java时钟 java题目求解!求附上代码,并有代码的重要解析题目:利用Java的GUI和多线程编程技术,编写一个时钟显示程序。 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 一个 π 是180° HRadian=(PI/6)*Hour+(PI/360)*Minute+(PI/21600)*Second; PI是π的近似值 PI/6 就是每一个小时占的弧度PI/360 是每一个分钟占的弧度PI/360其实是PI/(6*60) PI/21600是PI/(6*60*60)每一分钟在π里占的弧度 以此类推。import java.util.*;import java.awt.*;import java.applet.*;import java.text.*;public class Exam5Test8 extends Applet implements Runnable { private volatile Thread timer; // The thread that displays clock private int lastxs, lastys, lastxm, lastym, lastxh, lastyh; // Dimensions used to draw hands private SimpleDateFormat formatter; // Formats the date displayed private String lastdate; // String to hold date displayed private Font clockFaceFont; // Font for number display on clock private Date currentDate; // Used to get date to display private Color handColor; // Color of main hands and dial private Color numberColor; // Color of second hand and numbers private int xcenter = 80, ycenter = 55; // Center position public void init() { int x, y; lastxs = lastys = lastxm = lastym = lastxh = lastyh = 0; formatter = new SimpleDateFormat("EEE MMM dd hh:mm:ss yyyy", Locale.getDefault()); currentDate = new Date(); lastdate = formatter.format(currentDate); clockFaceFont = new Font("Serif", Font.PLAIN, 14); handColor = Color.blue; numberColor = Color.darkGray; try { setBackground(new Color(Integer.parseInt(getParameter("bgcolor"),16))); } catch (NullPointerException e) { } catch (NumberFormatException e) { } try { handColor = new Color(Integer.parseInt(getParameter("fgcolor1"), 16)); } catch (NullPointerException e) { } catch (NumberFormatException e) { } try { numberColor = new Color(Integer.parseInt(getParameter("fgcolor2"),16)); } catch (NullPointerException e) { } catch (NumberFormatException e) { } resize(300, 300); // Set clock window size } // Paint is the main part of the program //更新时钟的显示时间 public void update(Graphics g) { int xh, yh, xm, ym, xs, ys; int s = 0, m = 10, h = 10; String today; currentDate = new Date(); formatter.applyPattern("s"); try { s = Integer.parseInt(formatter.format(currentDate)); } catch (NumberFormatException n) { s = 0; } formatter.applyPattern("m"); try { m = Integer.parseInt(formatter.format(currentDate)); } catch (NumberFormatException n) { m = 10; } formatter.applyPattern("h"); try { h = Integer.parseInt(formatter.format(currentDate)); } catch (NumberFormatException n) { h = 10; } // Set position of the ends of the hands xs = (int) (Math.cos(s * Math.PI / 30 - Math.PI / 2) * 45 + xcenter); ys = (int) (Math.sin(s * Math.PI / 30 - Math.PI / 2) * 45 + ycenter); xm = (int) (Math.cos(m * Math.PI / 30 - Math.PI / 2) * 40 + xcenter); ym = (int) (Math.sin(m * Math.PI / 30 - Math.PI / 2) * 40 + ycenter); xh = (int) (Math.cos((h * 30 + m / 2) * Math.PI / 180 - Math.PI / 2) * 30 + xcenter); yh = (int) (Math.sin((h * 30 + m / 2) * Math.PI / 180 - Math.PI / 2) * 30 + ycenter); // Get the date to print at the bottom formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy"); today = formatter.format(currentDate); g.setFont(clockFaceFont); // Erase if necessary g.setColor(getBackground()); if (xs != lastxs || ys != lastys) { g.drawLine(xcenter, ycenter, lastxs, lastys); g.drawString(lastdate, 5, 125); } if (xm != lastxm || ym != lastym) { g.drawLine(xcenter, ycenter - 1, lastxm, lastym); g.drawLine(xcenter - 1, ycenter, lastxm, lastym); } if (xh != lastxh || yh != lastyh) { g.drawLine(xcenter, ycenter - 1, lastxh, lastyh); g.drawLine(xcenter - 1, ycenter, lastxh, lastyh); } // Draw date and hands g.setColor(numberColor); g.drawString(today, 5, 