一、基本原理
我们知道SpringMVC Web容器启动的时候会读取配置文件来进行Envirement的初始化设值，再根据Envirement中的信息去进行Web容器的初始化启动。spring_cloud_config就是对这里的拓展，其统一管理这些配置文件，然后其他的服务在启动的时候通过http请求去config_server读取本服务的配置环境。在这里，config_server就根据请求的相关信息如服务名称&环境信息&分支去读取其管理的配置文件，再将配置文件中的信息封装为一个Envirement返回给调用方。这就是config_server主要处理的逻辑，下面我们就来具体分析这个否则。
二、远程调用介绍1、调用方
1）、PropertySourceBootstrapConfiguration
调用方在去config_server读取Envirement的发起方法是PropertySourceBootstrapConfiguration
@Configuration@EnableConfigurationProperties(PropertySourceBootstrapProperties.class)public class PropertySourceBootstrapConfiguration implements ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {复制代码可以看到其是实现的ApplicationContextInitializer接口。下面我们来看其的方法调用：
@Overridepublic void initialize(ConfigurableApplicationContext applicationContext) {
CompositePropertySource composite = new CompositePropertySource(
BOOTSTRAP_PROPERTY_SOURCE_NAME);
AnnotationAwareOrderComparator.sort(this.propertySourceLocators); boolean empty = true;
ConfigurableEnvironment environment = applicationContext.getEnvironment(); for (PropertySourceLocator locator : this.propertySourceLocators) {
PropertySource<?> source = null;
source = locator.locate(environment); if (source == null) { continue;
}
......
} if (!empty) {
MutablePropertySources propertySources = environment.getPropertySources();
......
insertPropertySources(propertySources, composite);
......
}
}复制代码这里的逻辑主要是有两个：通过PropertySourceLocator去远程获取对应的PropertySource（其是从远程获取的Envirement提取的），然后再通过insertPropertySources方法将其添加到本服务的Envirement中MutablePropertySources propertySources = environment.getPropertySources()。
private void insertPropertySources(MutablePropertySources propertySources,
CompositePropertySource composite) {
MutablePropertySources incoming = new MutablePropertySources();
incoming.addFirst(composite);
PropertySourceBootstrapProperties remoteProperties = new PropertySourceBootstrapProperties();
Binder.get(environment(incoming)).bind("spring.cloud.config", Bindable.ofInstance(remoteProperties)); if (!remoteProperties.isAllowOverride() || (!remoteProperties.isOverrideNone()
&& remoteProperties.isOverrideSystemProperties())) {
propertySources.addFirst(composite); return;
} if (remoteProperties.isOverrideNone()) {
propertySources.addLast(composite); return;
} if (propertySources
.contains(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME)) { if (!remoteProperties.isOverrideSystemProperties()) {
propertySources.addAfter(
StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
composite);
} else {
propertySources.addBefore(
StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME,
composite);
}
} else {
propertySources.addLast(composite);
}
}复制代码可以看到这里还有决定是添加在addLast或addBefore。
2）、ConfigServicePropertySourceLocator
@Override@Retryable(interceptor = "configServerRetryInterceptor")public org.springframework.core.env.PropertySource<?> locate(
org.springframework.core.env.Environment environment) {
...... // Try all the labels until one works for (String label : labels) {
Environment result = getRemoteEnvironment(restTemplate, properties,
label.trim(), state); if (result != null) {
...... for (PropertySource source : result.getPropertySources()) { @SuppressWarnings("unchecked") Map<String, Object> map = (Map<String, Object>) source
.getSource();
composite.addPropertySource(new MapPropertySource(source.getName(), map));
}
}
......return composite;
}
}
}
......
