JAVA 获取系统环境变量

分享代码：

 package com.base.entity;

 import java.io.Serializable;
 import java.util.Comparator;

 /**
  * 系统环境变量
  *
  * @author test
  * @create 2014-3-10下午04:35:47
  * @version 1.0
  */
 public class SystemProperty implements Serializable, Comparator {

     private static final long serialVersionUID = 1L;

     // 属性key
     private String iKey;

     // 属性Value
     private String iVal;

     public SystemProperty() {
         // TODO Auto-generated constructor stub
     }

     public SystemProperty(String iKey, String iVal) {
         super();
         this.iKey = iKey;
         this.iVal = iVal;
     }

     @Override
     public int compare(Object o1, Object o2) {
         // TODO Auto-generated method stub

         SystemProperty s1 = (SystemProperty) o1;
         SystemProperty s2 = (SystemProperty) o2;

         return s1.getiKey().compareTo(s2.getiKey());
     }

     public String getiKey() {
         return iKey;
     }

     public void setiKey(String iKey) {
         this.iKey = iKey;
     }

     public String getiVal() {
         return iVal;
     }

     public void setiVal(String iVal) {
         this.iVal = iVal;
     }
 }

 package com.util.common;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;

 import com.base.entity.SystemProperty;

 /**
  * @author test
  * @create 2014-3-10下午04:39:08
  * @version 1.0
  */
 public final class Read {

     /**
      * 获取系统所有环境变量
      *
      * @return List<SystemProperty>
      * @throws Exception
      */
     public static List<SystemProperty> readSysPropertyAll() throws Exception {
         return readSysProperty("BOCO_ALL");
     }

     /**
      * 获取系统指定环境变量
      *
      * @param key
      *            环境变量Key
      * @return List<SystemProperty>
      * @throws Exception
      */
     public static List<SystemProperty> readSysProperty(String key)
             throws Exception {

         List<SystemProperty> list = new ArrayList<SystemProperty>();

         Map m = System.getenv();
         String keys = "";
         if (key.equals("BOCO_ALL")) {
             for (Iterator<String> iter = m.keySet().iterator(); iter.hasNext();) {
                 keys = iter.next();
                 list.add(new SystemProperty(keys, m.get(keys).toString()));
                 Collections.sort(list, new SystemProperty());
             }
         } else {
             if (m.containsKey(key)) {
                 list.add(new SystemProperty(key, m.get(key).toString()));
             } else {
                 throw new Exception("系统中未包含指定Key：" + key);
             }
         }
         return list;
     }
 }