Vector共有4個構(gòu)造函數(shù)
// 默認構(gòu)造函數(shù)
Vector()
// capacity是Vector的默認容量大小。當由于增加數(shù)據(jù)導致容量增加時，每次容量會增加一倍。
Vector(int capacity)
// capacity是Vector的默認容量大小，capacityIncrement是每次Vector容量增加時的增量值。
Vector(int capacity, int capacityIncrement)
// 創(chuàng)建一個包含collection的Vector
Vector(Collection<? extends E> collection) 

synchronized booleanadd(E object) void add(int location, E object)
synchronized booleanaddAll(Collection<? extends E> collection)
synchronized booleanaddAll(int location, Collection<? extends E> collection)
synchronized void addElement(E object)
synchronized intcapacity() void clear()
synchronized Object clone() booleancontains(Object object)
synchronized booleancontainsAll(Collection<?> collection)
synchronized void copyInto(Object[] elements)
synchronized EelementAt(int location) Enumeration<E> elements()
synchronized void ensureCapacity(int minimumCapacity)
synchronized booleanequals(Object object)
synchronized EfirstElement() Eget(int location)
synchronized inthashCode()
synchronized intindexOf(Object object, int location) intindexOf(Object object)
synchronized void insertElementAt(E object, int location)
synchronized booleanisEmpty()
synchronized ElastElement()
synchronized intlastIndexOf(Object object, int location)
synchronized intlastIndexOf(Object object)
synchronized Eremove(int location) booleanremove(Object object)
synchronized booleanremoveAll(Collection<?> collection)
synchronized void removeAllElements()
synchronized booleanremoveElement(Object object)
synchronized void removeElementAt(int location)
synchronized booleanretainAll(Collection<?> collection)
synchronized Eset(int location, E object)
synchronized void setElementAt(E object, int location)
synchronized void setSize(int length)
synchronized intsize()
synchronized List<E>subList(int start, int end)
synchronized <T> T[]toArray(T[] contents)
synchronized Object[] toArray()
synchronized String toString()
synchronized void trimToSize() 

java.lang.Object ? java.util.AbstractCollection<E> ? java.util.AbstractList<E> ? java.util.Vector<E>
public class Vector<E>extends AbstractList<E>implements List<E>, RandomAccess, Cloneable, java.io.Serializable {} 

