import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.util.Properties;

import org.apache.log4j.Logger;

public final class PropertyUtil {

private static Logger LOG = Logger.getLogger(PropertyUtil.class);

// 配置文件

private static Properties demoProps = new Properties();

// 单例模式

private static PropertyUtil instance = null;

private PropertyUtil() {

// user.dir为应用目录

String filePath = System.getProperty("user.dir") + File.separator

+ "WEB-INF" + File.separator + "classes" + File.separator

+ "resources" + File.separator;

LOG.info(filePath);

try {

File demoFile = new File(filePath + "demo.properties");

if (httpFile.exists()) {

demoProps.load(new FileInputStream(filePath

+ "demo.properties"));

}

} catch (IOException e) {

LOG.info("The Exception occured.", e);

}

}

public synchronized static PropertyUtil getInstance() {

if (null == instance) {

instance = new PropertyUtil();

}

return instance;

}

/**

* 获取参数值

*

* @param key

* properites的key值

* @param defValue

* 默认值

* @return

*/

public String getValues(String key, String defValue) {

String rtValue = null;

if (null == key) {

LOG.error("key is null");

} else {

rtValue = getPropertiesValue(key);

}

if (null == rtValue) {

LOG.warn("PropertyUtil.getValues return null, key is " + key);

rtValue = defValue;

}

LOG.info("PropertyUtil.getValues: key is " + key + "; Value is "

+ rtValue);

return rtValue;

}

/**

* 根据key值获取server.properties的值

*

* @param key

* @return

*/

private String getPropertiesValue(String key) {

String rtValue = demoProps.getProperty(key);

return rtValue;

}

}

原文：http://blog.51cto.com/jtech/2154081