Spring Boot加載application.properties配置文件順序規則

SpringApplication會從如下路徑加載全部的application.properties文件：

一、file:./config/（當前目錄下的config文件夾） 二、file:./（當前目錄） 三、classpath:/config/（classpath下的config目錄） 四、classpath:/（classpath根目錄）

優先級由上至下。
注意：優先級是指屬性最後使用的值，而不是說僅僅掃描優先級高的路徑，不是發現了application.properties文件就中止。例如classpath:/config/和file:./config/都存在配置文件，那麼加載過程會加載classpath:/config/路徑下配置文件的全部屬性，而後再加載file:./config/路徑下配置文件的屬性並替換已有的屬性。此外，若是你在相同優先級位置同時有application.properties和application.yml，那麼application.yml裏面的屬性就會覆蓋application.properties裏的屬性。
若是你不想使用application.properties的格式命名配置文件，那麼能夠經過環境變量spring.config.name來設置文件名稱，例如：
$ java -jar myproject.jar --spring.config.name=example-sys.properties此時，要加載的配置文件名爲example-sys.properties。除了修更名稱，還可使用 spring.config.location 來添加要加載的路徑。例如咱們以這個命令啓動JVM：$ java -jar myapp.jar --spring.config.location=classpath:/myconfig/,file:./myconfig/
那麼加載application.properties文件的路徑以及優先級會變爲：

一、file:./myconfig/ 二、classpath:/myconfig/ 三、file:./config/ 四、file:./ 五、classpath:/config/ 六、classpath:/

spring.config.location環境變量也能夠直接設定到加載文件的名稱，例如：--spring.config.location=classpath:/default.properties
一般狀況下這樣作並無太大問題，可是結合到Profiles文件特性時，會致使沒法根據標記加載對應的Profiles文件。
因爲配置文件路徑和配置文件名稱在容器未啓動時就須要聲明，因此最好在OS的環境變量、JVM的系統環境變量或命令行參數就設定它。

注：

"file:"文件路徑前綴的相對路徑根目錄是 用戶當前目錄(即用戶運行jar包時的當前目錄)

 "classpath:"文件路徑前綴的相對路徑根目錄是 jar包內classes文件夾

classpath	優先本項目class路徑查找，沒有的話依次在其餘jar包中class路徑查找，找到第一個匹配的爲止
classpath*	加載到全部class路徑下的配置文件，包括jar包的class路徑下，最終加載全部匹配的
file	        經過URL加載，來源爲文件系統（注意文件讀取權限）
http	        經過URL加載，來源爲網絡
(none)	        根據 ApplicationContext 進行判斷（這個我沒試過）

classpath

<context:property-placeholder location="classpath:system.properties" />

舉個栗子：A項目中resources中存在system.properties，B項目中resources中也存在system.properties。A項目以jar包形式引入B項目。此時A項目spring配置classpath:system.properties加載到的是A項目本身的system.properties。可是若是A項目resources中沒有system.properties則最終結果加載到的是B.jar中的system.properties

classpath*

<context:property-placeholder location="classpath*:system.properties" />

舉個栗子：A項目中resources中存在system.properties，B項目中resources中也存在system.properties。A項目以jar包形式引入B項目。此時A項目spring配置classpath*:system.properties加載到的是A和B的system.properties
以下圖（我是引入的兩個jar都有同名配置文件）：

這裏你們可能會有疑問，同時引入了兩個同名配置文件，若是兩個同名配置文件中有一樣的配置，好比:
A項目system.properties

milo=a
milo1=a

B項目system.properties

milo=b
milo1=b

那麼最終引用的是哪一個？我這邊最終實驗結果是根據spring加載順序倒敘加載，直到找到匹配的值。並且值與值之間不影響，每次都按加載順序倒敘查找。即：若是spring加載順序爲A->B ,那麼最終取到的值爲：milo=b milo1=b。並且spring在取milo和milo1時都是按照spring加載順序倒敘取得。你們能夠經過三個配置文件狀況作下試驗。對spring熟悉的同窗也可找下源碼看一下。