125); g.drawLine(xcenter, ycenter, xs, ys); g.setColor(handColor); g.drawLine(xcenter, ycenter - 1, xm, ym); g.drawLine(xcenter - 1, ycenter, xm, ym); g.drawLine(xcenter, ycenter - 1, xh, yh); g.drawLine(xcenter - 1, ycenter, xh, yh); lastxs = xs; lastys = ys; lastxm = xm; lastym = ym; lastxh = xh; lastyh = yh; lastdate = today; currentDate = null; } //描绘出时钟表 public void paint(Graphics g) { g.setFont(clockFaceFont); // Draw the circle and numbers g.setColor(handColor); g.drawArc(xcenter - 50, ycenter - 50, 100, 100, 0, 360); g.setColor(numberColor); g.drawString("9", xcenter - 45, ycenter + 3); g.drawString("3", xcenter + 40, ycenter + 3); g.drawString("12", xcenter - 5, ycenter - 37); g.drawString("6", xcenter - 3, ycenter + 45); // Draw date and hands g.setColor(numberColor); g.drawString(lastdate, 5, 125); g.drawLine(xcenter, ycenter, lastxs, lastys); g.setColor(handColor); g.drawLine(xcenter, ycenter - 1, lastxm, lastym); g.drawLine(xcenter - 1, ycenter, lastxm, lastym); g.drawLine(xcenter, ycenter - 1, lastxh, lastyh); g.drawLine(xcenter - 1, ycenter, lastxh, lastyh); } public void start() { timer = new Thread(this); timer.start(); } public void stop() { timer = null; } public void run() { Thread me = Thread.currentThread(); while (timer == me) { try { Thread.currentThread().sleep(100); } catch (InterruptedException e) { } repaint(); } } /*返回有关此 applet 的信息。applet 应该重写此方法,返回包含有关 applet 的作者、版本和版权信息的 String。 Applet 类提供的此方法实现返回 null */ public String getAppletInfo() { return "Title: A Clock \n" + "Author: 陈金林, 2011 \n" + "An analog clock."; } /*返回此 applet 理解的关于参数的信息。applet 应该重写此方法,返回描述这些参数的 String 数组。 数组的每个元素应该是三个 String 的集合,包括名称、类型和描述。 */ public String[][] getParameterInfo() { String[][] info = { { "bgcolor", "hexadecimal RGB number", "The background color. Default is the color of your browser." }, { "fgcolor1", "hexadecimal RGB number", "The color of the hands and dial. Default is blue." }, { "fgcolor2", "hexadecimal RGB number", "The color of the second hand and numbers. Default is dark gray." } }; return info; }} package event;import java.awt.event.*;import java.awt.*;import java.util.Calendar;import java.util.GregorianCalendar;import javax.swing.*;public class ClockAnimation extends JFrame{private StillClock clock=new StillClock();public ClockAnimation(){add(clock); Timer timer=new Timer(1000,new TimerListener());timer.start();}private class TimerListener implements ActionListener{public void actionPerformed(ActionEvent e ){clock.setCurrentTime();clock.repaint();}}public static void main(String [] args){ClockAnimation frame=new ClockAnimation();frame.setSize(400,200);frame.setVisible(true);frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setTitle("ClockAnimation");}}class StillClock extends JPanel { private int hour; private int minute; private int second; /** Construct a default clock with the current time*/ public StillClock() { setCurrentTime(); } /** Construct a clock with specified hour, minute, and second */ public StillClock(int hour, int minute, int second) { this.hour = hour; this.minute = minute; this.second = second; } /** Return hour */ public int getHour() { return hour; } /** Set a new hour */ public void setHour(int hour) { this.hour = hour; repaint(); } /** Return minute */ public int getMinute() { return minute; } /** Set a new minute */ public void setMinute(int minute) { this.minute = minute; repaint(); } /** Return second */ public int getSecond() { return second; } /** Set a new second */ public void setSecond(int second) { this.second = second; repaint(); } /** Draw the clock */ protected void paintComponent(Graphics