Summary of several looping methods in Java Map

According to the new features of JDK, use For to loop Map, such as looping the Key of Map

Java code

for(String dataKey : paraMap.keySet())    
{    
    System.out.println(dataKey );               
}

What should be noted here is how paraMap is defined. If it is a simple Map paraMap = new HashMap(); then The previous String can only be replaced with Object.

Loop through the key and value of the entire Map, as follows:

Java code

for(Map.Entry<String, Object> entry : paraMap.entrySet())    
{    
    System.out.println(entry.getKey()+": "+entry.getValue());    
}

In the past, it was looped like this:

java code

Iterator it = paraMap.entrySet().iterator();    
while (it.hasNext())     
{    
        Map.Entry pairs = (Map.Entry)it.next();    
        System.out.println(pairs.getKey() + " = " + pairs.getValue());    
 }

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