附：

application.properties參數詳解

# ----------------------------------------
# CORE PROPERTIES
# ----------------------------------------

# SPRING 相關配置 (ConfigFileApplicationListener)
spring.config.name= # config file name (default to 'application')
spring.config.location= # location of config file

# profile相關配置
spring.profiles= # comma list of active profiles

# 系統配置相關參數 (SpringApplication)
spring.main.sources=
spring.main.web-environment= # detect by default
spring.main.show-banner=true
spring.main....= # see class for all properties

# 日誌配置相關參數
logging.path=/var/logs
logging.file=myapp.log
logging.config=

# IDENTITY (ContextIdApplicationContextInitializer)
spring.application.name=
spring.application.index=

# tomcat相關配置參數 (ServerProperties)
server.port=8080
server.address= # bind to a specific NIC
server.session-timeout= # session timeout in seconds
server.context-path= # the context path, defaults to '/'
server.servlet-path= # the servlet path, defaults to '/'
server.tomcat.access-log-pattern= # log pattern of the access log
server.tomcat.access-log-enabled=false # is access logging enabled
server.tomcat.protocol-header=x-forwarded-proto # ssl forward headers
server.tomcat.remote-ip-header=x-forwarded-for
server.tomcat.basedir=/tmp # base dir (usually not needed, defaults to tmp)
server.tomcat.background-processor-delay=30; # in seconds
server.tomcat.max-threads = 0 # number of threads in protocol handler
server.tomcat.uri-encoding = UTF-8 # character encoding to use for URL decoding

# springmvc相關配置參數 (HttpMapperProperties)
http.mappers.json-pretty-print=false # pretty print JSON
http.mappers.json-sort-keys=false # sort keys
spring.mvc.locale= # set fixed locale, e.g. en_UK
spring.mvc.date-format= # set fixed date format, e.g. dd/MM/yyyy
spring.mvc.message-codes-resolver-format= # PREFIX_ERROR_CODE / POSTFIX_ERROR_CODE
spring.view.prefix= # MVC view prefix
spring.view.suffix= # ... and suffix
spring.resources.cache-period= # cache timeouts in headers sent to browser
spring.resources.add-mappings=true # if default mappings should be added

# thymeleaf相關配置參數 (ThymeleafAutoConfiguration)
spring.thymeleaf.prefix=classpath:/templates/
spring.thymeleaf.suffix=.html
spring.thymeleaf.mode=HTML5
spring.thymeleaf.encoding=UTF-8
spring.thymeleaf.content-type=text/html # ;charset=<encoding> is added
spring.thymeleaf.cache=true # set to false for hot refresh

# freemark相關配置參數 (FreeMarkerAutoConfiguration)
spring.freemarker.allowRequestOverride=false
spring.freemarker.allowSessionOverride=false
spring.freemarker.cache=true
spring.freemarker.checkTemplateLocation=true
spring.freemarker.contentType=text/html
spring.freemarker.exposeRequestAttributes=false
spring.freemarker.exposeSessionAttributes=false
spring.freemarker.exposeSpringMacroHelpers=false
spring.freemarker.prefix=
spring.freemarker.requestContextAttribute=
spring.freemarker.settings.*=
spring.freemarker.suffix=.ftl
spring.freemarker.templateEncoding=UTF-8
spring.freemarker.templateLoaderPath=classpath:/templates/
spring.freemarker.viewNames= # whitelist of view names that can be resolved

# groovy模板相關配置參數 (GroovyTemplateAutoConfiguration)
spring.groovy.template.allowRequestOverride=false
spring.groovy.template.allowSessionOverride=false
spring.groovy.template.cache=true
spring.groovy.template.configuration.*= # See Groovy's TemplateConfiguration
spring.groovy.template.contentType=text/html
spring.groovy.template.prefix=classpath:/templates/
spring.groovy.template.suffix=.tpl
spring.groovy.template.templateEncoding=UTF-8
spring.groovy.template.viewNames= # whitelist of view names that can be resolved