g) { super.paintComponent(g); // Initialize clock parameters int clockRadius = (int)(Math.min(getWidth(), getHeight()) * 0.8 * 0.5); int xCenter = getWidth() / 2; int yCenter = getHeight() / 2; // Draw circle g.setColor(Color.black); g.drawOval(xCenter - clockRadius, yCenter - clockRadius, 2 * clockRadius, 2 * clockRadius); g.drawString("12", xCenter - 5, yCenter - clockRadius + 12); g.drawString("9", xCenter - clockRadius + 3, yCenter + 5); g.drawString("3", xCenter + clockRadius - 10, yCenter + 3); g.drawString("6", xCenter - 3, yCenter + clockRadius - 3); // Draw second hand int sLength = (int)(clockRadius * 0.8); int xSecond = (int)(xCenter + sLength * Math.sin(second * (2 * Math.PI / 60))); int ySecond = (int)(yCenter - sLength * Math.cos(second * (2 * Math.PI / 60))); g.setColor(Color.red); g.drawLine(xCenter, yCenter, xSecond, ySecond); // Draw minute hand int mLength = (int)(clockRadius * 0.65); int xMinute = (int)(xCenter + mLength * Math.sin(minute * (2 * Math.PI / 60))); int yMinute = (int)(yCenter - mLength * Math.cos(minute * (2 * Math.PI / 60))); g.setColor(Color.blue); g.drawLine(xCenter, yCenter, xMinute, yMinute); // Draw hour hand int hLength = (int)(clockRadius * 0.5); int xHour = (int)(xCenter + hLength * Math.sin((hour % 12 + minute / 60.0) * (2 * Math.PI / 12))); int yHour = (int)(yCenter - hLength * Math.cos((hour % 12 + minute / 60.0) * (2 * Math.PI / 12))); g.setColor(Color.green); g.drawLine(xCenter, yCenter, xHour, yHour); } public void setCurrentTime() { // Construct a calendar for the current date and time Calendar calendar = new GregorianCalendar(); // Set current hour, minute and second this.hour = calendar.get(Calendar.HOUR_OF_DAY); this.minute = calendar.get(Calendar.MINUTE); this.second = calendar.get(Calendar.SECOND); } public Dimension getPreferredSize() { return new Dimension(200, 200); } } 字符串问题 setBackground设置背景颜色问题 求一个关于编码转换的问题,在线等 关于右键菜单 JFileChooser 我有一套JSP源程序,想修改一下为我所用,但是有点麻烦 请问在JAVA编程中,内部类用的多不多? ***关于文件流的flush,应该很经典*** 很急!有关jacob的! 多线程问题,20分 如何将现有网站整合Openfire啊?如何实现同步增删好友? 菜鸟求助:关于I/O和排序
import java.util.*;
import java.awt.*;
import java.applet.*;
import java.text.*;
public class Exam5Test8 extends Applet implements Runnable {
private volatile Thread timer; // The thread that displays clock
private int lastxs, lastys, lastxm, lastym, lastxh, lastyh; // Dimensions used to draw hands
private SimpleDateFormat formatter; // Formats the date displayed
private String lastdate; // String to hold date displayed
private Font clockFaceFont; // Font for number display on clock
private Date currentDate; // Used to get date to display
private Color handColor; // Color of main hands and dial
private Color numberColor; // Color of second hand and numbers
private int xcenter = 80, ycenter = 55; // Center position
public void init() {
int x, y;
lastxs = lastys = lastxm = lastym = lastxh = lastyh = 0;
formatter = new SimpleDateFormat("EEE MMM dd hh:mm:ss yyyy", Locale.getDefault());
currentDate = new Date();
lastdate = formatter.format(currentDate);
clockFaceFont = new Font("Serif", Font.PLAIN, 14);
handColor = Color.blue;
numberColor = Color.darkGray;
try {
setBackground(new Color(Integer.parseInt(getParameter("bgcolor"),16)));
} catch (NullPointerException e) {
} catch (NumberFormatException e) {
}
try {
handColor = new Color(Integer.parseInt(getParameter("fgcolor1"), 16));
} catch (NullPointerException e) {
} catch (NumberFormatException e) {
}
try {
numberColor = new Color(Integer.parseInt(getParameter("fgcolor2"),16));
} catch (NullPointerException e) {
} catch (NumberFormatException e) {
}
resize(300, 300); // Set clock window size
