There are 100 keys and values in HashMap.how to get the keys
and values?
Below given are 4 ways to traverse a map.
You can use entrySet or KeySet to get the keys.Then loop over these keys using iterator or for loop to get the corresponding values.
import static java.net.HttpURLConnection.*;
import java.util.*;
public class MapTest {
public static void main(String... args) {
traverseMap();
}
private static void traverseMap() {
Map<Integer, String> data = new HashMap<Integer, String>();
data.put(HTTP_OK, "HTTP_OK");
data.put(HTTP_FORBIDDEN, "HTTP_FORBIDDEN");
data.put(HTTP_NOT_FOUND, "HTTP_NOT_FOUND");
System.out.printf("%nUsing JDK 5 foreach and entry set:%n");
Set<Map.Entry<Integer, String>> entries = data.entrySet();
for(Map.Entry<Integer, String> entry : entries) {
Integer key = entry.getKey();
String value = entry.getValue();
System.out.printf("%s = %s%n", key, value);
}
System.out.printf("%nUsing Iterator<Map.Entry> and entry set:%n");
for(Iterator<Map.Entry<Integer, String>> it = entries.iterator(); it.hasNext();) {
Map.Entry<Integer, String> entry = it.next();
Integer key = entry.getKey();
String value = entry.getValue();
System.out.printf("%s = %s%n", key, value);
}
System.out.printf("%nUsing JDK 5 foreach and key set:%n");
for(Integer key : data.keySet()) {
String value = data.get(key);
System.out.printf("%s = %s%n", key, value);
}
System.out.printf("%nUsing traditional Iterator and key set%n");
for(Iterator<Integer> it = data.keySet().iterator(); it.hasNext();) {
Integer key = it.next();
String value = data.get(key);
System.out.printf("%s = %s%n", key, value);
}
}
}
Source:http://javahowto.blogspot.in/2006/06/4-ways-to-traverse-map.html
Is This Answer Correct ? | 12 Yes | 0 No |
What are the types of methods in java?
What is integer valueof?
Is it necessary for the port addresses to be unique? Explain with reason.
What is a superclass?
what is life cycle of applet?
Which is better list or arraylist in java?
What is array size in java?
A non-static inner class may have object instances that are associated with instances of the class’s outer class. A static inner class does not have any object instances.
how you will prevent method overriding?
What Is Resource Leak?
What is the difference between throw and throws?
What is hash table in java?