}复制代码上面的this.propertySourceLocators其中就是ConfigServicePropertySourceLocator，这里就是通过getRemoteEnvironment方法去获取config_server中的信息，在获取其的result.getPropertySources()信息。
private Environment getRemoteEnvironment(RestTemplate restTemplate,
ConfigClientProperties properties, String label, String state) {
String path = "/{name}/{profile}";
String name = properties.getName();
String profile = properties.getProfile();
String token = properties.getToken(); int noOfUrls = properties.getUri().length; if (noOfUrls > 1) {
logger.info("Multiple Config Server Urls found listed.");
}
Object[] args = new String[] { name, profile }; if (StringUtils.hasText(label)) { if (label.contains("/")) {
label = label.replace("/", "(_)");
}
args = new String[] { name, profile, label };
path = path + "/{label}";
}
ResponseEntity<Environment> response = null; for (int i = 0; i < noOfUrls; i++) {
Credentials credentials = properties.getCredentials(i);
String uri = credentials.getUri();
String username = credentials.getUsername();
String password = credentials.getPassword();
logger.info("Fetching config from server at : " + uri); try {
HttpHeaders headers = new HttpHeaders();
addAuthorizationToken(properties, headers, username, password); if (StringUtils.hasText(token)) {
headers.add(TOKEN_HEADER, token);
} if (StringUtils.hasText(state) && properties.isSendState()) {
headers.add(STATE_HEADER, state);
} final HttpEntity<Void> entity = new HttpEntity<>((Void) null, headers);
response = restTemplate.exchange(uri + path, HttpMethod.GET, entity,
Environment.class, args);
......
Environment result = response.getBody(); return result;
} return null;
}复制代码这里就是远程调用config_server的方法。
2、被调用方（config_server）
1）、配置文件配置的信息
spring: cloud: config: #对应分支 # label: master profile: dev name: config-client复制代码
这里的spring.cloud.config.name - 对应的应用名称、spring.cloud.config.profile` - 对应的环境名称、spring.cloud.config.label` - 对应的分支名称(注释了)。
1）、EnvironmentController
@RestController@RequestMapping(method = RequestMethod.GET, path = "${spring.cloud.config.server.prefix:}")public class EnvironmentController {复制代码config_server就是用这个类去接收调用方获取Envirement请求的。这个类是有很多接收的方法：
@RequestMapping("/{name}/{profiles:.*[^-].*}")public Environment defaultLabel(@PathVariable String name, @PathVariable String profiles) { return labelled(name, profiles, null);
}@RequestMapping("/{name}/{profiles}/{label:.*}")public Environment labelled(@PathVariable String name, @PathVariable String profiles, @PathVariable String label) {
...... return environment;
}@RequestMapping("/{name}-{profiles}.properties")public ResponseEntity<String> properties(@PathVariable String name, @PathVariable String profiles, @RequestParam(defaultValue = "true") boolean resolvePlaceholders) throws IOException { return labelledProperties(name, profiles, null, resolvePlaceholders);
}@RequestMapping("/{label}/{name}-{profiles}.properties")public ResponseEntity<String> labelledProperties(@PathVariable String name, @PathVariable String profiles, @PathVariable String label, @RequestParam(defaultValue = "true") boolean resolvePlaceholders) throws IOException {
...... return getSuccess(propertiesString);
}@RequestMapping("{name}-{profiles}.json")public ResponseEntity<String> jsonProperties(@PathVariable String name, @PathVariable String profiles, @RequestParam(defaultValue = "true") boolean resolvePlaceholders) throws Exception { return labelledJsonProperties(name, profiles, null, resolvePlaceholders);
}@RequestMapping("/{label}/{name}-{profiles}.json")public ResponseEntity<String> labelledJsonProperties(@PathVariable String name, @PathVariable String profiles, @PathVariable String label, @RequestParam(defaultValue = "true") boolean resolvePlaceholders) throws Exception {
...... return getSuccess(json, MediaType.APPLICATION_JSON);
}@RequestMapping({ "/{name}-{profiles}.yml", "/{name}-{profiles}.yaml" })public ResponseEntity<String> yaml(@PathVariable String name, @PathVariable String profiles, @RequestParam(defaultValue = "true") boolean resolvePlaceholders) throws Exception { return labelledYaml(name, profiles, null, resolvePlaceholders);
