Java 集合中存在多种数据类型

秒速五厘米 2023-05-22 10:26 10阅读 0赞

##### 我们想要在同一个集合中放入不同的数据类型，请看如下代码 #####

**完整代码**

import java.util.Map;
    import java.util.Set;
    import java.util.SortedMap;
    import java.util.SortedSet;
    import java.util.TreeMap;
    import java.util.TreeSet;
     
    import java.util.ArrayList;
    import java.util.Collection;
    import java.util.HashMap;
    import java.util.HashSet;
    import java.util.Iterator;
    import java.util.LinkedHashMap;
    import java.util.LinkedHashSet;
    import java.util.LinkedList;
    import java.util.List;
     
     
    public class Main { 
       public static void main(String[] args) { 
          List lnkLst = new LinkedList();
          lnkLst.add("num1");
          lnkLst.add("num2");
          lnkLst.add("num3");
          lnkLst.add("num4");
          displayAll(lnkLst);
          List aryLst = new ArrayList();
          aryLst.add("h");
          aryLst.add("a");
          aryLst.add("n");
          aryLst.add("g");
          displayAll(aryLst);
          Set hashSet = new HashSet();
          hashSet.add("set1");
          hashSet.add("set2");
          hashSet.add("set3");
          hashSet.add("set4");
          displayAll(hashSet);
          SortedSet treeSet = new TreeSet();
          treeSet.add("1");
          treeSet.add("2");
          treeSet.add("3");
          treeSet.add("4");
          displayAll(treeSet);
          LinkedHashSet lnkHashset = new LinkedHashSet();
          lnkHashset.add("one");
          lnkHashset.add("two");
          lnkHashset.add("three");
          lnkHashset.add("four");
          displayAll(lnkHashset);
          Map map1 = new HashMap();
          map1.put("key1", "J");
          map1.put("key2", "K");
          map1.put("key3", "L");
          map1.put("key4", "M");
          displayAll(map1.keySet());
          displayAll(map1.values());
          SortedMap map2 = new TreeMap();
          map2.put("key1", "ab");
          map2.put("key2", "cd");
          map2.put("key3", "ef");
          map2.put("key4", "gh");
          displayAll(map2.keySet());
          displayAll(map2.values());
          LinkedHashMap map3 = new LinkedHashMap();
          map3.put("key1", "aaa");
          map3.put("key2", "bbb");
          map3.put("key3", "ccc");
          map3.put("key4", "ddd");
          displayAll(map3.keySet());
          displayAll(map3.values());
       }
       static void displayAll(Collection col) { 
          Iterator itr = col.iterator();
          while (itr.hasNext()) { 
             String str = (String) itr.next();
             System.out.print(str + " ");
          }
          System.out.println();
       }
    }

结果输出

num1 num2 num3 num4
    h  a  n  g
    set3 set2 set4 set1 
    1 2 3 4 
    one two three four 
    key1 key2 key3 key4 
    J K L M 
    key1 key2 key3 key4 
     ab   cd   ef   gh
    key1 key2 key3 key4 
    aaa   bbb ccc  ddd