Java读取properties文件(非泛滥)

根据spring配置文件的 PropertiesFactoryBean和 PropertyPlaceholderConfigurer可以选择不同的加载方式，我是使用System.setProperty(key, value)，代码中可以直接用System.getProperty(key)取value的值

一、PropertyPlaceholderConfigurer

PropertyPlaceholderConfigurer是解决 properties 文件占位符问题，实现 PropertiesLoaderSupport 类

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
	<property name="locations">
		<list>
			<value>classpath:jdbc.properties</value>
			<value>classpath:redis.properties</value>
		</list>
	</property>
	<!-- 忽略不可解析的 -->
	<property name="ignoreUnresolvablePlaceholders" value="true" />
</bean>

package com.phil.common.prop;

import java.util.Map.Entry;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Component;

/**
 * 加载Properties文件
 * @author phil
 * @date 2017年8月13日
 *
 */
@Component
public class InitializingProperties implements InitializingBean {

	private static final Logger logger = Logger.getLogger(InitializingProperties.class);

	/*
	 * (non-Javadoc)
	 *
	 * @see
	 * org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
	 */
	@Override
	public void afterPropertiesSet() throws Exception {
		Properties props = new Properties();
		props.load(InitializingProperties.class.getClassLoader().getResourceAsStream("test1.properties"));
		props.load(InitializingProperties.class.getClassLoader().getResourceAsStream("test2.properties"));
		for (Entry<Object, Object> e : props.entrySet()) {
			System.setProperty(e.getKey().toString(), e.getValue().toString());
			logger.info(e.getKey().toString() + "---" + e.getValue().toString());
		}
	}
}

二、PropertiesFactoryBean

PropertiesFactoryBean 是PropertiesLoaderSupport 直接的实现类

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
	<property name="location">
		<value>classpath:portal_dev.properties</value>
	</property>
</bean>

package com.phil.common.prop;

import java.util.Map.Entry;
import java.util.Properties;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * 加载Properties文件
 * @author phil
 * @date 2017年8月13日
 *
 */
@Component
public class InitializingProperties implements InitializingBean {

	private static final Logger logger = Logger.getLogger(InitializingProperties.class);

	@Autowired
	private Properties propertyConfigurer;

	/*
	 * (non-Javadoc)
	 *
	 * @see
	 * org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
	 */
	@Override
	public void afterPropertiesSet() throws Exception {
		for (Entry<Object, Object> e : propertyConfigurer.entrySet()) {
			System.setProperty(e.getKey().toString(), e.getValue().toString());
			logger.info(e.getKey().toString() + "---" + e.getValue().toString());
		}
	}
}