使用Spring加载属性(通过系统属性)

Question

我的问题如下:

我有server.properties不同的环境.通过名为的系统属性提供这些属性的路径propertyPath.如何指示我applicationContext.xml使用给定的propertyPath系统属性加载属性,而不需要一些丑陋的MethodInvokingBean调用System.getProperty('');

我的applicationContext.xml

<bean id="systemPropertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE"/>
        <property name="placeholderPrefix" value="sys{"/>
        <property name="properties">
            <props>
                <prop key="propertyPath">/default/path/to/server.properties</prop>
            </props>
        </property>
    </bean>


    <bean id="propertyResource" class="org.springframework.core.io.FileSystemResource" dependency-check="all" depends-on="systemPropertyConfigurer">
        <constructor-arg value="sys{propertyPath}"/>
    </bean>

    <bean id="serviceProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
        <property name="location" ref="propertyResource"/>
    </bean>

    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" ref="propertyResource"/>
        <property name="placeholderPrefix" value="prop{"/>

        <property name="ignoreUnresolvablePlaceholders" value="true"/>
        <property name="ignoreResourceNotFound" value="false"/>
    </bean>

    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
         <property name="jndiName" value="prop{datasource.name}"/>
    </bean>

有了这个配置,propertyResource也会抱怨

java.io.FileNotFoundException: sys{propertyPath} (The system cannot find the file specified)

有什么建议？;-)谢谢gabe

编辑:

现在我调试了bean的加载过程,似乎在创建之前调用了setLocationMethod的方法,因此使用"sys {propertyPath}"初始化了propertyResource.我玩了但没有运气.propertyConfigurersystemPropertyConfigurerdepends-on

Answer 1

好.我解决了 问题是我的PropertyPlaceholders都是BeanFactoryPostProcessor,它们在加载上下文后被处理,但属性是在之后设置的.因此,不可能将一个PropertyPlaceholder与另一个PropertyPlaceholder一起填充.

这是我的代码解决方案;-)

package property.util;

import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;

import java.io.IOException;
import java.util.Properties;

/**
 * ConfigurablePropertyPlaceholder takes instructions which SystemProperty
 * contains the path to the propertyfile to load.
 *
 * @author Gabe Kaelin
 * 
 */
public class ConfigurablePropertyPlaceholder extends PropertyPlaceholderConfigurer {


    private String propertyLocationSystemProperty;
    private String defaultPropertyFileName;


    public String getPropertyLocationSystemProperty() {
        return propertyLocationSystemProperty;
    }

    public void setPropertyLocationSystemProperty(String propertyLocationSystemProperty) {
        this.propertyLocationSystemProperty = propertyLocationSystemProperty;
    }

    public String getDefaultPropertyFileName() {
        return defaultPropertyFileName;
    }

    public void setDefaultPropertyFileName(String defaultPropertyFileName) {
        this.defaultPropertyFileName = defaultPropertyFileName;
    }

    /**
     * Overridden to fill the location with the path from the {@link #propertyLocationSystemProperty}
     *
     * @param props propeties instance to fill
     * @throws IOException
     */

    @Override
    protected void loadProperties(Properties props) throws IOException {
        Resource location = null;
        if(StringUtils.isNotEmpty(propertyLocationSystemProperty)){

            String propertyFilePath = System.getProperties().getProperty(propertyLocationSystemProperty);
            StringBuilder pathBuilder = new StringBuilder(propertyFilePath);

            if(StringUtils.isNotEmpty(defaultPropertyFileName) && !propertyFilePath.endsWith(defaultPropertyFileName)){
                pathBuilder.append("/").append(defaultPropertyFileName);
            }

            location = new FileSystemResource(pathBuilder.toString());
        }

        setLocation(location);
        super.loadProperties(props);
    }
}

相应的applicationContext.xml条目

<bean id="propertyConfigurer" class="property.util.ConfigurablePropertyPlaceholder">
  <property name="propertyLocationSystemProperty" value="propertyPath" />
  <property name="defaultPropertyFileName" value="server.properties" />
  <property name="ignoreResourceNotFound" value="false"/>
</bean>

java进程可以启动

java -DpropertyPath=/path/to/properties

它加载属性,它们在applicationContext.xml中可用