SpringBott之Profile的理解和使用
一、Profile 介绍
1.1 Profile 的作用
在日常工作中，项目会处于不同的环境下，如开发、测试、生产等环境。针对不同的环境，各种配置信息也会不同，针对这种情况 Spring 提供了 Profile 机制，实现环境的切换。
1.2激活 Profile 方式
Spring 激活 Profile 依赖两个属性:
- spring.profiles.active
- spring.profiles.default
active 优先级比 default 高。
二、Profile 实践
2.1 激活单个配置文件
在 resources 目录下新建 application-dev.properties 文件：
fileName=dev
在 resources 目录下新建 application-test.properties 文件：
fileName=test
在 resources/application-test.properties 文件中启用当前环境为 dev:
spring.profiles.active=dev
新建启动加载器，获取 fileName 属性
@Component
public class GetAttributesApplicationRunner implements ApplicationRunner, EnvironmentAware {
private Environment environment;
@Override
public void run(ApplicationArguments args) throws Exception {
System.out.println(environment.getProperty("fileName"));
}
@Override
public void setEnvironment(Environment environment) {
this.environment = environment;
}
}
启动项目，查看控制台输出：
dev
2.2 激活多个配置文件
修改 resources /application-dev.properties 文件：
fileName=dev
age=18
修改resources /application-dev.properties 文件：
fileName=test
name=MarkLogZhu
在 resources/application-test.properties 文件中启用多个配置文件：
spring.profiles.include=test,dev
修改启动加载器，获取其他属性
@Override
public void run(ApplicationArguments args) throws Exception {
System.out.println(environment.getProperty("fileName"));
System.out.println(environment.getProperty("name"));
System.out.println(environment.getProperty("age"));
}
启动项目，查看控制台输出：
dev
MarkLogZhu
18
可以看到已经将所有的属性都读取到了，但是同名的属性会被覆盖掉，这点要特别注意。
三、SpringBoot 中 Profile 加载原理
在之前我们讲解 SpringBoot之属性配置 的时候有稍微提到了 ConfigFileApplicationListener .load 方法，我们来继续看下它的实现：
void load() {
FilteredPropertySource.apply(this.environment, DEFAULT_PROPERTIES, LOAD_FILTERED_PROPERTY,
(defaultProperties) -> {
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();
if (isDefaultProfile(profile)) {
addProfileToEnvironment(profile.getName());
}
load(profile, this::getPositiveProfileFilter,
addToLoaded(MutablePropertySources::addLast, false));
this.processedProfiles.add(profile);
}
load(null, this::getNegativeProfileFilter, addToLoaded(MutablePropertySources::addFirst, true));
addLoadedPropertySources();
applyActiveProfiles(defaultProperties);
});
}
3.1 initializeProfiles
初始化 Profiles，将所有的 profile 增加到 prifiles 集合中
private Deque<Profile> profiles;
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 = getProfilesFromProperty(ACTIVE_PROFILES_PROPERTY);
Set<Profile> includedViaProperty = getProfilesFromProperty(INCLUDE_PROFILES_PROPERTY);
List<Profile> otherActiveProfiles = getOtherActiveProfiles(activatedViaProperty, includedViaProperty);
this.profiles.addAll(otherActiveProfiles);
// Any pre-existing active profiles set via property sources (e.g.
// System properties) take precedence over those added in config files.
