Map

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class TraversalMap {
public static void main(String[] args) {
Map<String, String> map = new HashMap<String, String>();
map.put("username", "qq");
map.put("password", "123");
map.put("userID", "1");
map.put("email", "qq@qq.com");

forMap(map);
System.out.println("--------------");
iteratorMap(map);
System.out.println("--------------");
keySetMap(map);
System.out.println("--------------");
entrySetMap(map);
}
//entrySet()
private static void entrySetMap(Map<String, String> map) {
Iterator it = map.entrySet().iterator();
// System.out.println(map.entrySet().size());
String key;
String value;
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
key = entry.getKey().toString();
value = entry.getValue().toString();
System.out.println(key + "====>" + value);
}
}
//keySet()
private static void keySetMap(Map<String, String> map) {
Iterator it = map.keySet().iterator();
while (it.hasNext()) {
String key;
String value;
key = it.next().toString();
value = map.get(key);
System.out.println(key + "--" + value);
}
}
//iterator
private static void iteratorMap(Map<String, String> map) {
Set set = map.entrySet();
Iterator i = set.iterator();
while (i.hasNext()) {
Map.Entry<String, String> entry = (Map.Entry<String, String>) i
.next();
System.out.println(entry.getKey() + "==" + entry.getValue());
}
}
//for
private static void forMap(Map<String, String> map) {
for (Map.Entry<String, String> entry : map.entrySet()) {
System.out.println(entry.getKey() + "--->" + entry.getValue());
}

}

}