package java.util;
public class Vector<E>extends AbstractList<E>implements List<E>, RandomAccess, Cloneable, java.io.Serializable
{ // 保存Vector中數(shù)據(jù)的數(shù)組protected Object[] elementData;// 實際數(shù)據(jù)的數(shù)量protected int elementCount;// 容量增長系數(shù)protected int capacityIncrement;// Vector的序列版本號private static final long serialVersionUID = -2767605614048989439L;// Vector構(gòu)造函數(shù)。默認容量是10。public Vector() {this(10);}// 指定Vector容量大小的構(gòu)造函數(shù)public Vector(int initialCapacity) {this(initialCapacity, 0);}// 指定Vector"容量大小"和"增長系數(shù)"的構(gòu)造函數(shù)public Vector(int initialCapacity, int capacityIncrement) {super();if (initialCapacity < 0)throw new IllegalArgumentException("Illegal Capacity: "+ initialCapacity);// 新建一個數(shù)組，數(shù)組容量是initialCapacitythis.elementData = new Object[initialCapacity];// 設(shè)置容量增長系數(shù)this.capacityIncrement = capacityIncrement;}// 指定集合的Vector構(gòu)造函數(shù)。public Vector(Collection<? extends E> c) {// 獲取“集合(c)”的數(shù)組，并將其賦值給elementDataelementData = c.toArray();// 設(shè)置數(shù)組長度elementCount = elementData.length;// c.toArray might (incorrectly) not return Object[] (see 6260652)if (elementData.getClass() != Object[].class)elementData = Arrays.copyOf(elementData, elementCount, Object[].class);}// 將數(shù)組Vector的全部元素都拷貝到數(shù)組anArray中public synchronized void copyInto(Object[] anArray) {System.arraycopy(elementData, 0, anArray, 0, elementCount);}// 將當前容量值設(shè)為 =實際元素個數(shù)public synchronized void trimToSize() {modCount++;int oldCapacity = elementData.length;if (elementCount < oldCapacity) {elementData = Arrays.copyOf(elementData, elementCount);}}// 確認“Vector容量”的幫助函數(shù)private void ensureCapacityHelper(int minCapacity) {int oldCapacity = elementData.length;// 當Vector的容量不足以容納當前的全部元素，增加容量大小。// 若 容量增量系數(shù)>0(即capacityIncrement>0)，則將容量增大當capacityIncrement// 否則，將容量增大一倍。if (minCapacity > oldCapacity) {Object[] oldData = elementData;int newCapacity = (capacityIncrement > 0) ?(oldCapacity + capacityIncrement) : (oldCapacity * 2);if (newCapacity < minCapacity) {newCapacity = minCapacity;}elementData = Arrays.copyOf(elementData, newCapacity);}}// 確定Vector的容量。public synchronized void ensureCapacity(int minCapacity) {// 將Vector的改變統(tǒng)計數(shù)+1modCount++;ensureCapacityHelper(minCapacity);}// 設(shè)置容量值為 newSizepublic synchronized void setSize(int newSize) {modCount++;if (newSize > elementCount) {// 若 "newSize 大于 Vector容量"，則調(diào)整Vector的大小。ensureCapacityHelper(newSize);} else {// 若 "newSize 小于/等于 Vector容量"，則將newSize位置開始的元素都設(shè)置為nullfor (int i = newSize ; i < elementCount ; i++) {elementData[i] = null;}}elementCount = newSize;}// 返回“Vector的總的容量”public synchronized int capacity() {return elementData.length;}// 返回“Vector的實際大小”，即Vector中元素個數(shù)public synchronized int size() {return elementCount;}// 判斷Vector是否為空public synchronized boolean isEmpty() {return elementCount == 0;}// 返回“Vector中全部元素對應(yīng)的Enumeration”public Enumeration<E> elements() {// 通過匿名類實現(xiàn)Enumerationreturn new Enumeration<E>() {int count = 0;// 是否存在下一個元素public boolean hasMoreElements() {return count < elementCount;}// 獲取下一個元素public E nextElement() {synchronized (Vector.this) {if (count < elementCount) {return (E)elementData[count++];}}throw new NoSuchElementException("Vector Enumeration");}};}// 返回Vector中是否包含對象(o)public boolean contains(Object o) {return indexOf(o, 0) >= 0;}// 從index位置開始向后查找元素(o)。