}
// Paint is the main part of the program
//更新时钟的显示时间
public void update(Graphics g) {
int xh, yh, xm, ym, xs, ys;
int s = 0, m = 10, h = 10;
String today;
currentDate = new Date();
formatter.applyPattern("s");
try {
s = Integer.parseInt(formatter.format(currentDate));
} catch (NumberFormatException n) {
s = 0;
}
formatter.applyPattern("m");
try {
m = Integer.parseInt(formatter.format(currentDate));
} catch (NumberFormatException n) {
m = 10;
}
formatter.applyPattern("h");
try {
h = Integer.parseInt(formatter.format(currentDate));
} catch (NumberFormatException n) {
h = 10;
}
// Set position of the ends of the hands
xs = (int) (Math.cos(s * Math.PI / 30 - Math.PI / 2) * 45 + xcenter);
ys = (int) (Math.sin(s * Math.PI / 30 - Math.PI / 2) * 45 + ycenter);
xm = (int) (Math.cos(m * Math.PI / 30 - Math.PI / 2) * 40 + xcenter);
ym = (int) (Math.sin(m * Math.PI / 30 - Math.PI / 2) * 40 + ycenter);
xh = (int) (Math.cos((h * 30 + m / 2) * Math.PI / 180 - Math.PI / 2) * 30 + xcenter);
yh = (int) (Math.sin((h * 30 + m / 2) * Math.PI / 180 - Math.PI / 2) * 30 + ycenter);
// Get the date to print at the bottom
formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy");
today = formatter.format(currentDate);
g.setFont(clockFaceFont);
// Erase if necessary
g.setColor(getBackground());
if (xs != lastxs || ys != lastys) {
g.drawLine(xcenter, ycenter, lastxs, lastys);
g.drawString(lastdate, 5, 125);
}
if (xm != lastxm || ym != lastym) {
g.drawLine(xcenter, ycenter - 1, lastxm, lastym);
g.drawLine(xcenter - 1, ycenter, lastxm, lastym);
}
if (xh != lastxh || yh != lastyh) {
g.drawLine(xcenter, ycenter - 1, lastxh, lastyh);
g.drawLine(xcenter - 1, ycenter, lastxh, lastyh);
}
// Draw date and hands
g.setColor(numberColor);
g.drawString(today, 5, 125);
g.drawLine(xcenter, ycenter, xs, ys);
g.setColor(handColor);
g.drawLine(xcenter, ycenter - 1, xm, ym);
g.drawLine(xcenter - 1, ycenter, xm, ym);
g.drawLine(xcenter, ycenter - 1, xh, yh);
g.drawLine(xcenter - 1, ycenter, xh, yh);
lastxs = xs;
lastys = ys;
lastxm = xm;
lastym = ym;
lastxh = xh;
lastyh = yh;
lastdate = today;
currentDate = null;
}
//描绘出时钟表
public void paint(Graphics g) {
g.setFont(clockFaceFont);
// Draw the circle and numbers
g.setColor(handColor);
g.drawArc(xcenter - 50, ycenter - 50, 100, 100, 0, 360);
g.setColor(numberColor);
g.drawString("9", xcenter - 45, ycenter + 3);
g.drawString("3", xcenter + 40, ycenter + 3);
g.drawString("12", xcenter - 5, ycenter - 37);
g.drawString("6", xcenter - 3, ycenter + 45);
// Draw date and hands
g.setColor(numberColor);
g.drawString(lastdate, 5, 125);
g.drawLine(xcenter, ycenter, lastxs, lastys);
g.setColor(handColor);
g.drawLine(xcenter, ycenter - 1, lastxm, lastym);
g.drawLine(xcenter - 1, ycenter, lastxm, lastym);
g.drawLine(xcenter, ycenter - 1, lastxh, lastyh);
g.drawLine(xcenter - 1, ycenter, lastxh, lastyh);
}
public void start() {
timer = new Thread(this);
timer.start();
}
public void stop() {
timer = null;
}
public void run() {
Thread me = Thread.currentThread();
while (timer == me) {
try {
Thread.currentThread().sleep(100);
} catch (InterruptedException e) {
}
repaint();
}
}
/*返回有关此 applet 的信息。applet 应该重写此方法,返回包含有关 applet 的作者、版本和版权信息的 String。
Applet 类提供的此方法实现返回 null
*/
public String getAppletInfo() {
return "Title: A Clock \n" + "Author: 陈金林, 2011 \n"
+ "An analog clock.";
}
/*返回此 applet 理解的关于参数的信息。applet 应该重写此方法,返回描述这些参数的 String 数组。
数组的每个元素应该是三个 String 的集合,包括名称、类型和描述。
*/
public String[][] getParameterInfo() {
String[][] info = {
{ "bgcolor", "hexadecimal RGB number",
"The background color. Default is the color of your browser." },
