blocks|key|3359758|text|可以，例如，您可以使用<property+name="defaultLocale"+value="#{+systemProperties['user.region']}"/>。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3359759|变量systemProperties是预定义的，请参见6.4.1+XML+based+configuration。|BOLD|3359760|entityMap|0|LINK|mutability|MUTABLE|url|http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html#expressions-beandef-xml-based^0|B|24|0|2|G|R|T|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@$9|U|A|V|B|H]]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|I|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|J|$K|$5|L|M|N|E|$O|P]]]]

Yes, you can do <code>&lt;property name="defaultLocale" value="#{ systemProperties['user.region']}"/&gt;</code> for instance.

The variable systemProperties is predefined, see <a href="http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html#expressions-beandef-xml-based">6.4.1 XML based configuration</a>.

blocks|key|1941765|text|很接近:o)+Spring3.0添加了Spring+Expression+Language。您可以使用|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1941766|<util:properties+id="dbProperties"+
++++location="classpath:config_#{systemProperties['env']}/db.properties"+/>|code-block|syntax|javascript|1941767|结合使用java+...+-Denv=QA应该可以解决您的问题。|style|CODE|1941768|另请注意@yiling的评论：|1941769|1941770|为了访问系统环境变量，也就是操作系统级变量，我们可以简单地在EL中使用"systemEnvironment“而不是"systemProperties”。像#{systemEnvironment['ENV_VARIABLE_NAME']}|blockquote|1941771|
一样|1941772|entityMap|0|LINK|mutability|MUTABLE|url|http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html^0|J|Q|0|0|0|4|H|0|0|0|25|15|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@$A|13|B|14|1|15]]|C|$]]|$1|D|3|E|5|F|7|16|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|17|8|@$A|18|B|19|K|L]]|9|@]|C|$]]|$1|M|3|N|5|6|7|1A|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|1B|8|@]|9|@]|C|$]]|$1|P|3|Q|5|R|7|1C|8|@$A|1D|B|1E|K|L]]|9|@]|C|$]]|$1|S|3|T|5|6|7|1F|8|@]|9|@]|C|$]]|$1|U|3|-4|5|6|7|1G|8|@]|9|@]|C|$]]]|V|$W|$5|X|Y|Z|C|$10|11]]]]

You are close :o)
Spring 3.0 adds <a href="http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/expressions.html" rel="noreferrer">Spring Expression Language</a>. 
You can use 

<pre><code>&lt;util:properties id="dbProperties" 
 location="classpath:config_#{systemProperties['env']}/db.properties" /&gt;
</code></pre>

Combined with <code>java ... -Denv=QA</code> should solve your problem.

Note also a comment by @yiling:

<blockquote>
 In order to access system environment variable, that is OS level
 variables as amoe commented, we can simply use "systemEnvironment"
 instead of "systemProperties" in that EL. Like
 <code>#{systemEnvironment['ENV_VARIABLE_NAME']}</code>
</blockquote>

blocks|key|1946323|text|检查this+article。它为您提供了几种方法，通过支持外部属性的PropertyPlaceholderConfigurer+(通过systemPropertiesMode属性)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1946324|entityMap|0|LINK|mutability|MUTABLE|url|https://web.archive.org/web/20151124064624/http://www.summa-tech.com/blog/2009/04/20/6-tips-for-managing-property-files-with-spring/|1|http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.html^0|Z|T|1W|K|2|C|0|Z|T|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]|$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]|N|$5|I|J|K|E|$L|O]]]]

Check <a href="https://web.archive.org/web/20151124064624/http://www.summa-tech.com/blog/2009/04/20/6-tips-for-managing-property-files-with-spring/" rel="noreferrer">this article</a>. It gives you several ways to do this, via the <a href="http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.html" rel="noreferrer"><code>PropertyPlaceholderConfigurer</code></a> which supports external properties (via the <code>systemPropertiesMode</code> property).

blocks|key|3359825|text|在bean定义中，确保包含"searchSystemEnvironment“并将其设置为"true”。如果你用它来构建一个文件的路径，把它指定为一个file:///+url。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3359826|例如，如果您的配置文件位于|3359827|/testapp/config/my.app.config.properties|code-block|syntax|javascript|3359828|然后像这样设置一个环境变量：|3359829|MY_ENV_VAR_PATH=/testapp/config|3359830|您的应用程序可以使用如下的bean定义加载文件：|3359831|例如：|3359832|<bean+class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer">
++++<property+name="systemPropertiesModeName"+value="SYSTEM_PROPERTIES_MODE_OVERRIDE"+/>
++++<property+name="searchSystemEnvironment"+value="true"+/>
++++<property+name="searchContextAttributes"+value="true"+/>
++++<property+name="contextOverride"+value="true"+/>
++++<property+name="ignoreResourceNotFound"+value="true"+/>
++++<property+name="locations">
++++++++<list>
++++++++++++<value>file:///${MY_ENV_VAR_PATH}/my.app.config.properties</value>
++++++++</list>
++++</property>
</bean>|3359833|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|F|7|11|8|@]|9|@]|A|$G|H]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

