實驗十六線程技術

時間 2019-11-10

標籤實驗十六線程技術简体版

原文原文鏈接

實驗十六線程技術java

實驗時間 2017-12-8編程

一基礎知識canvas

程序是一段靜態的代碼，它是應用程序執行的藍本。進程是程序的一次動態執行，它對應了從代碼加載、執行至執行完畢的一個完整過程。操做系統爲每一個進程分配一段獨立的內存空間和系統資源，包括：代碼數據以及堆棧等資源。每個進程的內部數據和狀態都是徹底獨立的。多任務操做系統中，進程切換對CPU資源消耗較大。多線程

多線程是進程執行過程當中產生的多條執行線索。線程是比進程執行更小的單位。線程不能獨立存在，必須存在於進程中，同一進程的各線程間共享進程空間的數據。每一個線程有它自身的產生、存在和消亡的過程，是一個動態的概念。多線程意味着一個程序的多行語句能夠看上去幾乎在同一時間內同時運行。線程建立、銷燬和切換的負荷遠小於進程，又稱爲輕量級進程。dom

Java實現多線程有兩種途徑：建立Thread類的子類；在程序中定義實現Runnable接口的類。ide

用Thread類的子類建立線程：首先需從Thread類派生出一個子類，在該子類中重寫run()方法。而後用建立該子類的對象Lefthand left=new Lefthand(); Righthand right=new Righthand();最後用start()方法啓動線程 left.start(); right.start();佈局

用Thread類的子類建立多線程的關鍵性操做：定義Thread類的子類並實現用戶線程操做，即run()方法的實現。在適當的時候啓動線程。因爲Java只支持單重繼承，用這種方法定義的類不可再繼承其餘父類。測試

用Runnable()接口實現線程：首先設計一個實現Runnable接口的類；而後在類中根據須要重寫run方法；再建立該類對象，以此對象爲參數創建Thread 類的對象；調用Thread類對象的start方法啓動線程，將 CPU執行權轉交到run方法。this

Thread(Runnable r)：建立一個新線程，它調用r的run(), r是一個實現了Runnable接口的類的實例。spa

線程兩種建立方法比較：實現Runnable接口的優點：符合OO設計的思想；便於用extends繼承其它類。採用繼承Thread類方法的優勢：代碼簡單。

線程的終止：當線程的run方法執行方法體中最後一條語句後，或者出現了在run方法中沒有捕獲的異常時，線程將終止，讓出CPU使用權。調用interrupt()方法也可終止線程。 void interrupt() ：向一個線程發送一箇中斷請求，同時把這個線程的「interrupted」狀態置爲true。若該線程處於 blocked 狀態，會拋出 InterruptedException。

測試線程是否被中斷的方法：static boolean interrupted() ：檢測當前線程是否已被中斷，並重置狀態「interrupted」值爲false。 boolean isInterrupted() ：檢測當前線程是否已被中斷，不改變狀態「interrupted」值。

二實驗部分

1、實驗目的與要求

(1) 掌握線程概念；

(2) 掌握線程建立的兩種技術；

(3) 理解和掌握線程的優先級屬性及調度方法；

(4) 掌握線程同步的概念及實現技術；

2、實驗內容和步驟

實驗1：測試程序並進行代碼註釋。

測試程序1：

l 在elipse IDE中調試運行ThreadTest，結合程序運行結果理解程序；

l 掌握線程概念；

l 掌握用Thread的擴展類實現線程的方法；

package aha;

//從Thread類中派生出一個子類Lefthand
class Lefthand extends Thread { 
       public void run()
       {
           for(int i=0;i<=5;i++)
           {  System.out.println("You are Students!");
               try{   sleep(500);   }
               catch(InterruptedException e)//異常捕獲
               { System.out.println("Lefthand error.");}    
           } 
      } 
    }
//從Thread類中派生出一個子類Lefthand
    class Righthand extends Thread {
        public void run()
        {
             for(int i=0;i<=5;i++)
             {   System.out.println("I am a Teacher!");
                 try{  sleep(300);  }
                 catch(InterruptedException e)//異常捕獲
                 { System.out.println("Righthand error.");}
             }
        }
    }
    public class ThreadTest 
    {
        //屬性
         static Lefthand left;
         static Righthand right;
         public static void main(String[] args)
         {     left=new Lefthand();//建立Lefthand類對象
               right=new Righthand();//建立Righthand類對象
               //用start（）方法啓動線程
               left.start();
               right.start();
         }
    }

l 利用Runnable接口改造程序，掌握用Runnable接口建立線程的方法。

package shiyan;