// 若找到，則返回元素的索引值；否則，返回-1public synchronized int indexOf(Object o, int index) {if (o == null) {// 若查找元素為null，則正向找出null元素，并返回它對應(yīng)的序號for (int i = index ; i < elementCount ; i++)if (elementData[i]==null)return i;} else {// 若查找元素不為null，則正向找出該元素，并返回它對應(yīng)的序號for (int i = index ; i < elementCount ; i++)if (o.equals(elementData[i]))return i;}return -1;}// 查找并返回元素(o)在Vector中的索引值public int indexOf(Object o) {return indexOf(o, 0);}// 從后向前查找元素(o)。并返回元素的索引public synchronized int lastIndexOf(Object o) {return lastIndexOf(o, elementCount-1);}// 從后向前查找元素(o)。開始位置是從前向后的第index個數(shù)；// 若找到，則返回元素的“索引值”；否則，返回-1。public synchronized int lastIndexOf(Object o, int index) {if (index >= elementCount)throw new IndexOutOfBoundsException(index + " >= "+ elementCount);if (o == null) {// 若查找元素為null，則反向找出null元素，并返回它對應(yīng)的序號for (int i = index; i >= 0; i--)if (elementData[i]==null)return i;} else {// 若查找元素不為null，則反向找出該元素，并返回它對應(yīng)的序號for (int i = index; i >= 0; i--)if (o.equals(elementData[i]))return i;}return -1;}// 返回Vector中index位置的元素。// 若index月結(jié)，則拋出異常public synchronized E elementAt(int index) {if (index >= elementCount) {throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);}return (E)elementData[index];}// 獲取Vector中的第一個元素。// 若失敗，則拋出異常！public synchronized E firstElement() {if (elementCount == 0) {throw new NoSuchElementException();}return (E)elementData[0];}// 獲取Vector中的最后一個元素。// 若失敗，則拋出異常！public synchronized E lastElement() {if (elementCount == 0) {throw new NoSuchElementException();}return (E)elementData[elementCount - 1];}// 設(shè)置index位置的元素值為objpublic synchronized void setElementAt(E obj, int index) {if (index >= elementCount) {throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);}elementData[index] = obj;}// 刪除index位置的元素public synchronized void removeElementAt(int index) {modCount++;if (index >= elementCount) {throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount);} else if (index < 0) {throw new ArrayIndexOutOfBoundsException(index);}int j = elementCount - index - 1;if (j > 0) {System.arraycopy(elementData, index + 1, elementData, index, j);}elementCount--;elementData[elementCount] = null; /* to let gc do its work */}// 在index位置處插入元素(obj)public synchronized void insertElementAt(E obj, int index) {modCount++;if (index > elementCount) {throw new ArrayIndexOutOfBoundsException(index + " > " + elementCount);}ensureCapacityHelper(elementCount + 1);System.arraycopy(elementData, index, elementData, index + 1, elementCount - index);elementData[index] = obj;elementCount++;}// 將“元素obj”添加到Vector末尾public synchronized void addElement(E obj) {modCount++;ensureCapacityHelper(elementCount + 1);elementData[elementCount++] = obj;}// 在Vector中查找并刪除元素obj。// 成功的話，返回true；否則，返回false。public synchronized boolean removeElement(Object obj) {modCount++;int i = indexOf(obj);if (i >= 0) {removeElementAt(i);return true;}return false;}// 刪除Vector中的全部元素public synchronized void removeAllElements() {modCount++;// 將Vector中的全部元素設(shè)為nullfor (int i = 0; i < elementCount; i++)elementData[i] = null;elementCount = 0;}// 克隆函數(shù)public synchronized Object clone() {try {Vector<E> v = (Vector<E>) super.clone();// 將當前Vector的全部元素拷貝到v中v.elementData = Arrays.copyOf(elementData, elementCount);v.modCount = 0;return v;} catch (CloneNotSupportedException e) {// this shouldn't happen, since we are Cloneablethrow new InternalError();}}// 返回Object數(shù)組public synchronized Object[] toArray() {return Arrays.copyOf(elementData, elementCount);}// 返回Vector的模板數(shù)組。所謂模板數(shù)組，即可以將T設(shè)為任意的數(shù)據(jù)類型public synchronized <T> T[] toArray(T[] a) {// 若數(shù)組a的大小 < Vector的元素個數(shù)；// 則新建一個T[]數(shù)組，數(shù)組大小是“Vector的元素個數(shù)”，并將“Vector”全部拷貝到新數(shù)組中if (a.length < elementCount)return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass());// 若數(shù)組a的大小 >= Vector的元素個數(shù)；// 則將Vector的全部元素都拷貝到數(shù)組a中。