单例模式读取配置文件只创建一次

package com.jy.modules.util;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.lang.StringUtils;
/**
*
* @description  功能描述:
* @author            作        者: zhouzhiwei
* @param                   参         数: 单例模式读取配置文件只创建一次
* @createdate   建立日期： 2015年6月9日下午5:55:35
* @projectname  项目名称: cms
* @packageclass 包及类名: com.jy.modules.util.SystemConfigUtil.java
*/
public class SystemConfigUtil {

private static SystemConfigUtil systemConfigUtil = null;
private static Map<String, String> proMap = new HashMap<String, String>();

@SuppressWarnings("rawtypes")
private SystemConfigUtil() throws Exception {
InputStream is = null;
try {
Properties pro = new Properties();
is = getClass().getResourceAsStream("/filesystem.properties"); //默认在根目录下
pro.load(is);
Enumeration e = pro.propertyNames();
while (e.hasMoreElements()) {
Object object = (Object) e.nextElement();
String value = (String) pro.get(object);
proMap.put((String) object, value);
}
} catch (Exception e2) {
e2.printStackTrace();
} finally {
try {
is.close();
} catch (Exception e) {
e.printStackTrace();
}
}

}

public static Map<String, String> getproMap() {
return proMap;
}

public static SystemConfigUtil getInstance() throws Exception {
if (systemConfigUtil == null) {
systemConfigUtil = new SystemConfigUtil();
}
return null;

}

@SuppressWarnings("static-access")
public static String  getValue(String mapkey) throws Exception{
SystemConfigUtil m = SystemConfigUtil.getInstance();
Map map = m.getproMap();
if(StringUtils.isNotBlank(mapkey)){
String key = (String) map.get(mapkey);
return key;
}
return mapkey;
}

}