//建立實現Runnable類的接口
class Lefthand implements Runnable { 
       public void run()
       {
           for(int i=0;i<=5;i++)
           {  System.out.println("You are Students!");
               try{   Thread.sleep(500);   }
               catch(InterruptedException e)//異常捕獲
               { System.out.println("Lefthand error.");}    
           } 
      } 
    }
//建立實現Runnable類的接口
    class Righthand implements Runnable{
        public void run()
        {
             for(int i=0;i<=5;i++)
             {   System.out.println("I am a Teacher!");
                 try{  Thread.sleep(300);  }
                 catch(InterruptedException e)//異常捕獲
                 { System.out.println("Righthand error.");}
             }
        }
    }
    public class ThreadTest 
    {    //屬性
         static Thread left;
         static Thread right;
         public static void main(String[] args)
         {    Runnable left=new Lefthand();             
              Thread l=new Thread (left);//轉換爲    Thread類對象          
               l.start();//啓動線程
               Runnable right=new Righthand();
               Thread r=new Thread (right);//轉換爲    Thread類對象          
               r.start();//啓動線程
         }
    }

class Lefthand extends Thread {

public void run()

{

for(int i=0;i<=5;i++)

{ System.out.println("You are Students!");

try{ sleep(500); }

catch(InterruptedException e)

{ System.out.println("Lefthand error.");}

}

class Righthand extends Thread {

public void run()

{

for(int i=0;i<=5;i++)

{ System.out.println("I am a Teacher!");

try{ sleep(300); }

catch(InterruptedException e)

{ System.out.println("Righthand error.");}

}

public class ThreadTest

{

static Lefthand left;

static Righthand right;

public static void main(String[] args)

{ left=new Lefthand();

right=new Righthand();

left.start();

right.start();

}

測試程序2：

l 在Elipse環境下調試教材625頁程序14-一、14-2 、14-3，結合程序運行結果理解程序；

package bounceThread;

import java.awt.geom.*;

/**
   A ball that moves and bounces off the edges of a 
   rectangle
 * @version 1.33 2007-05-17
 * @author Cay Horstmann
*/
public class Ball
{
   private static final int XSIZE = 15;
   private static final int YSIZE = 15;
   private double x = 0;
   private double y = 0;
   private double dx = 1;
   private double dy = 1;

   /**
      Moves the ball to the next position, reversing direction
      if it hits one of the edges
   */
   //定義了移動方法
   public void move(Rectangle2D bounds)
   {
      x += dx;
      y += dy;
      if (x < bounds.getMinX())
      { 
         x = bounds.getMinX();
         dx = -dx;
      }
      if (x + XSIZE >= bounds.getMaxX())
      {
         x = bounds.getMaxX() - XSIZE; 
         dx = -dx; 
      }
      if (y < bounds.getMinY())
      {
         y = bounds.getMinY(); 
         dy = -dy;
      }
      if (y + YSIZE >= bounds.getMaxY())
      {
         y = bounds.getMaxY() - YSIZE;
         dy = -dy; 
      }
   }

   /**
      Gets the shape of the ball at its current position.
   */
   //定義球外形
   public Ellipse2D getShape()
   {
      return new Ellipse2D.Double(x, y, XSIZE, YSIZE);
   }
}

Ball

package bounce;

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

/**
 * The component that draws the balls.
 * @version 1.34 2012-01-26
 * @author Cay Horstmann
 */
public class BallComponent extends JPanel
{
   private static final int DEFAULT_WIDTH = 450;
   private static final int DEFAULT_HEIGHT = 350;

   private java.util.List<Ball> balls = new ArrayList<>();

   /**
    * Add a ball to the component.
    * @param b the ball to add
    */
   public void add(Ball b)
   {
      balls.add(b);
   }

   public void paintComponent(Graphics g)
   {
      super.paintComponent(g); // erase background
      Graphics2D g2 = (Graphics2D) g;
      for (Ball b : balls)
      {
         g2.fill(b.getShape());
      }
   }
   
   public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}

BallComponent

package bounce;

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

/**
 * Shows an animated bouncing ball.
 * @version 1.34 2015-06-21
 * @author Cay Horstmann
 */
public class Bounce
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         JFrame frame = new BounceFrame();
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

/**
 * The frame with ball component and buttons.
 */
class BounceFrame extends JFrame
{
   private BallComponent comp;
   public static final int STEPS = 1000;
   public static final int DELAY = 3;

