spring无法读取properties文件数据问题详解

1. controller中无法读取config.properties文件

controller中注入的@Value配置是从servlet-context.xml配置文件中获取的；service中注入的@Value配置可以从applicationContext.xml中获取的。所以，如果要在controller中注入属性配置，需要在相应servlet文件中添加配置，同applicationContext.xml中一样。

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <property name="locations">
    <list>
       <value>classpath:jdbc.properties</value>
      <value>classpath:config.properties</value>
     </list>
  </property>
  <property name="ignoreUnresolvablePlaceholders" value="true"/>
</bean>

2.service中无法读取config.properties文件

查看配置文件是否有多个。如果配置的路径是classpath:config.properties, 鼠标点击文件。如果显示”multiple implementations”, 表示有多个文件，查看其他的文件中是否有需要的配置项，没有的话，很可能就是加载了其他文件的配置项。这时，将路径改为classpath*:config.properties即可。

<context:property-placeholder
   ignore-unresolvable="true" location="classpath:/jdbc.properties, classpath*:/config.properties"/>

查看日志，发现：

[2017-01-05 16:45:02 INFO ] [main] (org.springframework.context.support.PropertySourcesPlaceholderConfigurer:?) - Loading properties file from URL [jar:file:/home/admin/creative-task/lib/xxxx-common-1.5.7.jar!/config.properties]

[2017-01-05 16:45:02 INFO ] [main] (org.springframework.context.support.PropertySourcesPlaceholderConfigurer:?) - Loading properties file from URL [file:/home/admin/creative-task/conf/config.properties]

加载了两个config.properties文件。

3.关于诊断：

1）首先确认是否正确加载了配置文件。查看日志：

正常日志如下：

[2017-01-05 16:45:02 INFO ] [main] (org.springframework.context.support.PropertySourcesPlaceholderConfigurer:?) - Loading properties file from URL [file:/home/admin/creative-task/conf/config.properties]

 异常日志如下：

[2017-01-05 16:39:39 ERROR] [main] (Main:22) - Could not load properties; nested exception is java.io.FileNotFoundException: class path resource [config.properties] cannot be opened because it does not exist

org.springframework.beans.factory.BeanInitializationException: Could not load properties; nested exception is java.io.FileNotFoundException: class path resource [config.properties] cannot be opened because it does not exist 

如果文件没有加载，则查看路径是否匹配等。

2）如果文件加载ok，查看配置属性是否正确加载。

查看tomcat启动的debug日志：

正常日志如下：

[2017-01-05 16:45:04 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [environmentProperties]

[2017-01-05 16:45:04 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [systemProperties]

[2017-01-05 16:45:04 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [systemEnvironment]

[2017-01-05 16:45:04 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Could not find key 'adx.id' in any property source. Returning [null]

[2017-01-05 16:45:04 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [localProperties]

[2017-01-05 16:45:04 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Found key 'adx.id' in [localProperties] with type [String] and value '1'

异常日志如下：

[2017-01-05 16:34:01 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [environmentProperties]

[2017-01-05 16:34:01 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [systemProperties]

[2017-01-05 16:34:01 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [systemEnvironment]

[2017-01-05 16:34:01 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Could not find key 'adx.id' in any property source. Returning [null]

[2017-01-05 16:34:01 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Searching for key 'adx.id' in [localProperties]

[2017-01-05 16:34:01 DEBUG] [main] (org.springframework.core.env.PropertySourcesPropertyResolver:?) - Could not find key 'adx.id' in any property source. Returning [null]

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