}@RequestMapping({ "/{label}/{name}-{profiles}.yml",
"/{label}/{name}-{profiles}.yaml" })public ResponseEntity<String> labelledYaml(@PathVariable String name, @PathVariable String profiles, @PathVariable String label, @RequestParam(defaultValue = "true") boolean resolvePlaceholders) throws Exception {
validateProfiles(profiles);
...... return getSuccess(yaml);
}复制代码我们本次的请求是会进入第一个@RequestMapping("/{name}/{profiles:.*[^-].*}")，其调用的是第二个方法，这个方法就是我们本次的主要分析内容了。
三、config_server读取解析返回Envirement下面我们就来具体分析下labelled(@PathVariable String name, @PathVariable String profiles,@PathVariable String label)方法。
1、labelled(...)方法 (EnvironmentController)
@RequestMapping("/{name}/{profiles}/{label:.*}")public Environment labelled(@PathVariable String name, @PathVariable String profiles, @PathVariable String label) { if (name != null && name.contains("(_)")) { // "(_)" is uncommon in a git repo name, but "/" cannot be matched // by Spring MVC name = name.replace("(_)", "/");
} if (label != null && label.contains("(_)")) { // "(_)" is uncommon in a git branch name, but "/" cannot be matched // by Spring MVC label = label.replace("(_)", "/");
}
Environment environment = this.repository.findOne(name, profiles, label); if(!acceptEmpty && (environment == null || environment.getPropertySources().isEmpty())){ throw new EnvironmentNotFoundException("Profile Not found");
} return environment;
}复制代码1）、(_)替换符处理
可以看到这里有一种操作将(_)转换为/，这里其实就一种转换，因为如果将/放在请求上是代表的另一个请求，所以这里是有一个替换，这个替换时请求获取的时候可内容请求本身还有一层路径：
@Testpublic void applicationPlaceholderWithSlashForBinary() throws Exception { this.environmentRepository.setSearchLocations("classpath:/test/{application}"); byte[] resource = this.controller.binary("dev(_)spam", "bar", "", "foo.txt");
assertEquals("foo: dev_bar/spam", new String(resource));
}复制代码
例如这里其表示要获取的地址是dev/spam，可以看到也可以在搜索地址classpath:/test/{application}中写{application}这种替换符。
2）、this.repository.findOne(......)
private EnvironmentRepository repository;复制代码
Environment environment = this.repository.findOne(name, profiles, label);复制代码
这个就是环境仓库接口：
这里我们可以看到JGitEnvironmentRepository这个是用来处理Git仓库的，而我们本次是读取本地文件，其用的是NativeEnvironmentRepository。不过这里是用来代理模式：
public class EnvironmentEncryptorEnvironmentRepository implements EnvironmentRepository {复制代码@Overridepublic Environment findOne(String name, String profiles, String label) {
Environment environment = this.delegate.findOne(name, profiles, label); if (this.environmentEncryptor != null) {
environment = this.environmentEncryptor.decrypt(environment);
} if (!this.overrides.isEmpty()) {
environment.addFirst(new PropertySource("overrides", this.overrides));
} return environment;
}复制代码public class CompositeEnvironmentRepository implements EnvironmentRepository { protected List<EnvironmentRepository> environmentRepositories;复制代码@Overridepublic Environment findOne(String application, String profile, String label) {
Environment env = new Environment(application, new String[]{profile}, label, null, null); if(environmentRepositories.size() == 1) {
Environment envRepo = environmentRepositories.get(0).findOne(application, profile, label);
env.addAll(envRepo.getPropertySources());
env.setVersion(envRepo.getVersion());
env.setState(envRepo.getState());
} else { for (EnvironmentRepository repo : environmentRepositories) {
env.addAll(repo.findOne(application, profile, label).getPropertySources());
}
} return env;
}复制代码然后NativeEnvironmentRepository是放在environmentRepositories里，所以其是在CompositeEnvironmentRepository中再去调用NativeEnvironmentRepository。
三、NativeEnvironmentRepository1、基本结构
public class NativeEnvironmentRepository
implements EnvironmentRepository, SearchPathLocator, Ordered {复制代码2、变量
private String defaultLabel;/**
* Locations to search for configuration files. Defaults to the same as a Spring Boot
* app so [classpath:/,classpath:/config/,file:./,file:./config/].