{ "fgcolor1", "hexadecimal RGB number",
"The color of the hands and dial. Default is blue." },
{ "fgcolor2", "hexadecimal RGB number",
"The color of the second hand and numbers. Default is dark gray." } };
return info;
}
}
import java.awt.event.*;
import java.awt.*;
import java.util.Calendar;
import java.util.GregorianCalendar;import javax.swing.*;
public class ClockAnimation extends JFrame{
private StillClock clock=new StillClock();public ClockAnimation()
{
add(clock);
Timer timer=new Timer(1000,new TimerListener());
timer.start();}
private class TimerListener implements ActionListener
{
public void actionPerformed(ActionEvent e )
{
clock.setCurrentTime();
clock.repaint();}
}
public static void main(String [] args)
{
ClockAnimation frame=new ClockAnimation();
frame.setSize(400,200);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("ClockAnimation");}
}
class StillClock extends JPanel {
private int hour;
private int minute;
private int second; /** Construct a default clock with the current time*/
public StillClock() {
setCurrentTime();
} /** Construct a clock with specified hour, minute, and second */
public StillClock(int hour, int minute, int second) {
this.hour = hour;
this.minute = minute;
this.second = second;
} /** Return hour */
public int getHour() {
return hour;
} /** Set a new hour */
public void setHour(int hour) {
this.hour = hour;
repaint();
} /** Return minute */
public int getMinute() {
return minute;
} /** Set a new minute */
public void setMinute(int minute) {
this.minute = minute;
repaint();
} /** Return second */
public int getSecond() {
return second;
} /** Set a new second */
public void setSecond(int second) {
this.second = second;
repaint();
} /** Draw the clock */
protected void paintComponent(Graphics g) {
super.paintComponent(g); // Initialize clock parameters
int clockRadius =
(int)(Math.min(getWidth(), getHeight()) * 0.8 * 0.5);
int xCenter = getWidth() / 2;
int yCenter = getHeight() / 2; // Draw circle
g.setColor(Color.black);
g.drawOval(xCenter - clockRadius, yCenter - clockRadius,
2 * clockRadius, 2 * clockRadius);
g.drawString("12", xCenter - 5, yCenter - clockRadius + 12);
g.drawString("9", xCenter - clockRadius + 3, yCenter + 5);
g.drawString("3", xCenter + clockRadius - 10, yCenter + 3);
g.drawString("6", xCenter - 3, yCenter + clockRadius - 3); // Draw second hand
int sLength = (int)(clockRadius * 0.8);
int xSecond = (int)(xCenter + sLength *
Math.sin(second * (2 * Math.PI / 60)));
int ySecond = (int)(yCenter - sLength *
Math.cos(second * (2 * Math.PI / 60)));
g.setColor(Color.red);
g.drawLine(xCenter, yCenter, xSecond, ySecond); // Draw minute hand
int mLength = (int)(clockRadius * 0.65);
int xMinute = (int)(xCenter + mLength *
Math.sin(minute * (2 * Math.PI / 60)));
int yMinute = (int)(yCenter - mLength *
Math.cos(minute * (2 * Math.PI / 60)));
g.setColor(Color.blue);
g.drawLine(xCenter, yCenter, xMinute, yMinute); // Draw hour hand
int hLength = (int)(clockRadius * 0.5);
int xHour = (int)(xCenter + hLength *
Math.sin((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)));
int yHour = (int)(yCenter - hLength *
Math.cos((hour % 12 + minute / 60.0) * (2 * Math.PI / 12)));
g.setColor(Color.green);
g.drawLine(xCenter, yCenter, xHour, yHour);
} public void setCurrentTime() {
// Construct a calendar for the current date and time
Calendar calendar = new GregorianCalendar(); // Set current hour, minute and second
this.hour = calendar.get(Calendar.HOUR_OF_DAY);
this.minute = calendar.get(Calendar.MINUTE);
this.second = calendar.get(Calendar.SECOND);
} public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}