   /**
    * Constructs the frame with the component for showing the bouncing ball and
    * Start and Close buttons
    */
   public BounceFrame()
   {
      setTitle("Bounce");
      comp = new BallComponent();
      add(comp, BorderLayout.CENTER);
      JPanel buttonPanel = new JPanel();
      addButton(buttonPanel, "Start", event -> addBall());//將按鈕放入buttonPanel
      addButton(buttonPanel, "Close", event -> System.exit(0));
      add(buttonPanel, BorderLayout.SOUTH);//將buttonPanel放入邊界管理器的南端
      pack();
   }

   /**
    * Adds a button to a container.
    * @param c the container
    * @param title the button title
    * @param listener the action listener for the button
    */
   public void addButton(Container c, String title, ActionListener listener)
   {
       //生成按鈕對象
      JButton button = new JButton(title);
      c.add(button);
      button.addActionListener(listener);//註冊監聽器事件
   }

   /**
    * Adds a bouncing ball to the panel and makes it bounce 1,000 times.
    */
   public void addBall()
   {
      try
      {
         Ball ball = new Ball();
         comp.add(ball);

         for (int i = 1; i <= STEPS; i++)
         {
            ball.move(comp.getBounds());
            comp.paint(comp.getGraphics());
            Thread.sleep(DELAY);//在兩個球顯示之間有延遲
         }
      }
      catch (InterruptedException e)//中斷異常
      {
      }
   }
}

Bounce

l 在Elipse環境下調試教材631頁程序14-4，結合程序運行結果理解程序；

package bounce;

import java.awt.geom.*;

/**
 * A ball that moves and bounces off the edges of a rectangle
 * @version 1.33 2007-05-17
 * @author Cay Horstmann
 */
public class Ball
{
   private static final int XSIZE = 15;
   private static final int YSIZE = 15;
   private double x = 0;
   private double y = 0;
   private double dx = 1;
   private double dy = 1;

   /**
    * Moves the ball to the next position, reversing direction if it hits one of the edges
    */
   public void move(Rectangle2D bounds)
   {
      x += dx;
      y += dy;
      if (x < bounds.getMinX())
      {
         x = bounds.getMinX();
         dx = -dx;
      }
      if (x + XSIZE >= bounds.getMaxX())
      {
         x = bounds.getMaxX() - XSIZE;
         dx = -dx;
      }
      if (y < bounds.getMinY())
      {
         y = bounds.getMinY();
         dy = -dy;
      }
      if (y + YSIZE >= bounds.getMaxY())
      {
         y = bounds.getMaxY() - YSIZE;
         dy = -dy;
      }
   }

   /**
    * Gets the shape of the ball at its current position.
    */
   public Ellipse2D getShape()
   {
      return new Ellipse2D.Double(x, y, XSIZE, YSIZE);
   }
}

Ball

package bounce;

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

/**
 * The component that draws the balls.
 * @version 1.34 2012-01-26
 * @author Cay Horstmann
 */
public class BallComponent extends JPanel
{
   private static final int DEFAULT_WIDTH = 450;
   private static final int DEFAULT_HEIGHT = 350;

   private java.util.List<Ball> balls = new ArrayList<>();

   /**
    * Add a ball to the component.
    * @param b the ball to add
    */
   public void add(Ball b)
   {
      balls.add(b);
   }

   public void paintComponent(Graphics g)
   {
      super.paintComponent(g); // erase background
      Graphics2D g2 = (Graphics2D) g;
      for (Ball b : balls)
      {
         g2.fill(b.getShape());
      }
   }
   
   public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}

BallComponent

package bounceThread;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

/**
 * Shows animated bouncing balls.
 * @version 1.34 2015-06-21
 * @author Cay Horstmann
 */
public class BounceThread
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         JFrame frame = new BounceFrame();
         frame.setTitle("BounceThread");//設置標題
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//關閉操做
         frame.setVisible(true);//設置可見
      });
   }
}

/**
 * The frame with panel and buttons.
 */
class BounceFrame extends JFrame
{
   private BallComponent comp;
   public static final int STEPS = 1000;
   public static final int DELAY = 5;


   /**
    * Constructs the frame with the component for showing the bouncing ball and
    * Start and Close buttons
    */
   public BounceFrame()
   {
      comp = new BallComponent();
      add(comp, BorderLayout.CENTER);
      JPanel buttonPanel = new JPanel();
      addButton(buttonPanel, "Start", event -> addBall());
      addButton(buttonPanel, "Close", event -> System.exit(0));
      add(buttonPanel, BorderLayout.SOUTH);
      pack();
   }

