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import java.util.*;
public class iterator {
public static void main(String[] args) {
HashMap<String, Integer> hashmap = new HashMap<>();
hashmap.put("1", 1);
hashmap.put("2", 2);
Set keyset = hashmap.keySet();
Object[] keys = keyset.toArray();
System.out.println(keys.getClass());
}
}
import java.util.*;
public class iterator {
public static void main(String[] args) {
HashMap<String, Integer> hashmap = new HashMap<>();
hashmap.put("1", 1);
hashmap.put("2", 2);
Set<String> keyset = hashmap.keySet();
String[] keys = keyset.toArray(new String[0]);
System.out.println(keys.getClass());
}
}
Set keyset = hashmap.keySet();
String[] keys = (String[]) keyset.toArray();
[/quote]
我觉得你这么写肯定报了警告,没有利用好泛型,上面keyset直接是Set原始类型,下面直接强转
Set keyset = hashmap.keySet();
String[] keys = (String[]) keyset.toArray();
Set<String> keyset = hashmap.keySet();
String[] keys = new String[keyset.size()];
keyset.toArray(keys);