重拾编程之路--map遍历的四种方式

map的遍历主要有两种方式：

1）通过for循环；

2）通过迭代器Iterator遍历；

package com.lulu.leetcode;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

public class C_mapIterator {
public Map<String, Integer> create(int n){
Map<String,Integer> map=new HashMap<String, Integer>();
for(int i=0;i<n;i++){
map.put(i+"", i);
}
return map;

}

public void IterMap1(Map<String, Integer> map){
System.out.println("IterMap1");
Iterator<String> iterator=map.keySet().iterator();
while(iterator.hasNext()){
String key=iterator.next();
Integer value=map.get(key);
System.out.println("key="+key+",value="+value);

}

}

public void IterMap2(Map<String, Integer> map){
System.out.println("IterMap2");
for(String key:map.keySet()){
Integer value=map.get(key);
System.out.println("key="+key+",value="+value);
}
}

public void IterMap3(Map<String, Integer> map){
System.out.println("IterMap3");
Iterator<Entry<String, Integer>> iterator=map.entrySet().iterator();
Entry<String, Integer> entry;
while(iterator.hasNext()){
entry=iterator.next();
String key=entry.getKey();
Integer value=entry.getValue();
System.out.println("key="+key+",value="+value);
}

}

public void IterMap4(Map<String, Integer> map){
System.out.println("IterMap4");
for(Entry<String, Integer> entry:map.entrySet()){
String key=entry.getKey();
Integer value=entry.getValue();
System.out.println("key="+key+",value="+value);
}
}

/**
* @param args
*/
public static void main(String[] args) {
C_mapIterator cMapIterator=new C_mapIterator();
Map<String, Integer>map=cMapIterator.create(5);
cMapIterator.IterMap1(map);
cMapIterator.IterMap2(map);
cMapIterator.IterMap3(map);
cMapIterator.IterMap4(map);

// TODO Auto-generated method stub

}

}