   /**
    * Adds a button to a container.
    * @param c the container
    * @param title the button title
    * @param listener the action listener for the button
    */
   public void addButton(Container c, String title, ActionListener listener)
   {
      JButton button = new JButton(title);
      c.add(button);
      button.addActionListener(listener);
   }

   /**
    * Adds a bouncing ball to the canvas and starts a thread to make it bounce
    */
   //經過建立線程的方式造成球的移動軌跡
   public void addBall()
   {
      Ball ball = new Ball();
      comp.add(ball);
      Runnable r = () -> { 
         try
         {  
            for (int i = 1; i <= STEPS; i++)
            {
               ball.move(comp.getBounds());
               comp.repaint();
               Thread.sleep(DELAY);
            }
         }
         catch (InterruptedException e)
         {
         }
      };
      Thread t = new Thread(r);//建立線程
      t.start();
   }
}

BounceThread

l 對比兩個程序，理解線程的概念和用途；

l 掌握線程建立的兩種技術。

測試程序3：

分析如下程序運行結果並理解程序。

class Race extends Thread {

public static void main(String args[]) {

Race[] runner=new Race[4];

for(int i=0;i<4;i++) runner[i]=new Race( );

for(int i=0;i<4;i++) runner[i].start( );

runner[1].setPriority(MIN_PRIORITY);

runner[3].setPriority(MAX_PRIORITY);}

public void run( ) {

for(int i=0; i<1000000; i++);

System.out.println(getName()+"線程的優先級是"+getPriority()+"已計算完畢!");

}

package fds;

class Race extends Thread {

      public static void main(String args[]) {

        Race[] runner=new Race[4];

        for(int i=0;i<4;i++) runner[i]=new Race( );

       for(int i=0;i<4;i++) runner[i].start( );
       //改變1號線程與3號線程的優先級
       runner[1].setPriority(MIN_PRIORITY);
       runner[3].setPriority(MAX_PRIORITY);}

      public void run( ) {

          for(int i=0; i<1000000; i++);//延時的做用

          System.out.println(getName()+"線程的優先級是"+getPriority()+"已計算完畢!");

        }

    }

測試程序4

l 教材642頁程序模擬一個有若干帳戶的銀行，隨機地生成在這些帳戶之間轉移錢款的交易。每個帳戶有一個線程。在每一筆交易中，會從線程所服務的帳戶中隨機轉移必定數目的錢款到另外一個隨機帳戶。

l 在Elipse環境下調試教材642頁程序14-五、14-6，結合程序運行結果理解程序；

package unsynch;

import java.util.*;

/**
 *一個有許多銀行帳戶的銀行。
 * @version 1.30 2004-08-01
 * @author Cay Horstmann
 */
public class Bank
{
   private final double[] accounts;

   /**
    * 建造銀行
    * @param n the number of accounts
    * @param initialBalance the initial balance for each account
    */
   public Bank(int n, double initialBalance)
   {
      accounts = new double[n];
      Arrays.fill(accounts, initialBalance);
   }

   /**
    * 把錢從一個帳戶轉到另外一個帳戶。
    * @param from the account to transfer from
    * @param to the account to transfer to
    * @param amount the amount to transfer
    */
   public void transfer(int from, int to, double amount)
   {
      if (accounts[from] < amount) return;
      System.out.print(Thread.currentThread());
      accounts[from] -= amount;
      System.out.printf(" %10.2f from %d to %d", amount, from, to);
      accounts[to] += amount;
      System.out.printf(" Total Balance: %10.2f%n", getTotalBalance());
   }

   /**
    *獲取全部帳戶餘額的總和。
    * @return the total balance
    */
   public double getTotalBalance()
   {
      double sum = 0;

      for (double a : accounts)
         sum += a;

      return sum;
   }

   /**
    * 獲取銀行帳戶的數目
    * @return the number of accounts
    */
   public int size()
   {
      return accounts.length;
   }
}

Bank

package unsynch;