System.arraycopy(elementData, 0, a, 0, elementCount);if (a.length > elementCount)a[elementCount] = null;return a;}// 獲取index位置的元素public synchronized E get(int index) {if (index >= elementCount)throw new ArrayIndexOutOfBoundsException(index);return (E)elementData[index];}// 設(shè)置index位置的值為element。并返回index位置的原始值public synchronized E set(int index, E element) {if (index >= elementCount)throw new ArrayIndexOutOfBoundsException(index);Object oldValue = elementData[index];elementData[index] = element;return (E)oldValue;}// 將“元素e”添加到Vector最后。public synchronized boolean add(E e) {modCount++;ensureCapacityHelper(elementCount + 1);elementData[elementCount++] = e;return true;}// 刪除Vector中的元素opublic boolean remove(Object o) {return removeElement(o);}// 在index位置添加元素elementpublic void add(int index, E element) {insertElementAt(element, index);}// 刪除index位置的元素，并返回index位置的原始值public synchronized E remove(int index) {modCount++;if (index >= elementCount)throw new ArrayIndexOutOfBoundsException(index);Object oldValue = elementData[index];int numMoved = elementCount - index - 1;if (numMoved > 0)System.arraycopy(elementData, index+1, elementData, index, numMoved);elementData[--elementCount] = null; // Let gc do its workreturn (E)oldValue;}// 清空Vectorpublic void clear() {removeAllElements();}// 返回Vector是否包含集合cpublic synchronized boolean containsAll(Collection<?> c) {return super.containsAll(c);}// 將集合c添加到Vector中public synchronized boolean addAll(Collection<? extends E> c) {modCount++;Object[] a = c.toArray();int numNew = a.length;ensureCapacityHelper(elementCount + numNew);// 將集合c的全部元素拷貝到數(shù)組elementData中System.arraycopy(a, 0, elementData, elementCount, numNew);elementCount += numNew;return numNew != 0;}// 刪除集合c的全部元素public synchronized boolean removeAll(Collection<?> c) {return super.removeAll(c);}// 刪除“非集合c中的元素”public synchronized boolean retainAll(Collection<?> c){return super.retainAll(c);}// 從index位置開始，將集合c添加到Vector中public synchronized boolean addAll(int index, Collection<? extends E> c) {modCount++;if (index < 0 || index > elementCount)throw new ArrayIndexOutOfBoundsException(index);Object[] a = c.toArray();int numNew = a.length;ensureCapacityHelper(elementCount + numNew);int numMoved = elementCount - index;if (numMoved > 0)System.arraycopy(elementData, index, elementData, index + numNew, numMoved);System.arraycopy(a, 0, elementData, index, numNew);elementCount += numNew;return numNew != 0;}// 返回兩個對象是否相等public synchronized boolean equals(Object o) {return super.equals(o);}// 計算哈希值public synchronized int hashCode() {return super.hashCode();}// 調(diào)用父類的toString()public synchronized String toString() {return super.toString();}// 獲取Vector中fromIndex(包括)到toIndex(不包括)的子集public synchronized List<E> subList(int fromIndex, int toIndex) {return Collections.synchronizedList(super.subList(fromIndex, toIndex), this);}// 刪除Vector中fromIndex到toIndex的元素protected synchronized void removeRange(int fromIndex, int toIndex) {modCount++;int numMoved = elementCount - toIndex;System.arraycopy(elementData, toIndex, elementData, fromIndex, numMoved);// Let gc do its workint newElementCount = elementCount - (toIndex-fromIndex);while (elementCount != newElementCount)elementData[--elementCount] = null;}// java.io.Serializable的寫入函數(shù)private synchronized void writeObject(java.io.ObjectOutputStream s)throws java.io.IOException {s.defaultWriteObject();}
} 

