201871010108-高文利《面向对象程序设计（java）》第十二周学习总结

//示例程序1
import java.util.Vector;
class Cat {
	 private int catNumber;
	 Cat(int i) {
		catNumber = i;
	}
	 void print() {
		System.out.println("Cat #" + catNumber);
	 }
}
public class Cats{
public static void main(String[] args){
       Vector<Cat> cats= new Vector<Cat>();
       for(int i=0; i<7; i++)
           cats.addElement(new Cat(i)); 
       for(int i=0; i<cats.size(); i++)
         (cats.elementAt(i)).print();
   }
}

//示例程序2
import java.util.*;
public class Stacks
{
   static String[] months={"金","银","铜","铁"};
   public static void main(String[] args){
      Stack<String> stk = new Stack<String> ();
      for(int i=0; i<months.length; i++)
          stk.push(months[i]);
      System.out.println(stk);
      System.out.println("element 2=" + stk.elementAt(2));
      while(!stk.empty())
          System.out.println(stk.pop());
  }
}

//示例程序3
import java.util.*;
class Counter {
	int i = 1;
	public String toString() {
		return Integer.toString(i);
	}
}

public class Statistics {
	public static void main(String[] args) {
		Hashtable ht = new Hashtable();
		for (int i = 0; i < 10000; i++) {//生成10000个随机数
			Integer r = new Integer((int) (Math.random() * 20));
    if(ht.containsKey(r))//确定 Hashtable 是否包含特定键。
              ((Counter)ht.get(r)).i++;//计算key的hash值,匹配直到找到相对应key的value,若没有找到返回null
          else     ht.put(r, new Counter());
}	
		System.out.println(ht);
	}
}

import java.util.*;

public class ArrayListDemo {
	public static void main(String[] argv) {
		ArrayList al = new ArrayList();
		// Add lots of elements to the ArrayList...
		al.add(new Integer(11));//添加元素
		al.add(new Integer(12));
		al.add(new Integer(13));
		al.add(new String("hello"));
		// First print them out using a for loop.
		System.out.println("Retrieving by index:");
		for (int i = 0; i < al.size(); i++) {
			System.out.println("Element " + i + " = " + al.get(i));
		}
	 }
}

import java.util.*;
public class LinkedListDemo {
    public static void main(String[] argv) {
        LinkedList l = new LinkedList();
        l.add(new Object());
        l.add("Hello");
        l.add("zhangsan");
        ListIterator li = l.listIterator(0);
        while (li.hasNext())//存在可访问的元素
            System.out.println(li.next());//返回将要访问的下一个元素
        if (l.indexOf("Hello") < 0)  //返回第一次出现的指定子字符串在此字符串中的索引 
            System.err.println("Lookup does not work");
        else
            System.err.println("Lookup works");
   }
}

package linkedList;

import java.util.*;

/**
 * This program demonstrates operations on linked lists.
 * @version 1.12 2018-04-10
 * @author Cay Horstmann
 */
public class LinkedListTest
{
   public static void main(String[] args)
   {
      var a = new LinkedList<String>();//创建链表
      a.add("Amy");
      a.add("Carl");
      a.add("Erica");

      var b = new LinkedList<String>();
      b.add("Bob");
      b.add("Doug");
      b.add("Frances");
      b.add("Gloria");

      // 把b中的元素合并到a中

      ListIterator<String> aIter = a.listIterator();
      Iterator<String> bIter = b.iterator();

      while (bIter.hasNext())
      {
         if (aIter.hasNext()) aIter.next();
         aIter.add(bIter.next());
      }

      System.out.println(a);

      // remove every second word from b

      bIter = b.iterator();
      while (bIter.hasNext())
      {
         bIter.next(); // skip one element
         if (bIter.hasNext())
         {
            bIter.next(); //返回下一个要访问的元素
            bIter.remove(); // 移出元素
         }
      }

      System.out.println(b);


      a.removeAll(b);//删除a中删除b中存在的所有元素

      System.out.println(a);
   }
}

import javax.swing.*;
public class SimpleFrameTest
{
   public static void main(String[] args)
   {
     JFrame  frame = new JFrame(); 
     frame.setBounds(0, 0,300, 200);//移动并重新设置组件大小
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//用户关闭这个框架时的响应动作
     frame.setVisible(true); //获取或设置Visible属性   ，组件可见
   }
}

package simpleFrame;

import java.awt.*;
import javax.swing.*;

/**
 * @version 1.34 2018-04-10
 * @author Cay Horstmann
 */
public class SimpleFrameTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() ->
         {
            var frame = new SimpleFrame();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
         });
   }
}

class SimpleFrame extends JFrame
{
   private static final int DEFAULT_WIDTH = 300;
   private static final int DEFAULT_HEIGHT = 200;

   public SimpleFrame()
   {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);//使用给定的宽度和高度，重新设置组件大小
   }
}

package sizedFrame;

import java.awt.*;
import javax.swing.*;

/**
 * @version 1.35 2018-04-10
 * @author Cay Horstmann
 */
public class SizedFrameTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() ->
         {
            var frame = new SizedFrame();
            frame.setTitle("SizedFrame");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
         });
   }
}

class SizedFrame extends JFrame
{
   public SizedFrame()
   {
      // get screen dimensions

      Toolkit kit = Toolkit.getDefaultToolkit();//调用Toolkit类的静态方法getDefaultToolkit得到一个Toolkit对象
      Dimension screenSize = kit.getScreenSize();//调用getScreenSize方法，以Dimension对象形式返回屏幕大小
      int screenHeight = screenSize.height;//屏幕高度
      int screenWidth = screenSize.width;//屏幕宽度

      // set frame width, height and let platform pick screen location

      setSize(screenWidth / 2, screenHeight / 2);//框架大小定义为取值的50%
      setLocationByPlatform(true);//告知窗口系统定位框架

      // set frame icon

      Image img = new ImageIcon("icon.gif").getImage();
      setIconImage(img); //图像设置为框架图标     
   }
}

package notHelloWorld;

import javax.swing.*;
import java.awt.*;

/**
 * @version 1.34 2018-04-10
 * @author Cay Horstmann
 */
public class NotHelloWorld
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() ->
         {
            var frame = new NotHelloWorldFrame();
            frame.setTitle("NotHelloWorld");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
         });
   }
}

/**
 * A frame that contains a message panel.
 */
class NotHelloWorldFrame extends JFrame
{
   public NotHelloWorldFrame()
   {
      add(new NotHelloWorldComponent());//将给定组件添加到该框架的内容窗格中
      pack();//调整窗口大小，考虑其组件的首选大小
   }
}

/**
 * A component that displays a message.
 */
class NotHelloWorldComponent extends JComponent
{
   public static final int MESSAGE_X = 75;
   public static final int MESSAGE_Y = 100;

   private static final int DEFAULT_WIDTH = 300;
   private static final int DEFAULT_HEIGHT = 200;

   public void paintComponent(Graphics g)//覆盖这个方法描述一个如何绘制自己的组件
   {
      g.drawString("Not a Hello, World program", MESSAGE_X, MESSAGE_Y);
   }

   public Dimension getPreferredSize() //覆盖这个方法，返回这个组件的首选大小
   {  
      return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); 
   }
}