/**
 * This program shows data corruption when multiple threads access a data structure.
 * @version 1.31 2015-06-21
 * @author Cay Horstmann
 */
public class UnsynchBankTest
{
   public static final int NACCOUNTS = 100;
   public static final double INITIAL_BALANCE = 1000;
   public static final double MAX_AMOUNT = 1000;
   public static final int DELAY = 10;
   
   public static void main(String[] args)
   {
      Bank bank = new Bank(NACCOUNTS, INITIAL_BALANCE);
      for (int i = 0; i < NACCOUNTS; i++)
      {
         int fromAccount = i;
         Runnable r = () -> {
            try
            {
               while (true)
               {
                  int toAccount = (int) (bank.size() * Math.random());
                  double amount = MAX_AMOUNT * Math.random();
                  bank.transfer(fromAccount, toAccount, amount);
                  Thread.sleep((int) (DELAY * Math.random()));
               }
            }
            catch (InterruptedException e)
            {
            }            
         };
         Thread t = new Thread(r);
         t.start();
      }
   }
}

UnsynchBankTest

綜合編程練習

編程練習1

設計一個用戶信息採集程序，要求以下：

（1）用戶信息輸入界面以下圖所示:

（2）用戶點擊提交按鈕時，用戶輸入信息顯示控制檯界面；

（3）用戶點擊重置按鈕後，清空用戶已輸入信息；

（4）點擊窗口關閉，程序退出。

運行結果以下

代碼以下

package o;

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;

public class DemoJFrame extends JFrame {
    private JPanel jPanel1;
    private JPanel jPanel2;
    private JPanel jPanel3;
    private JPanel jPanel4;
    private JTextField fieldname;
    private JComboBox comboBox;
    private JTextField fieldadress;
    private ButtonGroup bg;
    private JRadioButton Male;
    private JRadioButton Female;
    private JCheckBox read;
    private JCheckBox sing;
    private JCheckBox dance;

    public DemoJFrame() {
        // 設置窗口大小
        this.setSize(800, 400);
        // 設置可見性
        this.setVisible(true);
        // 設置標題
        this.setTitle("編程練習一");
        // 設置關閉操做
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        // 設置窗口居中
        WinCenter.center(this);
        // 建立四個面板對象
        jPanel1 = new JPanel();
        setJPanel1(jPanel1);                
        jPanel2 = new JPanel();
        setJPanel2(jPanel2);
        jPanel3 = new JPanel();
        setJPanel3(jPanel3);
        jPanel4 = new JPanel();
        setJPanel4(jPanel4);
        // 設置容器的爲流佈局
        FlowLayout flowLayout = new FlowLayout();
        this.setLayout(flowLayout);
        // 將四個面板添加到容器中
        this.add(jPanel1);
        this.add(jPanel2);
        this.add(jPanel3);
        this.add(jPanel4);

    }

    /*
     * 設置面一
     */
    private void setJPanel1(JPanel jPanel) {
        // TODO 自動生成的方法存根
        jPanel.setPreferredSize(new Dimension(700, 45));
        // 給面板的佈局設置爲網格佈局 一行4列
        jPanel.setLayout(new GridLayout(1, 4));
        
        JLabel name = new JLabel("name:");
        name.setSize(100, 50);
        fieldname = new JTextField("");
        fieldname.setSize(80, 20);
        
        JLabel study = new JLabel("qualification:");
        comboBox = new JComboBox();
        comboBox.addItem("初中");
        comboBox.addItem("高中");
        comboBox.addItem("本科");
        jPanel.add(name);
        jPanel.add(fieldname);
        jPanel.add(study);
        jPanel.add(comboBox);

    }

    /*
     * 設置面板二
     */
    private void setJPanel2(JPanel jPanel) {
        // TODO 自動生成的方法存根
        jPanel.setPreferredSize(new Dimension(700, 50));
        // 給面板的佈局設置爲網格佈局 一行4列
        jPanel.setLayout(new GridLayout(1, 4));
        
        JLabel name = new JLabel("address:");
        fieldadress = new JTextField();
        fieldadress.setPreferredSize(new Dimension(150, 50));
        
        JLabel study = new JLabel("hobby:");
        JPanel selectBox = new JPanel();
        selectBox.setBorder(BorderFactory.createTitledBorder(""));
        selectBox.setLayout(new GridLayout(3, 1));
        read = new JCheckBox("reading");
        sing = new JCheckBox("singing");
        dance = new JCheckBox("danceing");
        selectBox.add(read);
        selectBox.add(sing);
        selectBox.add(dance);
        jPanel.add(name);
        jPanel.add(fieldadress);
        jPanel.add(study);
        jPanel.add(selectBox);
    }