# velocity模板相關配置參數 (VelocityAutoConfiguration)
spring.velocity.allowRequestOverride=false
spring.velocity.allowSessionOverride=false
spring.velocity.cache=true
spring.velocity.checkTemplateLocation=true
spring.velocity.contentType=text/html
spring.velocity.dateToolAttribute=
spring.velocity.exposeRequestAttributes=false
spring.velocity.exposeSessionAttributes=false
spring.velocity.exposeSpringMacroHelpers=false
spring.velocity.numberToolAttribute=
spring.velocity.prefix=
spring.velocity.properties.*=
spring.velocity.requestContextAttribute=
spring.velocity.resourceLoaderPath=classpath:/templates/
spring.velocity.suffix=.vm
spring.velocity.templateEncoding=UTF-8
spring.velocity.viewNames= # whitelist of view names that can be resolved

# INTERNATIONALIZATION (MessageSourceAutoConfiguration)
spring.messages.basename=messages
spring.messages.cacheSeconds=-1
spring.messages.encoding=UTF-8


# 安全相關配置參數 (SecurityProperties)
security.user.name=user # login username
security.user.password= # login password
security.user.role=USER # role assigned to the user
security.require-ssl=false # advanced settings ...
security.enable-csrf=false
security.basic.enabled=true
security.basic.realm=Spring
security.basic.path= # /**
security.headers.xss=false
security.headers.cache=false
security.headers.frame=false
security.headers.contentType=false
security.headers.hsts=all # none / domain / all
security.sessions=stateless # always / never / if_required / stateless
security.ignored=false

# 數據源相關配置參數(DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.name= # name of the data source
spring.datasource.initialize=true # populate using data.sql
spring.datasource.schema= # a schema (DDL) script resource reference
spring.datasource.data= # a data (DML) script resource reference
spring.datasource.platform= # the platform to use in the schema resource (schema-${platform}.sql)
spring.datasource.continueOnError=false # continue even if can't be initialized
spring.datasource.separator=; # statement separator in SQL initialization scripts
spring.datasource.driverClassName= # JDBC Settings...
spring.datasource.url=
spring.datasource.username=
spring.datasource.password=
spring.datasource.max-active=100 # Advanced configuration...
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10
spring.datasource.validation-query=
spring.datasource.test-on-borrow=false
spring.datasource.test-on-return=false
spring.datasource.test-while-idle=
spring.datasource.time-between-eviction-runs-millis=
spring.datasource.min-evictable-idle-time-millis=
spring.datasource.max-wait-millis=

# mongdb相關配置參數 (MongoProperties)
spring.data.mongodb.host= # the db host
spring.data.mongodb.port=27017 # the connection port (defaults to 27107)
spring.data.mongodb.uri=mongodb://localhost/test # connection URL
spring.data.mongo.repositories.enabled=true # if spring data repository support is enabled

# springDataJPA相關配置參數(JpaBaseConfiguration, HibernateJpaAutoConfiguration)
spring.jpa.properties.*= # properties to set on the JPA connection
spring.jpa.openInView=true
spring.jpa.show-sql=true
spring.jpa.database-platform=
spring.jpa.database=
spring.jpa.generate-ddl=false # ignored by Hibernate, might be useful for other vendors
spring.jpa.hibernate.naming-strategy= # naming classname
spring.jpa.hibernate.ddl-auto= # defaults to create-drop for embedded dbs
spring.data.jpa.repositories.enabled=true # if spring data repository support is enabled

# solr相關配置參數(SolrProperties})
spring.data.solr.host=http://127.0.0.1:8983/solr
spring.data.solr.zkHost=
spring.data.solr.repositories.enabled=true # if spring data repository support is enabled

# elasticsearch相關配置參數(ElasticsearchProperties})
spring.data.elasticsearch.cluster-name= # The cluster name (defaults to elasticsearch)
spring.data.elasticsearch.cluster-nodes= # The address(es) of the server node (comma-separated; if not specified starts a client node)
spring.data.elasticsearch.local=true # if local mode should be used with client nodes
spring.data.elasticsearch.repositories.enabled=true # if spring data repository support is enabled



