前言:
1.声明一个map: Map map = new HashMap();2.向map中放值,注意:map是key-value的形式存放的.如: map.put(”sa”,”dd”); 3.从map中取值:String str = map.get(”sa”).toString();结果是:str = ”dd”;4.遍历一个map,从中取得key 和valueMap map = new HashMap() ; Iterator it = map.entrySet().iterator() ;while (it.hasNext()){Map.Entry entry = (Map.Entry) it.next() ;Object key = entry.getKey() ;Object value = entry.getValue() ;}
Java代码如下:
package Test01; import java.util.HashMap; import java.util.Iterator; import java.util.Map; public class Test03 { public static void main(String[] args){ a(); b(); } @SuppressWarnings("unchecked") public static void a(){ @SuppressWarnings("rawtypes") Map map = new HashMap(); map.put("1","aa"); map.put("2","bb"); map.put("3","cc"); map.put("4","dd"); map.put("5","ee"); map.put("6","ff"); map.put("7","gg"); String str = map.get("5").toString(); System.out.println(str); } @SuppressWarnings("unchecked") public static void b(){ @SuppressWarnings("rawtypes") Map map = new HashMap(); map.put("1","aa"); map.put("2","bb"); map.put("3","cc"); map.put("4","dd"); map.put("5","ee"); map.put("6","ff"); map.put("7","gg"); @SuppressWarnings("rawtypes") Iterator it = map.entrySet().iterator() ; while (it.hasNext()) { @SuppressWarnings("rawtypes") Map.Entry entry = (Map.Entry) it.next() ; Object key = entry.getKey() ; Object value = entry.getValue() ; System.out.print("["+key+"、"); System.out.print(value+"]"); System.out.print(","); } } }
代码运行后效果如下:
时间: 2024-08-03 07:52:20