关于java项目中如何读取配置文件

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关于java项目中如何读取配置文件

- Using multiple property files (via PropertyPlaceholderConfigurer) in multiple projects/modules

If you ensure that every place holder, in each of the contexts involved, is ignoring unresolvable keys then both of these approaches work. For example:

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<context:property-placeholder
location="classpath:dao.properties,
          classpath:services.properties,
          classpath:user.properties"
ignore-unresolvable="true"/>

or

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

- Spring MVC : read file from src/main/resources

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Resource resource = new ClassPathResource(fileLocationInClasspath);
InputStream resourceInputStream = resource.getInputStream();

- How do I load a resource and use its contents as a string in Spring

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<bean id="contents" class="org.apache.commons.io.IOUtils" factory-method="toString">
    <constructor-arg value="classpath:path/to/resource.txt" type="java.io.InputStream" />
</bean>

This solution requires Apache Commons IO.

Another solution, suggested by @Parvez, without Apache Commons IO dependency is

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<bean id="contents" class="java.lang.String">
    <constructor-arg>
        <bean class="org.springframework.util.FileCopyUtils" factory-method="copyToByteArray">
            <constructor-arg value="classpath:path/to/resource.txt" type="java.io.InputStream" />
        </bean>     
    </constructor-arg>
</bean>