Java 实例 - 集合中添加不同类型元素
以下实例演示了在集合类中添加不同类型的元素:
Main.java 文件
importjava.util.Map;
importjava.util.Set;
importjava.util.SortedMap;
importjava.util.SortedSet;
importjava.util.TreeMap;
importjava.util.TreeSet;
importjava.util.ArrayList;
importjava.util.Collection;
importjava.util.HashMap;
importjava.util.HashSet;
importjava.util.Iterator;
importjava.util.LinkedHashMap;
importjava.util.LinkedHashSet;
importjava.util.LinkedList;
importjava.util.List;
publicclassMain{publicstaticvoidmain(String[]args){ListlnkLst = newLinkedList();
lnkLst.add("element1");
lnkLst.add("element2");
lnkLst.add("element3");
lnkLst.add("element4");
displayAll(lnkLst);
ListaryLst = newArrayList();
aryLst.add("x");
aryLst.add("y");
aryLst.add("z");
aryLst.add("w");
displayAll(aryLst);
SethashSet = newHashSet();
hashSet.add("set1");
hashSet.add("set2");
hashSet.add("set3");
hashSet.add("set4");
displayAll(hashSet);
SortedSettreeSet = newTreeSet();
treeSet.add("1");
treeSet.add("2");
treeSet.add("3");
treeSet.add("4");
displayAll(treeSet);
LinkedHashSetlnkHashset = newLinkedHashSet();
lnkHashset.add("one");
lnkHashset.add("two");
lnkHashset.add("three");
lnkHashset.add("four");
displayAll(lnkHashset);
Mapmap1 = newHashMap();
map1.put("key1", "J");
map1.put("key2", "K");
map1.put("key3", "L");
map1.put("key4", "M");
displayAll(map1.keySet());
displayAll(map1.values());
SortedMapmap2 = newTreeMap();
map2.put("key1", "JJ");
map2.put("key2", "KK");
map2.put("key3", "LL");
map2.put("key4", "MM");
displayAll(map2.keySet());
displayAll(map2.values());
LinkedHashMapmap3 = newLinkedHashMap();
map3.put("key1", "JJJ");
map3.put("key2", "KKK");
map3.put("key3", "LLL");
map3.put("key4", "MMM");
displayAll(map3.keySet());
displayAll(map3.values());
}staticvoiddisplayAll(Collectioncol){Iteratoritr = col.iterator();
while(itr.hasNext()){Stringstr = (String)itr.next();
System.out.print(str + "");
}System.out.println();
}}
以上代码运行输出结果为:
element1 element2 element3 element4 x y z w set3 set2 set4 set1 1 2 3 4 one two three four key1 key2 key3 key4 J K L M key1 key2 key3 key4 JJ KK LL MM key1 key2 key3 key4 JJJ KKK LLL MMM