In your bean definition, make sure to include "searchSystemEnvironment" and set it to "true". And if you're using it to build a path to a file, specify it as a file:/// url.

So for example, if you have a config file located in 

<pre><code>/testapp/config/my.app.config.properties
</code></pre>

then set an environment variable like so:

<pre><code>MY_ENV_VAR_PATH=/testapp/config
</code></pre>

and your app can load the file using a bean definition like this:

e.g.

<pre><code>&lt;bean class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer"&gt;
 &lt;property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" /&gt;
 &lt;property name="searchSystemEnvironment" value="true" /&gt;
 &lt;property name="searchContextAttributes" value="true" /&gt;
 &lt;property name="contextOverride" value="true" /&gt;
 &lt;property name="ignoreResourceNotFound" value="true" /&gt;
 &lt;property name="locations"&gt;
 &lt;list&gt;
 &lt;value&gt;file:///${MY_ENV_VAR_PATH}/my.app.config.properties&lt;/value&gt;
 &lt;/list&gt;
 &lt;/property&gt;
&lt;/bean&gt;
</code></pre>

blocks|key|1946346|text|对于我的用例，我只需要访问系统属性，但在它们未定义的情况下提供默认值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1946347|这就是你怎么做的：|1946348|<bean+id="propertyPlaceholderConfigurer"+++
++++class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">++
++++<property+name="systemPropertiesModeName"+value="SYSTEM_PROPERTIES_MODE_OVERRIDE"+/>
++++<property+name="searchSystemEnvironment"+value="true"+/>
</bean>++
<bean+id="myBean"+class="path.to.my.BeanClass">
++++
++++<constructor-arg+value="${test.target.host:http://localhost:18888}"/>
</bean>|code-block|syntax|javascript|1946349|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

For my use case, I needed to access just the system properties, but provide default values in case they are undefined.

This is how you do it:

<pre class="lang-xml prettyprint-override"><code>&lt;bean id="propertyPlaceholderConfigurer" 
 class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"&gt; 
 &lt;property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" /&gt;
 &lt;property name="searchSystemEnvironment" value="true" /&gt;
&lt;/bean&gt; 
&lt;bean id="myBean" class="path.to.my.BeanClass"&gt;
 &lt;!-- can be overridden with -Dtest.target.host=http://whatever.com --&gt;
 &lt;constructor-arg value="${test.target.host:http://localhost:18888}"/&gt;
&lt;/bean&gt;
</code></pre>

blocks|key|1198936|text|使用Spring+EL，您可以按如下方式eis+example编写|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1198937|<bean+id="myBean"+class="path.to.my.BeanClass">
++++
++++<constructor-arg+value="#{systemProperties['test.target.host']+?:+'http://localhost:18888'}"/>
</bean>|code-block|syntax|javascript|1198938|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/18724139/391782^0|K|B|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Using Spring EL you can <a href="https://stackoverflow.com/a/18724139/391782">eis example</a> write as follows

<pre><code>&lt;bean id="myBean" class="path.to.my.BeanClass"&gt;
 &lt;!-- can be overridden with -Dtest.target.host=http://whatever.com --&gt;
 &lt;constructor-arg value="#{systemProperties['test.target.host'] ?: 'http://localhost:18888'}"/&gt;
&lt;/bean&gt;
</code></pre>

blocks|key|1196621|text|这就是你怎么做的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1196622|<bean+id="systemPrereqs"+class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"+scope="prototype">
+++++++++++++<property+name="targetObject"+value="#{@systemProperties}"+/>
+++++++++++++<property+name="targetMethod"+value="putAll"+/>
+++++++++++++<property+name="arguments">
+++++++++++++++++++<util:properties>
+++++++++++++++++++++++<prop+key="deployment.env">dev</prop>
+++++++++++++++++++</util:properties>
++++++++++++</property>
++++</bean>|code-block|syntax|javascript|1196623|但请记住，spring首先加载，然后它将加载此bean+MethodInvokingFactoryBean。因此，如果您正在尝试将其用于您的测试用例，那么请确保使用depends+on。例如，在这种情况下|1196624|如果您将其用于主类，最好使用pom.xml将此属性设置为|1196625|<systemProperty>
++++<name>deployment.env</name>
++++<value>dev</value>
</systemProperty>|1196626|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This is how you do it:

