map集合的遍历

直接上代码：

package linruozhuo;import java.util.HashMap;import java.util.Iterator;import java.util.Map;public class JavaJihe {    public static void main(String[] args) {        Map<String ,String > map1 = new HashMap<String ,String >();        map1.put("1", "小米");        map1.put("2", "小红");        map1.put("3", "小明");        map1.put("4", "小华");        //通过键找值遍历（效率低）        System.out.println("通过Map.keySet遍历key和value：");          for (String key : map1.keySet()) {           System.out.println("key= "+ key + " and value= " + map1.get(key));          }        // Iterator遍历        System.out.println("通过Iterator遍历key和value：");        Iterator<Map.Entry<String,String >> entries = map1.entrySet().iterator();        while (entries.hasNext()) {              Map.Entry<String,String > entry = entries.next();              System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());          }          //foreach分别遍历key和value        System.out.println("foreach分别遍历key和value：");        for (String key : map1.keySet()) {            System.out.println("key= "+ key);        }        for (String value : map1.values()) {            System.out.println("value= "+ value);        }          //for循环        System.out.println("for遍历key和value：");        for (int i = 1; i <= map1.size(); i++) {            String key = i+"";             System.out.println("key= "+ (i) + " and value= " + map1.get(key));        }      }}