Several cycle modes of Map

Based on the new features of JDK, we use For loop Map, such as the Key of cyclic Map.
Java code
For (String dataKey: paraMap. keySet ())
{
System. out. println (dataKey );
}
 
Note how paraMap is defined. If it is a simple Map paraMap = new HashMap (), then the previous String can only be replaced with an Object.
Loop the keys and values of the entire Map, as follows:

Java code
For (Map. Entry <String, Object> entry: paraMap. entrySet ())
{
System. out. println (entry. getKey () + ":" + entry. getValue ());
}
 
If it was previously, it would be such a loop:
Java code
Java code
Iterator it = paraMap. entrySet (). iterator ();
While (it. hasNext ())
{
Map. Entry pairs = (Map. Entry) it. next ();
System. out. println (pairs. getKey () + "=" + pairs. getValue ());
}

 

This article is from "My strategy"