*/private String[] searchLocations;/**
* Flag to determine how to handle exceptions during decryption (default false).
*/private boolean failOnError;/**
* Flag to determine whether label locations should be added.
*/private boolean addLabelLocations;/**
* Version string to be reported for native repository
*/private String version;private static final String[] DEFAULT_LOCATIONS = new String[] { "classpath:/", "classpath:/config/", "file:./", "file:./config/" };private ConfigurableEnvironment environment;复制代码defaultLabel：默认的label
searchLocations：表示进行文件获取的时候的搜索路径
addLabelLocations：表示lable的值是否也参加进对应的路径
DEFAULT_LOCATIONS：表示如果searchLocations没有设置值的时候是默认在这些路径下去搜索对应的文件
3、构造方法
public NativeEnvironmentRepository(ConfigurableEnvironment environment, NativeEnvironmentProperties properties) { this.environment = environment; this.addLabelLocations = properties.getAddLabelLocations(); this.defaultLabel = properties.getDefaultLabel(); this.failOnError = properties.getFailOnError(); this.order = properties.getOrder(); this.searchLocations = properties.getSearchLocations(); this.version = properties.getVersion();
}复制代码可以看到其主要是从NativeEnvironmentProperties中读取对应的信息进行赋值
4、NativeEnvironmentProperties
1）、结构
@ConfigurationProperties("spring.cloud.config.server.native")public class NativeEnvironmentProperties implements EnvironmentRepositoryProperties {复制代码所以你可以通过再配置文件中设置这些来给NativeEnvironmentRepository的属性进行赋值。
2）、变量
private Boolean failOnError = false;/** * Flag to determine whether label locations should be added. */private Boolean addLabelLocations = true;private String defaultLabel = "master";/** * Locations to search for configuration files. Defaults to the same as a Spring Boot * app so [classpath:/,classpath:/config/,file:./,file:./config/]. */private String[] searchLocations = new String[0];/** * Version string to be reported for native repository */private String version;private int order = Ordered.LOWEST_PRECEDENCE;复制代码
可以看到其的addLabelLocations是默认为true，defaultLabel默认为master分支
5、findOne(......)方法
@Overridepublic Environment findOne(String config, String profile, String label) {
SpringApplicationBuilder builder = new SpringApplicationBuilder(
PropertyPlaceholderAutoConfiguration.class);
ConfigurableEnvironment environment = getEnvironment(profile);
builder.environment(environment);
builder.web(WebApplicationType.NONE).bannerMode(Mode.OFF); if (!logger.isDebugEnabled()) { // Make the mini-application startup less verbose builder.logStartupInfo(false);
}
String[] args = getArgs(config, profile, label); // Explicitly set the listeners (to exclude logging listener which would change
// log levels in the caller)
builder.application()
.setListeners(Arrays.asList(new ConfigFileApplicationListener()));
ConfigurableApplicationContext context = builder.run(args);
environment.getPropertySources().remove("profiles"); try { return clean(new PassthruEnvironmentRepository(environment).findOne(config,
profile, label));
} finally {
context.close();
}
}复制代码
这个方法就是获取Environment的具体逻辑处理方法。这里首先是创建SpringApplicationBuilder对象。再进行对应的环境赋值，之后再进行Web容器的运行builder.run(args)，其是这里的运行主要是为了去触发ConfigFileApplicationListener监听器的逻辑，在这个ConfigFileApplicationListener中会完成对应文件的读取及构建对应的Envirement。下面我们就来看下这个具体的过程：
1）、getEnvironment(profile)
private ConfigurableEnvironment getEnvironment(String profile) {
ConfigurableEnvironment environment = new StandardEnvironment();
Map<String, Object> map = new HashMap<>();
map.put("spring.profiles.active", profile);
map.put("spring.main.web-application-type", "none");
environment.getPropertySources().addFirst(new MapPropertySource("profiles", map)); return environment;
