遍历HashMap的方法

来源：互联网发布：如何安装网络监控编辑：程序博客网时间：2024/05/01 21:46
import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Set; //循环遍历map的方法public class CircleMap {public static void main(String[] args) {   Map<String, Integer> tempMap = new HashMap<String, Integer>();   tempMap.put("a", 1);   tempMap.put("b", 2);   tempMap.put("c", 3);   // JDK1.4中   // 遍历方法一 hashmap entrySet() 遍历   System.out.println("方法一");   Iterator it = tempMap.entrySet().iterator();   while (it.hasNext()) {    Map.Entry entry = (Map.Entry) it.next();    Object key = entry.getKey();    Object value = entry.getValue();    System.out.println("key=" + key + " value=" + value);   }   System.out.println("");   // JDK1.5中,应用新特性For-Each循环   // 遍历方法二   System.out.println("方法二");   for (Map.Entry<String, Integer> entry : tempMap.entrySet()) {    String key = entry.getKey().toString();    String value = entry.getValue().toString();    System.out.println("key=" + key + " value=" + value);   }   System.out.println("");    // 遍历方法三 hashmap keySet() 遍历   System.out.println("方法三");   for (Iterator i = tempMap.keySet().iterator(); i.hasNext();) {    Object obj = i.next();    System.out.println(obj);// 循环输出key    System.out.println("key=" + obj + " value=" + tempMap.get(obj));   }   for (Iterator i = tempMap.values().iterator(); i.hasNext();) {    Object obj = i.next();    System.out.println(obj);// 循环输出value   }   System.out.println("");    // 遍历方法四 treemap keySet()遍历   System.out.println("方法四");   for (Object o : tempMap.keySet()) {    System.out.println("key=" + o + " value=" + tempMap.get(o));   }   System.out.println("11111");    // java如何遍历Map <String, ArrayList> map = new HashMap <String,   // ArrayList>();   System.out     .println("java 遍历Map <String, ArrayList> map = new HashMap <String, ArrayList>();");   Map<String, ArrayList> map = new HashMap<String, ArrayList>();   Set<String> keys = map.keySet();   Iterator<String> iterator = keys.iterator();   while (iterator.hasNext()) {    String key = iterator.next();    ArrayList arrayList = map.get(key);    for (Object o : arrayList) {     System.out.println(o + "遍历过程");    }   }   System.out.println("2222");   Map<String, List> mapList = new HashMap<String, List>();   for (Map.Entry entry : mapList.entrySet()) {    String key = entry.getKey().toString();    List<String> values = (List) entry.getValue();    for (String value : values) {     System.out.println(key + " --> " + value);    }   }}}
0 0