码迷,mamicode.com
首页 > 编程语言 > 详细

springmvc加载xml文件读取本地properties配置文件

时间:2015-06-19 18:26:55      阅读:761      评论:0      收藏:0      [点我收藏+]

标签:

org.springframework.beans.factory.config.PropertyPlaceholderConfigurer。由这个类别,您可以将一些组态设定,移出至.properties档案中,如此的安排可以让XML定义档负责系统相关设定,而.properties档可 以作为客户根据需求,自定义一些相关的参数。实际上,PropertyPlaceholderConfigurer起的作用就是将占位符指向的数据库配置 信息放在bean中定义的工具。

(1)使用以下方式读取单个本地文件到xml中:

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">      
     <property name="location">  
               <value>file:/opt/config/config1.properties</value>        
    </property> 
 </bean>        

(2)使用以下方式读取多个本地文件到xml中:

  <!-- 使用spring提供的PropertyPlaceholderConfigurer读取properties -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <!-- 属性名是 locations,使用子标签<list></list>可以指定多个数据库的配置文件,这里指定了一个-->
     <property name="locations"> <list> <value>file:/opt/config/config1.properties</value>
          <value>file:/opt/config/config2.properties</value>
</list> </property> <property name="ignoreUnresolvablePlaceholders" value="true"/> </bean> <dubbo:application name="lease-risk-consumer"/> <!-- 读取本地配置文件 --> <dubbo:registry address="${dubbo.registry.address}"/>

注意读取单个配置文件,使用location,多个使用locations

上面是介绍org.springframework.beans.factory.config.PropertyPlaceholderConfigurer工具类的具体使用,下面浅析Spring框架下PropertyPlaceholderConfigurer类

package org.springframework.beans.factory.config;

import java.util.Properties;
import java.util.Set;

import org.springframework.beans.BeansException;
import org.springframework.core.Constants;
import org.springframework.util.PropertyPlaceholderHelper;
import org.springframework.util.PropertyPlaceholderHelper.PlaceholderResolver;
import org.springframework.util.StringValueResolver;

public class PropertyPlaceholderConfigurer extends PlaceholderConfigurerSupport {

    /** 是否覆盖proprties文件 */
    public static final int SYSTEM_PROPERTIES_MODE_NEVER = 0;

    /**
     * 默认值,不存在时覆盖
     */
    public static final int SYSTEM_PROPERTIES_MODE_FALLBACK = 1;

    /**覆盖proprties文件*/
    public static final int SYSTEM_PROPERTIES_MODE_OVERRIDE = 2;


    private static final Constants constants = new Constants(PropertyPlaceholderConfigurer.class);

    private int systemPropertiesMode = SYSTEM_PROPERTIES_MODE_FALLBACK;

    private boolean searchSystemEnvironment = true;


    public void setSystemPropertiesModeName(String constantName) throws IllegalArgumentException {
        this.systemPropertiesMode = constants.asNumber(constantName).intValue();
    }
   
    public void setSystemPropertiesMode(int systemPropertiesMode) {
        this.systemPropertiesMode = systemPropertiesMode;
    }

    public void setSearchSystemEnvironment(boolean searchSystemEnvironment) {
        this.searchSystemEnvironment = searchSystemEnvironment;
    }
   
    protected String resolvePlaceholder(String placeholder, Properties props, int systemPropertiesMode) {
        String propVal = null;
        if (systemPropertiesMode == SYSTEM_PROPERTIES_MODE_OVERRIDE) {
            propVal = resolveSystemProperty(placeholder);
        }
        if (propVal == null) {
            propVal = resolvePlaceholder(placeholder, props);
        }
        if (propVal == null && systemPropertiesMode == SYSTEM_PROPERTIES_MODE_FALLBACK) {
            propVal = resolveSystemProperty(placeholder);
        }
        return propVal;
    }
  
    protected String resolvePlaceholder(String placeholder, Properties props) {
        return props.getProperty(placeholder);
    }
  
    protected String resolveSystemProperty(String key) {
        try {
            String value = System.getProperty(key);
            if (value == null && this.searchSystemEnvironment) {
                value = System.getenv(key);
            }
            return value;
        }
        catch (Throwable ex) {
            if (logger.isDebugEnabled()) {
                logger.debug("Could not access system property ‘" + key + "‘: " + ex);
            }
            return null;
        }
    }


    @Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
            throws BeansException {

        StringValueResolver valueResolver = new PlaceholderResolvingStringValueResolver(props);

        this.doProcessProperties(beanFactoryToProcess, valueResolver);
    }
   
    @Deprecated
    protected String parseStringValue(String strVal, Properties props, Set<?> visitedPlaceholders) {
        PropertyPlaceholderHelper helper = new PropertyPlaceholderHelper(
                placeholderPrefix, placeholderSuffix, valueSeparator, ignoreUnresolvablePlaceholders);
        PlaceholderResolver resolver = new PropertyPlaceholderConfigurerResolver(props);
        return helper.replacePlaceholders(strVal, resolver);
    }


    private class PlaceholderResolvingStringValueResolver implements StringValueResolver {

        private final PropertyPlaceholderHelper helper;

        private final PlaceholderResolver resolver;

        public PlaceholderResolvingStringValueResolver(Properties props) {
            this.helper = new PropertyPlaceholderHelper(
                    placeholderPrefix, placeholderSuffix, valueSeparator, ignoreUnresolvablePlaceholders);
            this.resolver = new PropertyPlaceholderConfigurerResolver(props);
        }

        public String resolveStringValue(String strVal) throws BeansException {
            String value = this.helper.replacePlaceholders(strVal, this.resolver);
            return (value.equals(nullValue) ? null : value);
        }
    }


    private class PropertyPlaceholderConfigurerResolver implements PlaceholderResolver {

        private final Properties props;

        private PropertyPlaceholderConfigurerResolver(Properties props) {
            this.props = props;
        }

        public String resolvePlaceholder(String placeholderName) {
            return PropertyPlaceholderConfigurer.this.resolvePlaceholder(placeholderName, props, systemPropertiesMode);
        }
    }

}

 

首先看下PropertyPlaceholderConfigurer类的结构

技术分享

1、注入会初始化property的location属性

 

public void setLocation(Resource location) {
    this.locations = new Resource[] {location};
}

public void setLocations(Resource[] locations) {
    this.locations = locations;
}

 


2、SystemPropertiesModeName:SystemPropertiesModeName属性用来指定系统变量(System.getProperty)是否覆盖proprties文件。默认是在配置文件里找不到时使用。三个选项分别是:

 

  SYSTEM_PROPERTIES_MODE_NEVER(不覆盖)

  SYSTEM_PROPERTIES_MODE_FALLBACK(默认值,不存在时覆盖)

  SYSTEM_PROPERTIES_MODE_OVERRIDE(覆盖)

  从源码中可以看出searchSystemEnvironment属性的默认值为true,即允许环境变量覆盖properties中的值。

springmvc加载xml文件读取本地properties配置文件

标签:

原文地址:http://www.cnblogs.com/yantz/p/4582811.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!