}复制代码创建一个基本的Envirement StandardEnvironment 对象，然后就是将要获取profile(哪种环境)与key spring.profiles.active构建一个map，然后再以此创建一个对应的MapPropertySource添加到Environment中。
2）、getArgs(String application, String profile, String label)
private String[] getArgs(String application, String profile, String label) {
List<String> list = new ArrayList<String>();
String config = application; if (!config.startsWith("application")) {
config = "application," + config;
}
list.add("--spring.config.name=" + config);
list.add("--spring.cloud.bootstrap.enabled=false");
list.add("--encrypt.failOnError=" + this.failOnError);
list.add("--spring.config.location=" + StringUtils.arrayToCommaDelimitedString(
getLocations(application, profile, label).getLocations())); return list.toArray(new String[0]);
}复制代码这里首先我们需要注意，config = "application," + config，也就是说，SpringCloudConfig不单是会去读取传入的应用名称对应的文件，也会默认读取application.yml或application.properties文件。
然后就是--spring.config.location=(读取文件的时候是在那些路径下读取)的设置：
@Overridepublic Locations getLocations(String application, String profile, String label) {
String[] locations = this.searchLocations; if (this.searchLocations == null || this.searchLocations.length == 0) {
locations = DEFAULT_LOCATIONS;
}
Collection<String> output = new LinkedHashSet<String>(); if (label == null) {
label = defaultLabel;
} for (String location : locations) {
String[] profiles = new String[] { profile }; if (profile != null) {
profiles = StringUtils.commaDelimitedListToStringArray(profile);
}
String[] apps = new String[] { application }; if (application != null) {
apps = StringUtils.commaDelimitedListToStringArray(application);
} for (String prof : profiles) { for (String app : apps) {
String value = location;if (application != null) {
value = value.replace("{application}", app);
}if (prof != null) {
value = value.replace("{profile}", prof);
}if (label != null) {
value = value.replace("{label}", label);
}if (!value.endsWith("/")) {
value = value + "/";
}if (isDirectory(value)) {
output.add(value);
}
}
}
} if (this.addLabelLocations) { for (String location : locations) { if (StringUtils.hasText(label)) {
String labelled = location + label.trim() + "/";if (isDirectory(labelled)) {
output.add(labelled);
}
}
}
} return new Locations(application, profile, label, this.version,
output.toArray(new String[0]));
}复制代码1、首先是通过String[] locations = this.searchLocations，设置对应的目录地址，可以看到，如果locations目前还没有设置值，就将其设置默认值DEFAULT_LOCATIONS。
2、如果label也没有设值也通过label = defaultLabel设置默认值master。
3、再是通过String[] profiles = new String[] { profile }、String[] apps = new String[] { application }对profile、application 的解析。StringUtils.commaDelimitedListToStringArray(...)方法是通过,来对字符串解析切割。由这里我们看到profile&application 都是可以配置读取多个对应组合的文件的，其是用,来进行分隔。
4、之后再是对{application}这种的替换。再通过isDirectory方法来判断这个是不是地址：
private boolean isDirectory(String location) { return !location.contains("{") && !location.endsWith(".properties")
&& !location.endsWith(".yml") && !location.endsWith(".yaml");
}复制代码是的话就将其添加output中。
5、再通过对addLabelLocations的判断，看是否label也参与目录组合(默认为true)，是的会就通过String labelled = location + label.trim() + "/";来组合路径。
3）、findOne结束逻辑
对于整个getArgs方法来说，就是将Locations的locations返回。再通过arrayToCommaDelimitedString方法来将其拼接为一个字符串(以,划分)
public static String arrayToCommaDelimitedString(@Nullable Object[] arr) { return arrayToDelimitedString(arr, ",");
}复制代码最后对于findOne方法来说：
return clean(new PassthruEnvironmentRepository(environment).findOne(config, profile, label));复制代码
protected Environment clean(Environment value) {
Environment result = new Environment(value.getName(), value.getProfiles(),
value.getLabel(), this.version, value.getState()); for (PropertySource source : value.getPropertySources()) {
String name = source.getName(); if (this.environment.getPropertySources().contains(name)) { continue;
}
......
