲取排序的值
//高值會被執行爲低優先級 ， 所以 ， 最高優先級的對象會擁有最低的值(有點像servlet的load-on-startup)
//相同的值會致使受影響對象任意位置排序
int getOrder();
}
對比ConfigFileApplicationListener的繼承接口 EnvironmentPostProcessor, SmartApplicationListener, Ordered，咱們看如下ConfigFileApplicationListener對於這些接口的實現。
ConfigFileApplicationListener.java
@Override
public void postProcessEnvironment(ConfigurableEnvironment environment,
SpringApplication application) {
addPropertySources(environment, application.getResourceLoader());
}
//將配置文件屬性添加到特定的environment環境
protected void addPropertySources(ConfigurableEnvironment environment,
ResourceLoader resourceLoader) {
//添加random的相關功能加入到environment環境
RandomValuePropertySource.addToEnvironment(environment);
new Loader(environment, resourceLoader).load();
}
未完待續
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