|
|
以下实例演示了在集合类中添加元素： Main.java 文件 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<String> lnkLst = new LinkedList<String> ( ) ;
lnkLst . add ( " element1 " ) ;
lnkLst . add ( " element2 " ) ;
lnkLst . add ( " element3 " ) ;
lnkLst . add ( " element4 " ) ;
displayAll ( lnkLst ) ;
List<String> aryLst = new ArrayList<String> ( ) ;
aryLst . add ( " x " ) ;
aryLst . add ( " y " ) ;
aryLst . add ( " z " ) ;
aryLst . add ( " w " ) ;
displayAll ( aryLst ) ;
Set<String> hashSet = new HashSet<String> ( ) ;
hashSet . add ( " set1 " ) ;
hashSet . add ( " set2 " ) ;
hashSet . add ( " set3 " ) ;
hashSet . add ( " set4 " ) ;
displayAll ( hashSet ) ;
SortedSet<String> treeSet = new TreeSet <String>( ) ;
treeSet . add ( " 1 " ) ;
treeSet . add ( " 2 " ) ;
treeSet . add ( " 3 " ) ;
treeSet . add ( " 4 " ) ;
displayAll ( treeSet ) ;
LinkedHashSet<String> lnkHashset = new LinkedHashSet<String> ( ) ;
lnkHashset . add ( " one " ) ;
lnkHashset . add ( " two " ) ;
lnkHashset . add ( " three " ) ;
lnkHashset . add ( " four " ) ;
displayAll ( lnkHashset ) ;
Map<String,String> map1 = new HashMap <String,String>( ) ;
map1 . put ( " key1 " , " J " ) ;
map1 . put ( " key2 " , " K " ) ;
map1 . put ( " key3 " , " L " ) ;
map1 . put ( " key4 " , " M " ) ;
displayAll ( map1 . keySet ( ) ) ;
displayAll ( map1 . values ( ) ) ;
SortedMap<String,String> map2 = new TreeMap<String,String> ( ) ;
map2 . put ( " key1 " , " JJ " ) ;
map2 . put ( " key2 " , " KK " ) ;
map2 . put ( " key3 " , " LL " ) ;
map2 . put ( " key4 " , " MM " ) ;
displayAll ( map2 . keySet ( ) ) ;
displayAll ( map2 . values ( ) ) ;
LinkedHashMap<String,String> map3 = new LinkedHashMap <String,String>( ) ;
map3 . put ( " key1 " , " JJJ " ) ;
map3 . put ( " key2 " , " KKK " ) ;
map3 . put ( " key3 " , " LLL " ) ;
map3 . put ( " key4 " , " MMM " ) ;
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 ( ) ;
}
} |
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
程序猿的技术大观园：www.javathinker.net
[这个贴子最后由 flybird 在 2020-01-26 11:43:38 重新编辑]
|
|
Java技术网站 → 『 Java开发技术 』 → 『 Java编程技术专题 』 → Java入门实用代码： 集合中添加元素
消息
查看
搜索
好友
邮件
复制
引用
IP: 已设置保密