七种遍历Map的方法

七种遍历Map的方法

import java.util.HashMap; import java.util.Iterator; import java.util.Map;
public class Wan { public static void main(String[] args) { Map<String,String>
dataMap= new HashMap<>(); dataMap.put("A","Abb"); dataMap.put("B","Bcc");
dataMap.put("C","Cdd"); // 1. forEach+lambda dataMap.forEach((k,v)-> System.out.
println(k+"->"+v)); // 2. keySet+foreach for (String key: dataMap.keySet()){
System.out.println(key+"->"+dataMap.get(key)); } // 3. entry+stream dataMap.
entrySet().stream().forEach(entry -> System.out.println(entry.getKey()+"->"+
entry.getValue()) ); // 4. stream并行处理 dataMap.entrySet().stream().parallel().
forEach(entry -> System.out.println(entry.getKey()+"->"+entry.getValue()) ); //
5. foreach Map.EntrySet for (Map.Entry<String,String> item: dataMap.entrySet())
{ System.out.println(item.getKey()+"->"+item.getValue()); } // 6.迭代器+Map.Entry
Iterator<Map.Entry<String,String>> item2 = dataMap.entrySet().iterator(); while
(item2.hasNext()){ Map.Entry<String,String> next = item2.next(); System.out.
println(next.getKey()+"->"+next.getValue()); } // 7. keyset+迭代器 Iterator<String>
item3= dataMap.keySet().iterator(); while (item3.hasNext()){ String key = item3
.next(); System.out.println(key+"->"+dataMap.get(key)); } } }

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