    /*
     * 設置面板三
     */
    private void setJPanel3(JPanel jPanel) {
        // TODO 自動生成的方法存根
        jPanel.setPreferredSize(new Dimension(700, 150));
        FlowLayout flowLayout = new FlowLayout(FlowLayout.LEFT);
        jPanel.setLayout(flowLayout);
        JLabel sex = new JLabel("性別:");
        JPanel selectBox = new JPanel();
        selectBox.setBorder(BorderFactory.createTitledBorder(""));
        selectBox.setLayout(new GridLayout(2, 1));
        bg = new ButtonGroup();
        Male = new JRadioButton("male");
        Female = new JRadioButton("female");
        bg.add(Male );
        bg.add(Female);
        selectBox.add(Male);
        selectBox.add(Female);
        jPanel.add(sex);
        jPanel.add(selectBox);

    }

    /*
     * 設置面板四
     */
    private void setJPanel4(JPanel jPanel) {
        // TODO 自動生成的方法存根
        jPanel.setPreferredSize(new Dimension(700, 150));
        FlowLayout flowLayout = new FlowLayout(FlowLayout.CENTER, 50, 10);
        jPanel.setLayout(flowLayout);
        jPanel.setLayout(flowLayout);
        JButton sublite = new JButton("提交");
        JButton reset = new JButton("重置");
        sublite.addActionListener((e) -> valiData());
        reset.addActionListener((e) -> Reset());
        jPanel.add(sublite);
        jPanel.add(reset);
    }

    /*
     * 提交數據
     */
    private void valiData() {
        // TODO 自動生成的方法存根
        // 拿到數據
        String name = fieldname.getText().toString().trim();
        String xueli = comboBox.getSelectedItem().toString().trim();
        String address = fieldadress.getText().toString().trim();
        System.out.println(name);
        System.out.println(xueli);
        String hobbystring="";
        if (read.isSelected()) {
            hobbystring+="reading   ";
        }
        if (sing.isSelected()) {
            hobbystring+="singing   ";
        }
        if (dance.isSelected()) {
            hobbystring+="dancing  ";
        }
        System.out.println(address);
        if (Male.isSelected()) {
            System.out.println("male");
        }
        if (Female.isSelected()) {
            System.out.println("female");
        }
        System.out.println(hobbystring);
    }

    /*
     * 重置
     */
    private void Reset() {
        // TODO 自動生成的方法存根
        fieldadress.setText(null);
        fieldname.setText(null);
        comboBox.setSelectedIndex(0);
        read.setSelected(false);
        sing.setSelected(false);
        dance.setSelected(false);
        bg.clearSelection();
    }
}

DemoJFrame

package o;



import java.awt.EventQueue;

import javax.swing.JFrame;

public class Main {
    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            DemoJFrame page = new DemoJFrame();
        });
    }
}

Main

package o;

import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.Window;

public class WinCenter {
    public static void center(Window win){
        Toolkit tkit = Toolkit.getDefaultToolkit();
        Dimension sSize = tkit.getScreenSize();
        Dimension wSize = win.getSize();
        if(wSize.height > sSize.height){
            wSize.height = sSize.height;
        }
        if(wSize.width > sSize.width){
            wSize.width = sSize.width;
        }
        win.setLocation((sSize.width - wSize.width)/ 2, (sSize.height - wSize.height)/ 2);
    }
}

WinCenter

編程練習2

2．建立兩個線程，每一個線程按順序輸出5次「你好」，每一個「你好」要標明來自哪一個線程及其順序號。

package aha;


class xiancheng1 extends Thread { 
       public void run()
       {
           for(int i=1;i<=5;i++)
           {  System.out.println( i+ "你好~"+"(線程1)");
           try{   sleep(500);   }
           catch(InterruptedException e)//異常捕獲
           { System.out.println("Lefthand error.");}    
           } 
      } 
    }

    class xiancheng2 extends Thread {
        public void run()
        {
             for(int i=1;i<=5;i++)
             {   System.out.println( i+ "你好~"+"(線程2)");
             try{   sleep(500);   }
             catch(InterruptedException e)//異常捕獲
             { System.out.println("Lefthand error.");}    
             }
         }
        
    }
    public class xiancheng 
    {
        //屬性
         static xiancheng1 xian1;
         static xiancheng2 xian2;
         public static void main(String[] args)
         {    xian1=new xiancheng1();
              xian2=new xiancheng2();
              //用start（）方法啓動線程
              xian1.start();
               xian2.start();
         }
    }