Map集合和List集合的几种遍历方式
2018-02-27 14:53
411 查看
++++++++++++++++++++++List集合遍历++++++++++++++++++++++++++++++++++++++++++++++
public static void main(String[] args) {
List<String> list=new ArrayList<String>();
list.add("123");
list.add("456");
list.add("789");
System.out.println("------经典的for循环-----");
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i));
}
System.out.println("-------Iterate循环--------");
Iterator<String> iter=list.iterator();
while(iter.hasNext())
{
System.out.println(iter.next());
}
System.out.println("-------foreach循环---------");
for (String string : list) {
System.out.println(string);
}
}
++++++++++++++++++++++MAP集合的遍历++++++++++++++++++++++++++++++++++++++++++++++
//循环遍历map的方法
public class MapF {
public static void main(String[] args) {
Map<String, Integer> tempMap = new HashMap<String, Integer>();
tempMap.put("a","12");
tempMap.put("b","34");
tempMap.put("c","56");
// JDK1.4中
// 遍历方法一 hashmap entrySet() 遍历
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
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
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
}
// 遍历方法四 treemap keySet()遍历
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);
}
}
Map<String, List> map = new HashMap<String, List>();
for (Map.Entry entry : map.entrySet()) {
String key = entry.getKey().toString();
List<String> list= (List) entry.getValue();
for (String value : list) {
System.out.println(key + "====" + value);
}
}
}
}
public static void main(String[] args) {
List<String> list=new ArrayList<String>();
list.add("123");
list.add("456");
list.add("789");
System.out.println("------经典的for循环-----");
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i));
}
System.out.println("-------Iterate循环--------");
Iterator<String> iter=list.iterator();
while(iter.hasNext())
{
System.out.println(iter.next());
}
System.out.println("-------foreach循环---------");
for (String string : list) {
System.out.println(string);
}
}
++++++++++++++++++++++MAP集合的遍历++++++++++++++++++++++++++++++++++++++++++++++
//循环遍历map的方法
public class MapF {
public static void main(String[] args) {
Map<String, Integer> tempMap = new HashMap<String, Integer>();
tempMap.put("a","12");
tempMap.put("b","34");
tempMap.put("c","56");
// JDK1.4中
// 遍历方法一 hashmap entrySet() 遍历
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
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
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
}
// 遍历方法四 treemap keySet()遍历
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);
}
}
Map<String, List> map = new HashMap<String, List>();
for (Map.Entry entry : map.entrySet()) {
String key = entry.getKey().toString();
List<String> list= (List) entry.getValue();
for (String value : list) {
System.out.println(key + "====" + value);
}
}
}
}
相关文章推荐
- java中List、Set、Map集合遍历的几种方式小结和比较
- 遍历List、Set、Map集合的几种方式
- Java中Map集合和List集合的遍历方式
- List及Map遍历的几种方式
- List和Map常用的几种遍历方式
- Set、List、Map的遍历的几种方式
- list和set集合的几种遍历方式
- 遍历集合List几种方式
- Map 和 List 各自遍历的几种方式
- think in java读后总结---Map集合的几种遍历方式
- 【Java】Map集合的几种遍历方式
- map集合的几种遍历方式
- 集合List、Set、Map的遍历方式
- Map集合中遍历的几种方式
- Map集合,List集合,Array数组,Iterator迭代,Collection集合,Set集合的多种遍历方式
- Java之List和Map的几种遍历方式
- java中list,set,Map集合的遍历方式
- map集合的遍历的几种方式
- Java种遍历Map集合的几种常用方式