WEB购物车 核心详解

//循环遍历map的方法 public class CircleMap {

public static void main(String[] args) {

Map tempMap = new HashMap(); tempMap.put(\"a\ tempMap.put(\"b\ tempMap.put(\"c\ // 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 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 map = new HashMap (); System.out

.println(\"java 遍历Map map = new HashMap ();\");

Map map = new HashMap(); Set keys = map.keySet();

Iterator 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 mapList = new HashMap(); for (Map.Entry entry : mapList.entrySet()) { String key = entry.getKey().toString();

List values = (List) entry.getValue(); for (String value : values) {

System.out.println(key + \" --> \" + value); } } } }