logger.info("Adding property source: " + name);
result.add(new PropertySource(name, source.getSource()));
} return result;
}复制代码这里的逻辑，其就是将前面创建读取赋值的StandardEnvirement中的PropertySources添加到Environment中来用于本次远程调用的返回(这个StandardEnvirement的赋值我们后面就会分析到)。注意这个Envirement与接口Envirement的区别，这个是package org.springframework.cloud.config.environment;包中的，这个Envirement是一个类。
public class Environment { private String name; private String[] profiles = new String[0]; private String label; private List<PropertySource> propertySources = new ArrayList<>(); private String version; private String state;复制代码下面我们来梳理下前面提到的ConfigFileApplicationListener对配置文件的读取解析主要就是这个类。
四、ConfigFileApplicationListener1、结构&变量
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;复制代码这里的变量主要是定义一些默认值，对于这些值通过前面的梳理，我们也是眼熟了。
2、postProcessEnvironment方法
@Overridepublic void postProcessEnvironment(ConfigurableEnvironment environment,
SpringApplication application) {
addPropertySources(environment, application.getResourceLoader());
}复制代码protected void addPropertySources(ConfigurableEnvironment environment,
ResourceLoader resourceLoader) {
RandomValuePropertySource.addToEnvironment(environment); new Loader(environment, resourceLoader).load();
}复制代码这就是触发加载配置文件并将其添加到environment中的MutablePropertySources中的逻辑。主要处理的类就是Loader。下面我们具体来分析下这个类。
五、Loader1、结构&变量
private class Loader { private final Log logger = ConfigFileApplicationListener.this.logger; private final ConfigurableEnvironment environment; private final ResourceLoader resourceLoader; private final List<PropertySourceLoader> propertySourceLoaders; private Deque<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());
}复制代码其是ConfigFileApplicationListener的内部类。
2、load方法
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(); if (profile != null && !profile.isDefaultProfile()) {
addProfileToEnvironment(profile.getName());
}
load(profile, this::getPositiveProfileFilter,
addToLoaded(MutablePropertySources::addLast, false)); this.processedProfiles.add(profile);
}
load(null, this::getNegativeProfileFilter,
addToLoaded(MutablePropertySources::addFirst, true));
addLoadedPropertySources();
}复制代码1）、这里先是通过initializeProfiles方法来对profiles赋值，然后对其进行遍历读取。
2）、先通过addProfileToEnvironment，来将该profile设置为激活的profile。
3）、再通过load(...)方法来进行解析读取配置文件。
4）、最后通过addLoadedPropertySources方法来将读取的PropertySource添加到envirement中。
5）、这些就是其的主要处理逻辑，为了更好的分层排版，我们将这个方法调用的其它方法也写在第二级。
3、initializeProfiles()
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 = getProfilesActivatedViaProperty(); this.profiles.addAll(getOtherActiveProfiles(activatedViaProperty)); // Any pre-existing active profiles 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()) {
Profile defaultProfile = new Profile(defaultProfileName, true); this.profiles.add(defaultProfile);
}
}
}复制代码这个方法是对profiles的赋值，可以看到这里首先是this.profiles.add(null)，这个赋值的意义类似与前面默认添加的application。例如你的应用名是configClient(application)，然后你要读取的环境是dev(profile)，所以拼接就可以是文件configClient_dev.yml，然后由于有这个赋值，其也会读取configClient.yml，不管你传入的profile是哪个，会以{application}.yml为公共的配置文件。同时如果this.profiles.size() == 1，表示这里只有默认的null，其也会添加一个默认的profile名称default，也就是RESERVED_DEFAULT_PROFILE_NAME = "default";。不过由于我们传入了dev，所以这里是有两个：
1）、getProfilesActivatedViaProperty()
从envirement中读取这些key 所对应的value。
4、addProfileToEnvironment(String profile)
private void addProfileToEnvironment(String profile) { for (String activeProfile : this.environment.getActiveProfiles()) { if (activeProfile.equals(profile)) { return;
}
} this.environment.addActiveProfile(profile);
}复制代码@Overridepublic void addActiveProfile(String profile) { if (logger.isDebugEnabled()) {
logger.debug("Activating profile '" + profile + "'");
}
validateProfile(profile);
doGetActiveProfiles(); synchronized (this.activeProfiles) { this.activeProfiles.add(profile);
}
}复制代码5、load(Profile profile, ...)
