java HashMap 迴圈遍曆map的方法(轉)

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


//迴圈遍曆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
// 遍曆方法一 hashmap entrySet() 遍曆
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,應用新特性For-Each迴圈
// 遍曆方法二
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("");

// 遍曆方法三 hashmap keySet() 遍曆
System.out.println("方法三");
for (Iterator i = tempMap.keySet().iterator(); i.hasNext();) {
Object obj = i.next();
System.out.println(obj);// 迴圈輸出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);// 迴圈輸出value
}

System.out.println("");

// 遍曆方法四 treemap keySet()遍曆
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如何遍曆Map <String, ArrayList> map = new HashMap <String, ArrayList>();
System.out.println("java 遍曆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 + "遍曆過程");
}
}
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);
}
}
}
}