Integer value = null;
int size = vec.size();
for (int i=0; i<size; i++) {value = (Integer)vec.get(i); 
} 

Integer value = null;
int size = vec.size();
for (int i=0; i<size; i++) {value = (Integer)vec.get(i); 
} 

Integer value = null;
for (Integer integ:vec) {value = integ;
} 

Integer value = null;
Enumeration enu = vec.elements();
while (enu.hasMoreElements()) {value = (Integer)enu.nextElement();
} 

import java.util.*;
/*
 * @desc Vector遍歷方式和效率的測試程序。
 *
 * @author skywang
 */
public class VectorRandomAccessTest {public static void main(String[] args) {Vector vec= new Vector();for (int i=0; i<100000; i++)vec.add(i);iteratorThroughRandomAccess(vec) ;iteratorThroughIterator(vec) ;iteratorThroughFor2(vec) ;iteratorThroughEnumeration(vec) ;}private static void isRandomAccessSupported(List list) {if (list instanceof RandomAccess) {System.out.println("RandomAccess implemented!");} else {System.out.println("RandomAccess not implemented!");}}public static void iteratorThroughRandomAccess(List list) {long startTime;long endTime;startTime = System.currentTimeMillis();for (int i=0; i<list.size(); i++) {list.get(i);}endTime = System.currentTimeMillis();long interval = endTime - startTime;System.out.println("iteratorThroughRandomAccess：" + interval+" ms");}public static void iteratorThroughIterator(List list) {long startTime;long endTime;startTime = System.currentTimeMillis();for(Iterator iter = list.iterator(); iter.hasNext(); ) {iter.next();}endTime = System.currentTimeMillis();long interval = endTime - startTime;System.out.println("iteratorThroughIterator：" + interval+" ms");}public static void iteratorThroughFor2(List list) {long startTime;long endTime;startTime = System.currentTimeMillis();for(Object obj:list);endTime = System.currentTimeMillis();long interval = endTime - startTime;System.out.println("iteratorThroughFor2：" + interval+" ms");}public static void iteratorThroughEnumeration(Vector vec) {long startTime;long endTime;startTime = System.currentTimeMillis();for(Enumeration enu = vec.elements(); enu.hasMoreElements(); ) {enu.nextElement();}endTime = System.currentTimeMillis();long interval = endTime - startTime;System.out.println("iteratorThroughEnumeration：" + interval+" ms");}
} 

import java.util.Vector;
import java.util.List;
import java.util.Iterator;
import java.util.Enumeration;
/**
 * @desc Vector測試函數(shù)：遍歷Vector和常用API 
 */
public class VectorTest {public static void main(String[] args) {// 新建VectorVector vec = new Vector();// 添加元素vec.add("1");vec.add("2");vec.add("3");vec.add("4");vec.add("5");// 設(shè)置第一個元素為100vec.set(0, "100");// 將“500”插入到第3個位置vec.add(2, "300");System.out.println("vec:"+vec);// (順序查找)獲取100的索引System.out.println("vec.indexOf(100):"+vec.indexOf("100"));// (倒序查找)獲取100的索引System.out.println("vec.lastIndexOf(100):"+vec.lastIndexOf("100"));// 獲取第一個元素System.out.println("vec.firstElement():"+vec.firstElement());// 獲取第3個元素System.out.println("vec.elementAt(2):"+vec.elementAt(2));// 獲取最后一個元素System.out.println("vec.lastElement():"+vec.lastElement());// 獲取Vector的大小System.out.println("size:"+vec.size());// 獲取Vector的總的容量System.out.println("capacity:"+vec.capacity());// 獲取vector的“第2”到“第4”個元素System.out.println("vec 2 to 4:"+vec.subList(1, 4));// 通過Enumeration遍歷VectorEnumeration enu = vec.elements();while(enu.hasMoreElements())System.out.println("nextElement():"+enu.nextElement());Vector retainVec = new Vector();retainVec.add("100");retainVec.add("300");// 獲取“vec”中包含在“retainVec中的元素”的集合System.out.println("vec.retain():"+vec.retainAll(retainVec));System.out.println("vec:"+vec);// 獲取vec對應(yīng)的String數(shù)組String[] arr = (String[]) vec.toArray(new String[0]);for (String str:arr)System.out.println("str:"+str);// 清空Vector。clear()和removeAllElements()一樣！vec.clear();
//vec.removeAllElements();// 判斷Vector是否為空System.out.println("vec.isEmpty():"+vec.isEmpty());} 
}