小弟头一回用到hashmap,思路比较乱。
我现在有个嵌套的hashmap.里面的hashmap是:
Map map1 = new HashMap();
map1.put("hey1","val1");
map1.put("hey2","val2");
map1.put("hey3","val3");
map1.put("hey4","val4");
外面的hashmap:
Map map0 = new HashMap();
map0.put("0",map1);
map0.put("1",map1);现在我想取key2和key4的值,该怎么写。
我现在有个嵌套的hashmap.里面的hashmap是:
Map map1 = new HashMap();
map1.put("hey1","val1");
map1.put("hey2","val2");
map1.put("hey3","val3");
map1.put("hey4","val4");
外面的hashmap:
Map map0 = new HashMap();
map0.put("0",map1);
map0.put("1",map1);现在我想取key2和key4的值,该怎么写。
map0.get("0").get("key2");
或
map0.get("1").get("key2");
当然这里有可能需要强转一下
自动加了个(UIManager) 什么意思?
怎么强转?能细点说明吗?
Map <String, String>map1 = new HashMap<String, String>();
map1.put("hey1","val1");
map1.put("hey2","val2");
map1.put("hey3","val3");
map1.put("hey4","val4"); Map map0 = new HashMap();
map0.put("0",map1);
map0.put("1",map1);
HashMap hey2 = (HashMap)map0.get("0");
String resultHey2 = (String)hey2.get("hey2");
System.out.println("The value of the map is:" + resultHey2);
HashMap hey4 = (HashMap)map0.get("1");
String resultHey4 = (String)hey4.get("hey4");
System.out.println("The value of the map is:" + resultHey4);
自己写上就有x;
我就跟着错,
我并不清楚你这个程序是什么意思,因为map0中的两个EntrySet里都有map1,我就随便取一个:import java.util.HashMap;
import java.util.Map;public class Test {
public static void main(String[] args) {
Map<String, String> map1 = new HashMap<String, String>();
map1.put("hey1","val1");
map1.put("hey2","val2");
map1.put("hey3","val3");
map1.put("hey4","val4");
Map<String, Map<String, String>> map0 = new HashMap<String, Map<String, String>>();
map0.put("0",map1);
map0.put("1",map1);
System.out.println(map0.get("0").get("hey2"));
}
}
我外面hashmap的map0是这样写的:
Map map0 = new HashMap();
和Map<String, Map<String, String>> map0 = new HashMap<String, Map<String, String>>();
有点差距所一点不出来。
我是不是有点大头。谢谢各位指导。