如果你的專案沒有配置錯誤，配置檔名稱也正常，還出現這個問題，那一定是你的yml檔案編碼的問題

先附上一張專案架構圖

當我啟動伺服器尋找配置檔案的時候，伺服器提示這樣的錯誤資訊

java.lang.IllegalStateException: Failed to load property source from location 'classpath:/application-dev.yml'
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:
 
549)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadForFileExtension(ConfigFileApplicationListener.java:488)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:468)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$
 
null$6(ConfigFileApplicationListener.java:450)
    at java.lang.Iterable.forEach(Iterable.java:75)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.lambda$load$7(ConfigFileApplicationListener.java:449)
    at java.lang.Iterable.forEach(Iterable.java:75)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:
 
446)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:336)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.addPropertySources(ConfigFileApplicationListener.java:215)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.postProcessEnvironment(ConfigFileApplicationListener.java:198)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent(ConfigFileApplicationListener.java:185)
    at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent(ConfigFileApplicationListener.java:171)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127)
    at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:74)
    at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:54)
    at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:361)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1258)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
    at com.dawn.rockcandy.RockCandyApplication.main(RockCandyApplication.java:11)
Caused by: org.yaml.snakeyaml.error.YAMLException: java.nio.charset.MalformedInputException: Input length = 1
    at org.yaml.snakeyaml.reader.StreamReader.update(StreamReader.java:254)
    at org.yaml.snakeyaml.reader.StreamReader.<init>(StreamReader.java:58)
    at org.yaml.snakeyaml.Yaml.loadAll(Yaml.java:537)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:166)
    at org.springframework.beans.factory.config.YamlProcessor.process(YamlProcessor.java:139)
    at org.springframework.boot.env.OriginTrackedYamlLoader.load(OriginTrackedYamlLoader.java:75)
    at org.springframework.boot.env.YamlPropertySourceLoader.load(YamlPropertySourceLoader.java:50)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.loadDocuments(ConfigFileApplicationListener.java:567)
    at org.springframework.boot.context.config.ConfigFileApplicationListener$Loader.load(ConfigFileApplicationListener.java:523)
    ... 23 common frames omitted
Caused by: java.nio.charset.MalformedInputException: Input length = 1
    at java.nio.charset.CoderResult.throwException(CoderResult.java:281)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:339)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
    at java.io.InputStreamReader.read(InputStreamReader.java:184)
    at org.yaml.snakeyaml.reader.UnicodeReader.read(UnicodeReader.java:125)
    at org.yaml.snakeyaml.reader.StreamReader.update(StreamReader.java:223)
    ... 31 common frames omitted

我的application.yml和application-dev.yml是沒有配置錯誤的，而且我的檔名稱是完全正常的，編譯後的target檔案裡面也有application-dev.yml，我就很納悶問題出在哪兒了！

開啟target檔案，檢視application-dev.yml檔案，發現這個檔案居然是空的，說明這個檔案編譯失敗了！！！

最後找到問題，因為這個檔案的編碼格式是GBK，專案的編碼格式是UTF-8，裡面有註釋，註釋亂碼，導致編譯失敗

1.修改你的編碼格式

2.刪除註釋