如何使用JAVA API中的Collection 來儲存值

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通常Vector裡的都是物件的reference,而不是實際的物件

存放在Vector裡的都是物件，所以才會有String和int...等等的資料型態的差異，

例如：String在JAVA裡事物件的型態，可是int...等等，都是數值，而不是物件

把一些物件塞入Vector, 例如:

 Vector v = new Vector();

Vector w = new Vector();

String[] firstnames = { "Spencer" , "Benx" , "Jaseph" , "Isao" , "Sidekick" };

String[] lastnames = { "is handsome boy" , "is our manager" , "is sale's father" , "is

tobacco's man" , "is our MIS"};



for( int i =0 ; i < firstnames.length ; i++ )

v.add(firstnames[i]);

for( int k =0 ; k < lastnames.length ; k++)

w.add(lastnames[k]);

for( int j = 0 ; j < v.size() ; j++)

System.out.println(" Odject.co's the best teammates = " + v.get(j) +" "+ w.get(j));

NEW起來一個Vector,然後跑一個for迴圈,把值塞入.

get出來時候,也是以同樣的方式

或者用Iterator來一一取得集合裡的值

Iterator it = v.iterator();

Iterator lit = w.iterator();



while(it.hasNext()){

System.out.println(" Odject.co's the best teammates(Iterators) = " + it.next()+" "+ lit.next());

}

以上面的結果,出來的值:

Odject.co's the best teammates = Spencer is handsome boy

Odject.co's the best teammates = Benx is our manager

Odject.co's the best teammates = Jaseph is sale's father

Odject.co's the best teammates = Isao is tobacco's man

Odject.co's the best teammates = Sidekick is our MIS

Odject.co's the best teammates(Iterators) = Spencer is handsome boy

Odject.co's the best teammates(Iterators) = Benx is our manager

Odject.co's the best teammates(Iterators) = Jaseph is sale's father

Odject.co's the best teammates(Iterators) = Isao is tobacco's man

Odject.co's the best teammates(Iterators) = Sidekick is our MIS

如果是一個陣列其元素是數值(只有字串是物件,塞入集合中只能塞入物件)時:

Vector a = new Vector();
int[] h = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 };
for( int g = 0 ; g < h.length ; g++ )
a.add( new Integer ( h[g] ));
Iterator lv = a.iterator();
while(lv.hasNext()){
System.out.println( " LV的(iterator) "+ lv.next());
}

雜湊表的用法學習：

//雜湊表的塞值和取值

HashMap aMap = new HashMap();

String myKey1 = "key1";

String myKey2 = "key2";

Integer theObject1 = new Integer(12345);

String theObject2 = "塞入的第二個值 theObject2";

aMap.put( myKey1 , theObject1);

aMap.put( myKey2 , theObject2);

if(aMap.put( myKey1 , theObject1) != null ){

System.out.println(" Oh Ya Baby ~~~~ I put an object to HashMap ");

}

System.out.println(aMap.get(myKey1));

System.out.println(aMap.get("key1"));

System.out.println(aMap.get("key2"));


雜湊表中用Iterator的塞key取值法：

Set keys = aMap.keySet();

Iterator keyIter = keys.iterator();

//Iterator keyIter = aMap.keySet().iterator();

while(keyIter.hasNext()){

System.out.println("aMap.Iterator(value) = " + keyIter.next());

}