this.profiles.addAll(includedViaProperty);
addActiveProfiles(activatedViaProperty);
if (this.profiles.size() == 1) { // only has null profile
for (String defaultProfileName : this.environment.getDefaultProfiles()) {
Profile defaultProfile = new Profile(defaultProfileName, true);
this.profiles.add(defaultProfile);
}
}
}
3.2 循环 load
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));
});
}
进入 **getSearchLocations **方法：
// 配置文件属性名称，用来实现自定义配置文件名称
public static final String CONFIG_NAME_PROPERTY = "spring.config.name";
// 默认的配置文件名称
private static final String DEFAULT_NAMES = "application";
private Set<String> getSearchNames() {
// 如果存在该属性，就是用用户自定义的配置文件，否则使用默认的名称
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);
}
进入 load(location, name, profile, filterFactory, consumer)) 方法：
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);
return;
}
}
throw new IllegalStateException("File extension of config file location '" + location
+ "' is not known to any PropertySourceLoader. If the location is meant to reference "
+ "a directory, it must end in '/'");
}
Set<String> processed = new HashSet<>();
for (PropertySourceLoader loader : this.propertySourceLoaders) {
for (String fileExtension : loader.getFileExtensions()) {
if (processed.add(fileExtension)) {
loadForFileExtension(loader, location + name, "." + fileExtension, profile, filterFactory,
consumer);
}
}
}
}
进入loadForFileExtension(loader, location + name, "." + fileExtension, profile, filterFactory, consumer) 方法：
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);
}
最后进入 load(loader, prefix + fileExtension, profile, profileFilter, consumer) 方法：
private void load(PropertySourceLoader loader, String location, Profile profile, DocumentFilter filter,
DocumentConsumer consumer) {
try {
Resource resource = this.resourceLoader.getResource(location);
if (resource == null || !resource.exists()) {
if (this.logger.isTraceEnabled()) {
StringBuilder description = getDescription("Skipped missing config ", location, resource,
profile);
this.logger.trace(description);
}
return;
}
if (!StringUtils.hasText(StringUtils.getFilenameExtension(resource.getFilename()))) {
if (this.logger.isTraceEnabled()) {
StringBuilder description = getDescription("Skipped empty config extension ", location,
resource, profile);
this.logger.trace(description);
}
return;
}
String name = "applicationConfig: [" + location + "]";
List<Document> documents = loadDocuments(loader, name, resource);
if (CollectionUtils.isEmpty(documents)) {
if (this.logger.isTraceEnabled()) {
StringBuilder description = getDescription("Skipped unloaded config ", location, resource,
profile);
this.logger.trace(description);
}
return;
}
List<Document> loaded = new ArrayList<>();
for (Document document : documents) {
if (filter.match(document)) {
addActiveProfiles(document.getActiveProfiles());
addIncludedProfiles(document.getIncludeProfiles());
loaded.add(document);
}
}
Collections.reverse(loaded);
if (!loaded.isEmpty()) {
loaded.forEach((document) -> consumer.accept(profile, document));
if (this.logger.isDebugEnabled()) {
StringBuilder description = getDescription("Loaded config file ", location, resource, profile);
this.logger.debug(description);
}
}
}
catch (Exception ex) {
throw new IllegalStateException("Failed to load property source from location '" + location + "'", ex);
}
}
进入 List
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;
}
进入 List<PropertySource<?>> loaded = loader.load(name, resource);
@Override
public List<PropertySource<?>> load(String name, Resource resource) throws IOException {
Map<String, ?> properties = loadProperties(resource);
if (properties.isEmpty()) {
return Collections.emptyList();
}
return Collections
.singletonList(new OriginTrackedMapPropertySource(name, Collections.unmodifiableMap(properties), true));
}
循环 document 添加属性
List<Document> loaded = new ArrayList<>();
for (Document document : documents) {
if (filter.match(document)) {
addActiveProfiles(document.getActiveProfiles());
addIncludedProfiles(document.getIncludeProfiles());
loaded.add(document);
}
}
3.3 addLoadedPropertySources
private void addLoadedPropertySources() {
MutablePropertySources destination = this.environment.getPropertySources();
List<MutablePropertySources> loaded = new ArrayList<>(this.loaded.values());
Collections.reverse(loaded);
String lastAdded = null;
Set<String> added = new HashSet<>();
for (MutablePropertySources sources : loaded) {
for (PropertySource<?> source : sources) {
if (added.add(source.getName())) {
addLoadedPropertySource(destination, lastAdded, source);
lastAdded = source.getName();
}
}
}
}
3.4 applyActiveProfiles(defaultProperties)
// 应用活动配置文件
private void applyActiveProfiles(PropertySource<?> defaultProperties) {
List<String> activeProfiles = new ArrayList<>();
if (defaultProperties != null) {
Binder binder = new Binder(ConfigurationPropertySources.from(defaultProperties),
new PropertySourcesPlaceholdersResolver(this.environment));
activeProfiles.addAll(getDefaultProfiles(binder, "spring.profiles.include"));
if (!this.activatedProfiles) {
activeProfiles.addAll(getDefaultProfiles(binder, "spring.profiles.active"));
}
}
this.processedProfiles.stream().filter(this::isDefaultProfile).map(Profile::getName)
.forEach(activeProfiles::add);
this.environment.setActiveProfiles(activeProfiles.toArray(new String[0]));
}