<pre><code>&lt;bean id="systemPrereqs" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean" scope="prototype"&gt;
 &lt;property name="targetObject" value="#{@systemProperties}" /&gt;
 &lt;property name="targetMethod" value="putAll" /&gt;
 &lt;property name="arguments"&gt;
 &lt;util:properties&gt;
 &lt;prop key="deployment.env"&gt;dev&lt;/prop&gt;
 &lt;/util:properties&gt;
 &lt;/property&gt;
 &lt;/bean&gt;
</code></pre>

But remember spring gets loaded first and then it will load this bean MethodInvokingFactoryBean. So if you are trying to use this for your test case then make sure that you use depends-on. For e.g. in this case


In case you are using it for your main class better to set this property using your pom.xml as

<pre><code>&lt;systemProperty&gt;
 &lt;name&gt;deployment.env&lt;/name&gt;
 &lt;value&gt;dev&lt;/value&gt;
&lt;/systemProperty&gt;
</code></pre>

blocks|key|4770895|text|现在你可以把|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|4770896|@Autowired
private+Environment+environment;|code-block|syntax|javascript|4770897|在您的@Component、@Bean等中，然后通过Environment类访问这些属性：|CODE|4770898|environment.getProperty("myProp");|4770899|4770900|@Bean中单个属性的|4770901|@Value("${my.another.property:123}")+//+value+after+':'+is+the+default
Integer+property;|4770902|4770903|是方便的@ConfigurationProperties+beans的另一种方式：|4770904|@ConfigurationProperties(prefix="my.properties.prefix")
public+class+MyProperties+{
++//+value+from+my.properties.prefix.myProperty+will+be+bound+to+this+variable
++String+myProperty;

++//+and+this+will+even+throw+a+startup+exception+if+the+property+is+not+found
++@javax.validation.constraints.NotNull
++String+myRequiredProperty;

++//getters
}

@Component
public+class+MyOtherBean+{
++@Autowired
++MyProperties+myProperties;
}|4770905|注意:只需记住在设置新的环境变量后重新启动eclipse。|4770906|entityMap^0|0|6|0|0|3|A|E|5|Q|B|0|0|0|0|5|0|0|0|4|O|0|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@$9|14|A|15|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@$9|18|A|19|B|M]|$9|1A|A|1B|B|M]|$9|1C|A|1D|B|M]]|D|@]|E|$]]|$1|N|3|O|5|H|7|1E|8|@]|D|@]|E|$I|J]]|$1|P|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1G|8|@$9|1H|A|1I|B|M]]|D|@]|E|$]]|$1|S|3|T|5|H|7|1J|8|@]|D|@]|E|$I|J]]|$1|U|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1L|8|@$9|1M|A|1N|B|M]]|D|@]|E|$]]|$1|X|3|Y|5|H|7|1O|8|@]|D|@]|E|$I|J]]|$1|Z|3|10|5|6|7|1P|8|@]|D|@]|E|$]]|$1|11|3|-4|5|6|7|1Q|8|@]|D|@]|E|$]]]|12|$]]

Nowadays you can put 

<pre><code>@Autowired
private Environment environment;
</code></pre>

in your <code>@Component</code>, <code>@Bean</code>, etc., and then access the properties through the <code>Environment</code> class:

<pre><code>environment.getProperty("myProp");
</code></pre>

<hr>

For a single property in a <code>@Bean</code>

<pre><code>@Value("${my.another.property:123}") // value after ':' is the default
Integer property;
</code></pre>

<hr>

Another way are the handy <code>@ConfigurationProperties</code> beans:

<pre><code>@ConfigurationProperties(prefix="my.properties.prefix")
public class MyProperties {
 // value from my.properties.prefix.myProperty will be bound to this variable
 String myProperty;

 // and this will even throw a startup exception if the property is not found
 @javax.validation.constraints.NotNull
 String myRequiredProperty;

 //getters
}

@Component
public class MyOtherBean {
 @Autowired
 MyProperties myProperties;
}
</code></pre>