# flyway相關配置參數(FlywayProperties)
flyway.locations=classpath:db/migrations # locations of migrations scripts
flyway.schemas= # schemas to update
flyway.initVersion= 1 # version to start migration
flyway.prefix=V
flyway.suffix=.sql
flyway.enabled=true
flyway.url= # JDBC url if you want Flyway to create its own DataSource
flyway.user= # JDBC username if you want Flyway to create its own DataSource
flyway.password= # JDBC password if you want Flyway to create its own DataSource

# liquibase相關配置參數(LiquibaseProperties)
liquibase.change-log=classpath:/db/changelog/db.changelog-master.yaml
liquibase.contexts= # runtime contexts to use
liquibase.default-schema= # default database schema to use
liquibase.drop-first=false
liquibase.enabled=true

# JMX
spring.jmx.enabled=true # Expose MBeans from Spring

# rabbitmq相關配置參數(RabbitProperties)
spring.rabbitmq.host= # connection host
spring.rabbitmq.port= # connection port
spring.rabbitmq.addresses= # connection addresses (e.g. myhost:9999,otherhost:1111)
spring.rabbitmq.username= # login user
spring.rabbitmq.password= # login password
spring.rabbitmq.virtualhost=
spring.rabbitmq.dynamic=

# redis相關配置參數(RedisProperties)
spring.redis.host=localhost # server host
spring.redis.password= # server password
spring.redis.port=6379 # connection port
spring.redis.pool.max-idle=8 # pool settings ...
spring.redis.pool.min-idle=0
spring.redis.pool.max-active=8
spring.redis.pool.max-wait=-1

# activemq相關配置參數(ActiveMQProperties)
spring.activemq.broker-url=tcp://localhost:61616 # connection URL
spring.activemq.user=
spring.activemq.password=
spring.activemq.in-memory=true # broker kind to create if no broker-url is specified
spring.activemq.pooled=false

# hornetq相關配置參數(HornetQProperties)
spring.hornetq.mode= # connection mode (native, embedded)
spring.hornetq.host=localhost # hornetQ host (native mode)
spring.hornetq.port=5445 # hornetQ port (native mode)
spring.hornetq.embedded.enabled=true # if the embedded server is enabled (needs hornetq-jms-server.jar)
spring.hornetq.embedded.serverId= # auto-generated id of the embedded server (integer)
spring.hornetq.embedded.persistent=false # message persistence
spring.hornetq.embedded.data-directory= # location of data content (when persistence is enabled)
spring.hornetq.embedded.queues= # comma separate queues to create on startup
spring.hornetq.embedded.topics= # comma separate topics to create on startup
spring.hornetq.embedded.cluster-password= # customer password (randomly generated by default)

# JMS (JmsProperties)
spring.jms.pub-sub-domain= # false for queue (default), true for topic

# springbatch相關配置參數(BatchDatabaseInitializer)
spring.batch.job.names=job1,job2
spring.batch.job.enabled=true
spring.batch.initializer.enabled=true
spring.batch.schema= # batch schema to load

# aop相關配置參數
spring.aop.auto=
spring.aop.proxy-target-class=

# FILE ENCODING (FileEncodingApplicationListener)
spring.mandatory-file-encoding=false

# SPRING SOCIAL (SocialWebAutoConfiguration)
spring.social.auto-connection-views=true # Set to true for default connection views or false if you provide your own

# SPRING SOCIAL FACEBOOK (FacebookAutoConfiguration)
spring.social.facebook.app-id= # your application's Facebook App ID
spring.social.facebook.app-secret= # your application's Facebook App Secret

# SPRING SOCIAL LINKEDIN (LinkedInAutoConfiguration)
spring.social.linkedin.app-id= # your application's LinkedIn App ID
spring.social.linkedin.app-secret= # your application's LinkedIn App Secret

