java 遍历map 方法集合五种的方法

来源：互联网发布：cnnic数据报告 2017 编辑：程序博客网时间：2024/04/29 14:25
package com.jackey.topic;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);   }  } }}
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java 遍历map 方法 集合 五种的方法

java 遍历map 方法集合五种的方法
