java常用容器用法实例(Hashtable,ArrayList,vector)

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Hashtable 的用法 

package usehashtable;  
  
import java.util.Enumeration;  
import java.util.Hashtable;  
  
/**  
*  
* @author Administrator  
*/  
public class UseHashtable {  
  
  //创建Hashtable 对象  
  Hashtable ht=new Hashtable();  
  public UseHashtable() {  
  }  
  public void setHash(){  
  ht.put("1","a");  
  ht.put("2","b");  
  ht.put("3","c");  
  }  
  public void getHash(){  
  
  //用key来标记hashtable中的索引  
  Enumeration key=ht.keys();  
  
  //allvalue标记hashtable中索引对应的值  
  Enumeration allvalue=ht.elements();  
  System.out.println("hashtable all keys:");  
  while(key.hasMoreElements())  
  {  
  String str=(String)key.nextElement();  
  String strv=(String)allvalue.nextElement();  
  System.out.println(str+" : "+strv);  
  }  
  if(ht.containsKey("1"))  
  System.out.println("has the value 1");  
  else  
  System.out.println("do not contain 1");  
  ht.remove("1");  
  System.out.println("after remove the value 1:");  
  if(ht.containsKey("1"))  
  System.out.println("has the value 1");  
  else  
  System.out.println("do not contain 1");  
  if(ht.contains("c"))  
  System.out.println("has the value c");  
  }  
  public static void main(String[] args){  
  UseHashtable hs=new UseHashtable();  
  hs.setHash();  
  hs.getHash();  
   
  }  
}  

 
Vector的用法

package usehashtable;  
import java.util.Vector;  
import java.util.Enumeration;  
/**  
*  
* @author Administrator  
*/  
public class UseVector {  
   
  Vector mainv=new Vector();  
  /** Creates a new instance of Vector */  
  public UseVector() {  
  }  
  public void setVector(){  
  
  //按照如下实例你可以存取数据库中一条记录里所有的字段值  
  Vector v1=new Vector();  
  v1.add("1");  
  v1.add("a");  
  v1.add("1a");  
  mainv.add(v1);  
  Vector v2=new Vector();  
  v2.add("2");  
  v2.add("b");  
  v2.add("2b");  
  mainv.add(v2);  
  Vector v3=new Vector();  
  v3.add("3");  
  v3.add("c");  
  v3.add("3c");  
  mainv.add(v3);  
  }  
  public void getVector(){  
  for(int i=0;i<3;i++)  
  {  
  for(int j=0;j<3;j++)  
  {  
  System.out.print(checkNull(i,j)+" ");  
  }  
  System.out.println("");  
  }  
   
  }  
  
  //只有值不为空时才返回他的值  
  public String checkNull(int row,int col)  
  {  
  try {  
  if(!((String)((Vector)mainv.elementAt(row)).elementAt(col)).trim().equals(null)){  
  return ((String)((Vector)mainv.elementAt(row)).elementAt(col));  
  }  
  else return "";  
  } catch(Exception e){  
  return "";  
  }  
  }  
  public static void main(String[] args){  
  UseVector uv=new UseVector();  
  uv.setVector();  
  uv.getVector();  
  }  
}  

 

ArrayList的用法(借助一个Book类)

public class Book {  
  private String bookName;  
  private int bookPrice;  
  /** Creates a new instance of Book */  
  public Book() {  
  }  
  
  public int getBookPrice() {  
  return bookPrice;  
  }  
  
  public void setBookPrice(int bookPrice) {  
  this.bookPrice = bookPrice;  
  }  
  
  public String getBookName() {  
  return bookName;  
  }  
  
  public void setBookName(String bookName) {  
  this.bookName = bookName;  
  }  
   
}  
  
//ArrayList  
  
package usehashtable;  
import java.util.ArrayList;  
import java.util.Iterator;  
/**  
*  
* @author Administrator  
*/  
public class UseArraylist {  
   
  ArrayList ay=new ArrayList();  
  /** Creates a new instance of UseArraylist */  
  public UseArraylist() {  
  }  
  public void setArray(){  
  Book bk1=new Book();  
  bk1.setBookName("java");  
  bk1.setBookPrice(13);  
  ay.add(0,bk1);  
  Book bk2=new Book();  
  bk2.setBookName("jsp");  
  bk2.setBookPrice(30);  
  ay.add(bk2);  
  Book bk3=new Book();  
  bk3.setBookName("j2ee");  
  bk3.setBookPrice(20);  
  ay.add(bk3);  
  }  
  public void getArray(){  
  Iterator i=ay.iterator();  
  while(i.hasNext()){  
  Book bk=(Book)i.next();  
  System.out.println(bk.getBookName()+" ,"+bk.getBookPrice());  
  }  
  }  
  public static void main(String[] args){  
  UseArraylist list=new UseArraylist();  
  list.setArray();  
  list.getArray();  
  }  
}