Note: Just remember to restart eclipse after setting a new environment variable

blocks|key|3360014|text|您可以在属性文件中提到您的变量属性，并定义特定于环境的属性文件，如local.properties、production.propertied等。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3360015|现在，根据环境，这些属性文件中的一个可以在启动时调用的侦听器中读取，如ServletContextListener。|3360016|属性文件将包含各种键的环境特定值。|3360017|示例"local.propeties“|3360018|db.logsDataSource.url=jdbc:mysql://localhost:3306/logs
db.logsDataSource.username=root
db.logsDataSource.password=root

db.dataSource.url=jdbc:mysql://localhost:3306/main
db.dataSource.username=root
db.dataSource.password=root|code-block|syntax|javascript|3360019|示例"production.properties“|3360020|db.logsDataSource.url=jdbc:mariadb://111.111.111.111:3306/logs
db.logsDataSource.username=admin
db.logsDataSource.password=xyzqer

db.dataSource.url=jdbc:mysql://111.111.111.111:3306/carsinfo
db.dataSource.username=admin
db.dataSource.password=safasf@mn|3360021|为了使用这些属性文件，您可以使用REsource，如下所述|3360022|++++++++PropertyPlaceholderConfigurer+configurer+=+new+PropertyPlaceholderConfigurer();
++++++++ResourceLoader+resourceLoader+=+new+DefaultResourceLoader();

++++++++Resource+resource+=+resourceLoader.getResource("classpath:"%2BSystem.getenv("SERVER_TYPE")%2B"DB.properties");
++++++++configurer.setLocation(resource);
++++++++configurer.postProcessBeanFactory(beanFactory);|3360023|可以将SERVER_TYPE定义为具有适合本地和生产环境的值的环境变量。|3360024|通过这些更改，appplicationContext.xml将具有以下更改|3360025|<bean+id="dataSource"+class="org.apache.commons.dbcp.BasicDataSource">
+<property+name="driverClassName"+value="com.mysql.jdbc.Driver"+/>
++<property+name="url"+value="${db.dataSource.url}"+/>
++<property+name="username"+value="${db.dataSource.username}"+/>
++<property+name="password"+value="${db.dataSource.password}"+/>|3360026|希望这能有所帮助。|3360027|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|16|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|17|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|18|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|19|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|1A|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@]|A|$]]|$1|S|3|T|5|J|7|1C|8|@]|9|@]|A|$K|L]]|$1|U|3|V|5|6|7|1D|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|J|7|1F|8|@]|9|@]|A|$K|L]]|$1|10|3|11|5|6|7|1G|8|@]|9|@]|A|$]]|$1|12|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]]|13|$]]

You can mention your variable attributes in a property file and define environment specific property files like local.properties, production.propertied etc.

Now based on the environment, one of these property file can be read in one the listeners invoked at startup, like the ServletContextListener.

The property file will contain the the environment specific values for various keys.

Sample "local.propeties"

<pre><code>db.logsDataSource.url=jdbc:mysql://localhost:3306/logs
db.logsDataSource.username=root
db.logsDataSource.password=root

db.dataSource.url=jdbc:mysql://localhost:3306/main
db.dataSource.username=root
db.dataSource.password=root
</code></pre>

Sample "production.properties"

<pre><code>db.logsDataSource.url=jdbc:mariadb://111.111.111.111:3306/logs
db.logsDataSource.username=admin
db.logsDataSource.password=xyzqer

db.dataSource.url=jdbc:mysql://111.111.111.111:3306/carsinfo
db.dataSource.username=admin
db.dataSource.password=safasf@mn
</code></pre>

For using these properties file, you can make use of REsource as mentioned below

<pre><code> PropertyPlaceholderConfigurer configurer = new PropertyPlaceholderConfigurer();
 ResourceLoader resourceLoader = new DefaultResourceLoader();

 Resource resource = resourceLoader.getResource("classpath:"+System.getenv("SERVER_TYPE")+"DB.properties");
 configurer.setLocation(resource);
 configurer.postProcessBeanFactory(beanFactory);
</code></pre>

SERVER_TYPE can be defined as the environment variable with appropriate values for local and production environment. 