# SPRING SOCIAL TWITTER (TwitterAutoConfiguration)
spring.social.twitter.app-id= # your application's Twitter App ID
spring.social.twitter.app-secret= # your application's Twitter App Secret

# SPRING MOBILE SITE PREFERENCE (SitePreferenceAutoConfiguration)
spring.mobile.sitepreference.enabled=true # enabled by default

# SPRING MOBILE DEVICE VIEWS (DeviceDelegatingViewResolverAutoConfiguration)
spring.mobile.devicedelegatingviewresolver.enabled=true # disabled by default
spring.mobile.devicedelegatingviewresolver.normalPrefix=
spring.mobile.devicedelegatingviewresolver.normalSuffix=
spring.mobile.devicedelegatingviewresolver.mobilePrefix=mobile/
spring.mobile.devicedelegatingviewresolver.mobileSuffix=
spring.mobile.devicedelegatingviewresolver.tabletPrefix=tablet/
spring.mobile.devicedelegatingviewresolver.tabletSuffix=

# ----------------------------------------
# ACTUATOR PROPERTIES
# ----------------------------------------

# MANAGEMENT HTTP SERVER (ManagementServerProperties)
management.port= # defaults to 'server.port'
management.address= # bind to a specific NIC
management.contextPath= # default to '/'

# ENDPOINTS (AbstractEndpoint subclasses)
endpoints.autoconfig.id=autoconfig
endpoints.autoconfig.sensitive=true
endpoints.autoconfig.enabled=true
endpoints.beans.id=beans
endpoints.beans.sensitive=true
endpoints.beans.enabled=true
endpoints.configprops.id=configprops
endpoints.configprops.sensitive=true
endpoints.configprops.enabled=true
endpoints.configprops.keys-to-sanitize=password,secret
endpoints.dump.id=dump
endpoints.dump.sensitive=true
endpoints.dump.enabled=true
endpoints.env.id=env
endpoints.env.sensitive=true
endpoints.env.enabled=true
endpoints.health.id=health
endpoints.health.sensitive=false
endpoints.health.enabled=true
endpoints.info.id=info
endpoints.info.sensitive=false
endpoints.info.enabled=true
endpoints.metrics.id=metrics
endpoints.metrics.sensitive=true
endpoints.metrics.enabled=true
endpoints.shutdown.id=shutdown
endpoints.shutdown.sensitive=true
endpoints.shutdown.enabled=false
endpoints.trace.id=trace
endpoints.trace.sensitive=true
endpoints.trace.enabled=true

# MVC ONLY ENDPOINTS
endpoints.jolokia.path=jolokia
endpoints.jolokia.sensitive=true
endpoints.jolokia.enabled=true # when using Jolokia
endpoints.error.path=/error

# JMX ENDPOINT (EndpointMBeanExportProperties)
endpoints.jmx.enabled=true
endpoints.jmx.domain= # the JMX domain, defaults to 'org.springboot'
endpoints.jmx.unique-names=false
endpoints.jmx.enabled=true
endpoints.jmx.staticNames=

# JOLOKIA (JolokiaProperties)
jolokia.config.*= # See Jolokia manual

# REMOTE SHELL
shell.auth=simple # jaas, key, simple, spring
shell.command-refresh-interval=-1
shell.command-path-pattern= # classpath*:/commands/**, classpath*:/crash/commands/**
shell.config-path-patterns= # classpath*:/crash/*
shell.disabled-plugins=false # don't expose plugins
shell.ssh.enabled= # ssh settings ...
shell.ssh.keyPath=
shell.ssh.port=
shell.telnet.enabled= # telnet settings ...
shell.telnet.port=
shell.auth.jaas.domain= # authentication settings ...
shell.auth.key.path=
shell.auth.simple.user.name=
shell.auth.simple.user.password=
shell.auth.spring.roles=

# GIT INFO
spring.git.properties= # resource ref to generated git info properties file

 

參考文獻：

SpringBoot配置文件application.properties參數詳解

Spring Boot學習總結（13）——Spring Boot加載application.properties配置文件順序規則