public interface PropertySourceLocator {

   /**
    * @param environment The current Environment.
    * @return A PropertySource, or null if there is none.
    * @throws IllegalStateException if there is a fail-fast condition.
    */
   PropertySource<?> locate(Environment environment);
}

public class GpDefineMapPropertySource extends MapPropertySource {
    /**
     * Create a new {@code MapPropertySource} with the given name and {@code Map}.
     *
     * @param name   the associated name
     * @param source the Map source (without {@code null} values in order to get
     *               consistent {@link #getProperty} and {@link #containsProperty} behavior)
     */
    public GpDefineMapPropertySource(String name, Map<String, Object> source) {
        super(name, source);
    }

    @Override
    public Object getProperty(String name) {
        return super.getProperty(name);
    public String[] getPropertyNames() {
        return super.getPropertyNames();
}

public class GpJsonPropertySourceLocator implements PropertySourceLocator {

    //json數(shù)據(jù)來源
    private final static String DEFAULT_LOCATION="classpath:gupao.json";
    //資源加載器
    private final ResourceLoader resourceLoader=new DefaultResourceLoader(getClass().getClassLoader());
    @Override
    public PropertySource<?> locate(Environment environment) {
        //設置屬性來源
        GpDefineMapPropertySource jsonPropertySource=new GpDefineMapPropertySource
                ("gpJsonConfig",mapPropertySource());
        return jsonPropertySource;
    }
    private Map<String,Object> mapPropertySource(){
        Resource resource=this.resourceLoader.getResource(DEFAULT_LOCATION);
        if(resource==null){
            return null;
        }
        Map<String,Object> result=new HashMap<>();
        JsonParser parser= JsonParserFactory.getJsonParser();
        Map<String,Object> fileMap=parser.parseMap(readFile(resource));
        processNestMap("",result,fileMap);
        return result;
    //加載文件并解析
    private String readFile(Resource resource){
        FileInputStream fileInputStream=null;
        try {
            fileInputStream=new FileInputStream(resource.getFile());
            byte[] readByte=new byte[(int)resource.getFile().length()];
            fileInputStream.read(readByte);
            return new String(readByte,"UTF-8");
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(fileInputStream!=null){
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        return null;
	//解析完整的url保存到result集合。 為了實現(xiàn)@Value注入
    private void processNestMap(String prefix,Map<String,Object> result,Map<String,Object> fileMap){
        if(prefix.length()>0){
            prefix+=".";
        for (Map.Entry<String, Object> entrySet : fileMap.entrySet()) {
            if (entrySet.getValue() instanceof Map) {
                processNestMap(prefix + entrySet.getKey(), result, (Map<String, Object>) entrySet.getValue());
            } else {
                result.put(prefix + entrySet.getKey(), entrySet.getValue());
}

org.springframework.cloud.bootstrap.BootstrapConfiguration=\
  com.gupaoedu.env.GpJsonPropertySourceLocator

@RestController
public class ConfigController {
    @Value("${custom.property.message}")
    private String name;
    
    @GetMapping("/")
    public String get(){
        String msg=String.format("配置值:%s",name);
        return msg;
    }
}

public ConfigurableApplicationContext run(String... args) {
   //省略代碼...
        prepareContext(context, environment, listeners, applicationArguments, printedBanner);
   //省略代碼
    return context;
}

@Override
public void initialize(ConfigurableApplicationContext applicationContext) {
    List<PropertySource<?>> composite = new ArrayList<>();
    //對propertySourceLocators數(shù)組進行排序，根據(jù)默認的AnnotationAwareOrderComparator
    AnnotationAwareOrderComparator.sort(this.propertySourceLocators);
    boolean empty = true;
    //獲取運行的環(huán)境上下文
    ConfigurableEnvironment environment = applicationContext.getEnvironment();
    for (PropertySourceLocator locator : this.propertySourceLocators) {
        //回調所有實現(xiàn)PropertySourceLocator接口實例的locate方法，并收集到source這個集合中。
        Collection<PropertySource<?>> source = locator.locateCollection(environment);
        if (source == null || source.size() == 0) { //如果source為空，直接進入下一次循環(huán)
            continue;
        }
        //遍歷source，把PropertySource包裝成BootstrapPropertySource加入到sourceList中。
        List<PropertySource<?>> sourceList = new ArrayList<>();
        for (PropertySource<?> p : source) {
            sourceList.add(new BootstrapPropertySource<>(p));
        }
        logger.info("Located property source: " + sourceList);
        composite.addAll(sourceList);//將source添加到數(shù)組
        empty = false; //表示propertysource不為空
    }
     //只有propertysource不為空的情況，才會設置到environment中
    if (!empty) {
        //獲取當前Environment中的所有PropertySources.
        MutablePropertySources propertySources = environment.getPropertySources();
        String logConfig = environment.resolvePlaceholders("${logging.config:}");
        LogFile logFile = LogFile.get(environment);
       // 遍歷移除bootstrapProperty的相關屬性
        for (PropertySource<?> p : environment.getPropertySources()) {
            
            if (p.getName().startsWith(BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
                propertySources.remove(p.getName());
            }
        }
        //把前面獲取到的PropertySource，插入到Environment中的PropertySources中。
        insertPropertySources(propertySources, composite);
        reinitializeLoggingSystem(environment, logConfig, logFile);
        setLogLevels(applicationContext, environment);
        handleIncludedProfiles(environment);
    }
}

public class TestApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext>{
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        ConfigurableEnvironment ce=applicationContext.getEnvironment();
        for(PropertySource<?> propertySource:ce.getPropertySources()){
            System.out.println(propertySource);
        }
        System.out.println("--------end");
    }
}

org.springframework.context.ApplicationContextInitializer= \
  com.gupaoedu.example.springcloudconfigserver9091.TestApplicationContextInitializer

ConfigurationPropertySourcesPropertySource {name='configurationProperties'}
StubPropertySource {name='servletConfigInitParams'}
StubPropertySource {name='servletContextInitParams'}
PropertiesPropertySource {name='systemProperties'}
OriginAwareSystemEnvironmentPropertySource {name='systemEnvironment'}
RandomValuePropertySource {name='random'}
MapPropertySource {name='configServerClient'}
MapPropertySource {name='springCloudClientHostInfo'}
OriginTrackedMapPropertySource {name='applicationConfig: [classpath:/application.yml]'}
MapPropertySource {name='kafkaBinderDefaultProperties'}
MapPropertySource {name='defaultProperties'}
MapPropertySource {name='springCloudDefaultProperties'}