With these changes the appplicationContext.xml will have the following changes

<pre><code>&lt;bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"&gt;
 &lt;property name="driverClassName" value="com.mysql.jdbc.Driver" /&gt;
 &lt;property name="url" value="${db.dataSource.url}" /&gt;
 &lt;property name="username" value="${db.dataSource.username}" /&gt;
 &lt;property name="password" value="${db.dataSource.password}" /&gt;
</code></pre>

 

Hope this helps .

blocks|key|1946442|text|声明属性占位符，如下所示|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1946443|<bean+id="propertyPlaceholderConfigurer"+++
++++++++class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">++
++++<property+name="systemPropertiesModeName"+value="SYSTEM_PROPERTIES_MODE_OVERRIDE"+/>
++++<property+name="locations">
++++++++<list>
++++++++++++<value>file:///path.to.your.app.config.properties</value>
++++++++</list>
++++</property>
</bean>|code-block|syntax|javascript|1946444|然后假设您想要读取Tomcat+bean或任何bean的System.property("java.io.tmpdir")，然后在属性文件中添加以下内容：|offset|length|style|CODE|1946445|tomcat.tmp.dir=${java.io.tmpdir}|1946446|entityMap^0|0|0|S|X|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Declare the property place holder as follows

<pre><code>&lt;bean id="propertyPlaceholderConfigurer" 
 class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"&gt; 
 &lt;property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" /&gt;
 &lt;property name="locations"&gt;
 &lt;list&gt;
 &lt;value&gt;file:///path.to.your.app.config.properties&lt;/value&gt;
 &lt;/list&gt;
 &lt;/property&gt;
&lt;/bean&gt;
</code></pre>

Then lets say you want to read <code>System.property("java.io.tmpdir")</code> for your Tomcat bean or any bean then add following in your properties file:

<pre><code>tomcat.tmp.dir=${java.io.tmpdir}
</code></pre>

blocks|key|4771065|text|感谢@益灵。这只是个提示。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4771066|<bean+id="propertyConfigurer"
++++++++class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer">

++++<property+name="systemPropertiesModeName"+value="SYSTEM_PROPERTIES_MODE_OVERRIDE"+/>
++++<property+name="searchSystemEnvironment"+value="true"+/>
++++<property+name="locations">
++++++++<list>
++++++++++++<value>file:#{systemEnvironment['FILE_PATH']}/first.properties</value>
++++++++++++<value>file:#{systemEnvironment['FILE_PATH']}/second.properties</value>
++++++++++++<value>file:#{systemEnvironment['FILE_PATH']}/third.properties</value>
++++++++</list>
++++</property>
</bean>|code-block|syntax|javascript|4771067|在此之后，您应该有一个名为'FILE_PATH‘的环境变量。确保在创建该环境变量后重新启动终端/IDE。|4771068|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Thanks to @Yiling. That was a hint.

<pre><code>&lt;bean id="propertyConfigurer"
 class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer"&gt;

 &lt;property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" /&gt;
 &lt;property name="searchSystemEnvironment" value="true" /&gt;
 &lt;property name="locations"&gt;
 &lt;list&gt;
 &lt;value&gt;file:#{systemEnvironment['FILE_PATH']}/first.properties&lt;/value&gt;
 &lt;value&gt;file:#{systemEnvironment['FILE_PATH']}/second.properties&lt;/value&gt;
 &lt;value&gt;file:#{systemEnvironment['FILE_PATH']}/third.properties&lt;/value&gt;
 &lt;/list&gt;
 &lt;/property&gt;
&lt;/bean&gt;
</code></pre>

After this, you should have one environment variable named 'FILE_PATH'. Make sure you restart your terminal/IDE after creating that environment variable.

blocks|key|4771112|text|更新版(2020)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4771113|使用System.getenv("ENV_VARIABLE")|offset|length|4771114|entityMap|0|LINK|mutability|MUTABLE|url|https://www.tutorialspoint.com/java/lang/system_getenv_string.htm^0|0|2|T|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

Updated version (2020).
Use <a href="https://www.tutorialspoint.com/java/lang/system_getenv_string.htm" rel="nofollow noreferrer">System.getenv(&quot;ENV_VARIABLE&quot;)</a>

How to read the system environment variable in the application context?

I want something like :

<pre><code>&lt;util:properties id="dbProperties"
 location="classpath:config_DEV/db.properties" /&gt;
</code></pre>

or

<pre><code>&lt;util:properties id="dbProperties"
 location="classpath:config_QA/db.properties" /&gt;
</code></pre>

depending on the environement.

Can I have something like this in my application Context? 

<pre><code>&lt;util:properties id="dbProperties"
 location="classpath:config_${systemProperties.env}/db.properties" /&gt;
</code></pre>

where the actual val is set based on the SYSTEM ENVIRONMENT VARIABLE

I'm using Spring 3.0

how to read System environment variable in Spring applicationContext

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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如何在应用程序上下文中读取系统环境变量？我想要这样的东西：<util:properties id="dbProperties" location="classpath:config_DEV/db.properties" />或<util:properties id="dbProperties" ...

问如何在Spring applicationContext中读取系统环境变量
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