Map的三种遍历方式：

//创建Map对象
HashMap<String,String> setting = new HashMap<String,String>();
				
//添加键值
setting.put("username","root");
setting.put("passwprd",	"123456");
setting.put("ip", "192.168.0.1");
setting.put("port","1521");
setting.put("sid","orcl");
		
//根据键的名字获取对应的值
String ips = setting.get("ip");
System.out.println(ips);
				
//判断是否包含key
System.out.println(setting.containsKey("username")+" ");
//判断是否包含value
System.out.println(setting.containsKey("orcl"));
//获取键值的对个数
System.out.println(setting.size());
//把keySet()的集合视图给set集合。     set  是不包含重复元素的集合。
Set<String> keys = setting.keySet();
//for-each遍历map
for(String key:keys) {					                      System.out.println("key="+key+",value="+setting.get(key));
}
Iterator<String> it=keys.iterator();
while(it.hasNext()) {
String key = it.next();
System.out.println("key="+key+",value="+setting.get(key));
}
				
Set<Entry<String,String>> entrys = setting.entrySet();
Iterator<Entry<String,String>> its = entrys.iterator();
while(its.hasNext()) {
Entry<String,String> entry = its.next();
System.out.println("key="+entry.getKey()+",value="+entry.getValue());
}