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));
});
}复制代码这里就是遍历搜索目录。
1）、getSearchLocations()
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;
}复制代码
如果有设置对应的读取路径，就直接返回设置的值。如果没有设置就返回默认的读取路径。
2）、getSearchNames()
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);
}复制代码读取应用名称，我们这里的就是application,config-client。
3）、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);
}
}
}复制代码这里的this.propertySourceLoaders (PropertySourceLoader)是用来加载对应文件的。这里其会有两个子类：
public class PropertiesPropertySourceLoader implements PropertySourceLoader { private static final String XML_FILE_EXTENSION = ".xml"; @Override
public String[] getFileExtensions() { return new String[] { "properties", "xml" };
}复制代码public class YamlPropertySourceLoader implements PropertySourceLoader { @Override
public String[] getFileExtensions() { return new String[] { "yml", "yaml" };
}复制代码可以看到这里的YamlPropertySourceLoader是用来读取以.yml、yaml为后缀的文件，PropertiesPropertySourceLoader是用来读取.properties、xml文件的。然后上面的load(loader, location, profile...)方法我们到后面再梳理，因为其会在下面的loadForFileExtension(...)方法中调用**（注意String prefix = location + name;）**。我们主要来看下一个对this.propertySourceLoaders的for循环。上面的是如果location本身就是一个文件具体的地址了，就调用load方法。
6、loadForFileExtension
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);
}复制代码这里我们需要注意对文件名称的整个拼接，profile != null就是表示如果profile是有值的，其的拼接是String profileSpecificFile = prefix + "-" + profile + fileExtension，如果其为null就是通过最后的load方法，其的加载名称是prefix + fileExtension。下面我们就来具体看下load方法。
7、load(PropertySourceLoader loader, String location,...)
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);
......
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());
addIncludedProfiles(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);
}
}
......
}复制代码1）、这里首先是通过Resource resource = this.resourceLoader.getResource(location)来加载对应的文件。
2）、再通过List<Document> documents = loadDocuments(loader, name, resource);来将对应的文件内容加载为Document
private static class Document {
private final PropertySource<?> propertySource;
private String[] profiles;
private final Set<Profile> activeProfiles;
private final Set<Profile> includeProfiles;复制代码3）、然后再遍历将其添加到loaded.add(document);中。
4）、再就是通过loaded.forEach((document) -> consumer.accept(profile, document)); consumer去处理了。这里是入参，我们一直回到最前面，其的传值是在一开始了
public void load() { this.profiles = new LinkedList<>(); this.processedProfiles = new LinkedList<>(); this.activatedProfiles = false; this.loaded = new LinkedHashMap<>();
initializeProfiles();
......
load(profile, this::getPositiveProfileFilter,
addToLoaded(MutablePropertySources::addLast, false));
......
addLoadedPropertySources();
}复制代码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());
};
}复制代码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());
};
}复制代码可以看到这里的DocumentConsumer其实是调用MutablePropertySources::addLast、this.loaded.computeIfAbsent(...)方法链。也就是读取Document的内容document.getPropertySource()，再调用的addLast方法来将其添加到this.loaded中(private Map<Profile, MutablePropertySources> loaded;)。
8、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();
}
}
}
}复制代码这个方法就是将前面读取到this.loaded中的内容通过addLoadedPropertySource方法将其添加到this.environment中。这里就填你上面说的对StandardEnvirement赋值的问题了。
至此，关于SpringCloudConfig读取远程配置文件的原理就梳理完成了。
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