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java代码重置的代码 java代码重置的代码是什么

Java中的static方法能否重置和重载

可以被重载,不可以被重写。纠正下,不是重置,是重写。

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解释:

一:static方法是不能被重写的,重写通常针对的是接口方法,而接口方法中只是进行的接口定义,而没有方法的实现,而static方法肯定是要求有方法体的,所以有冲突。

二:static方法是可以重载的,因为重载只是定义了方法名相同,其余的一切参数类型、个数、返回值发生变化都是被允许的,所以是可以重载方法的(实际上就相当于重新创建了一个静态方法)。

JAVA计时器的JAVA代码

import java.util.*;

import java.awt.*;

import java.awt.event.*;

import java.applet.*;

public class Clock extends Applet {

private final Panel pnlTop = new Panel();

private final Panel pnlBot = new Panel();

private final Label lblDate = new Label();

private final Label lblTime = new Label();

private final Label lblWatch = new Label();

private final Button btnGo = new Button("开始");

private final Button btnReset = new Button("重置");

private final Label lblSplit = new Label();

private final Button btnSplit = new Button("定点");

private final Button btnSplitReset = new Button("定点重置");

private final Button btnLapAdd = new Button("冲线");

private final Button btnLapReset = new Button("冲线重置");

private final java.awt.List lstLaps = new java.awt.List();

private final UpdateClockThread ucThread = new UpdateClockThread();

private final StopwatchThread swThread = new StopwatchThread();

private class btnGoListener implements ActionListener {

public void actionPerformed(ActionEvent e) {

if ((btnGo.getLabel().equals("开始")) ||

(btnGo.getLabel().equals("继续"))) {

// Start the clock!

swThread.go();

btnGo.setLabel("停止");

btnGo.setBackground(Color.red);

} else if (btnGo.getLabel().equals("停止")) {

// Stop the clock!

swThread.noGo();

btnGo.setLabel("继续");

btnGo.setBackground(Color.green);

}

}

}

private class btnResetListener implements ActionListener {

/** Actually run when the button gets clicked.

*@param e The event

*/

public void actionPerformed(ActionEvent e) {

swThread.reset();

btnGo.setLabel("开始");

btnGo.setBackground(Color.green);

}

}

/** Listens to the Split button.

* @version CS2136 - Term D'00 - Assignment 5

* @author Peter Cooper Jr.

*/

private class btnSplitListener implements ActionListener {

/** Actually run when the button gets clicked.

*@param e The event

*/

public void actionPerformed(ActionEvent e) {

lblSplit.setText(lblWatch.getText());

}

}

/** Listens to the Split Reset button.

* @version CS2136 - Term D'00 - Assignment 5

* @author Peter Cooper Jr.

*/

private class btnSplitResetListener implements ActionListener {

/** Actually run when the button gets clicked.

*@param e The event

*/

public void actionPerformed(ActionEvent e) {

lblSplit.setText("");

}

}

/** Listens to the Lap Add button.

* @version CS2136 - Term D'00 - Assignment 5

* @author Peter Cooper Jr.

*/

private class btnLapAddListener implements ActionListener {

/** Actually run when the button gets clicked.

*@param e The event

*/

public void actionPerformed(ActionEvent e) {

swThread.addLap();

}

}

/** Listens to the Lap Reset button.

* @version CS2136 - Term D'00 - Assignment 5

* @author Peter Cooper Jr.

*/

private class btnLapResetListener implements ActionListener {

/** Actually run when the button gets clicked.

*@param e The event

*/

public void actionPerformed(ActionEvent e) {

swThread.resetLap();

}

}

/** A thread that updates the current date time.

* @version CS2136 - Term D'00 - Assignment 5

* @author Peter Cooper Jr.

*/

private class UpdateClockThread extends Thread {

/** The actual work of the thread.

*/

public void run() {

while (true) {

Calendar now = Calendar.getInstance();

String month = Integer.toString(now.get(Calendar.MONTH)+1);

String date = Integer.toString(now.get(Calendar.DAY_OF_MONTH));

String year = Integer.toString(now.get(Calendar.YEAR));

String hour = Integer.toString(now.get(Calendar.HOUR));

if (hour.equals("0")) hour = "12";

String minute = Integer.toString(now.get(Calendar.MINUTE));

if (minute.length() == 1) minute = "0" + minute;

String second = Integer.toString(now.get(Calendar.SECOND));

if (second.length() == 1) second = "0" + second;

String ampm = now.get(Calendar.AM_PM) == Calendar.AM

? "AM" : "PM";

lblDate.setText(month + "/" + date + "/" + year);

lblTime.setText(hour + ":" + minute + ":" + second

+ " " + ampm);

try {

sleep(500);

} catch (InterruptedException e) {}

}

}

}

private class StopwatchThread extends Thread {

/** Whether or not stopwatch is running. */

private boolean going = false;

/** Stores elapsed milliseconds of previous runs. */

private long prevElapsed = 0;

/** Stores beginning time of this run. */

private Date startDate = new Date();

/** Current lap number. */

private int lapNum = 0;

/** Elapsed time at end of last lap. */

private long lastLapTime = 0;

/** Returns elapsed time in milliseconds.

*@return The elapsed time

*/

private long elapsedTime() {

return prevElapsed +

(going ? new Date().getTime() - startDate.getTime() : 0);

}

/** Changes the number of elapsed milliseconds into a string.

*@param time Number of elapsed milliseconds

*@return The elapsed time as a string.

*/

private String msToString(long time) {

String ms, sec, min;

if (time % 10 = 5) //round to nearest hundredth

time += 5;

ms = Long.toString(time % 1000);

while (ms.length() 3)

ms = "0" + ms;

ms = ms.substring(0, ms.length() - 1);

time /= 1000;

sec = Long.toString(time % 60);

if (sec.length() == 1) sec = "0" + sec;

time /= 60;

min = Long.toString(time);

return min + ":" + sec + "." + ms;

}

public void go() {

startDate = new Date();

going = true;

}

public void noGo() {

prevElapsed = elapsedTime();

going = false;

}

public void reset() {

going = false;

prevElapsed = 0;

lastLapTime = 0;

}

public void addLap() {

long elapsed = elapsedTime();

lstLaps.add("冲线 " + Integer.toString(++lapNum)+ " -- " +

"用时: " + msToString(elapsed) + " -- " +

"冲线时间: " + msToString(elapsed - lastLapTime));

lastLapTime = elapsed;

}

/** Resets the lap list.

*/

public void resetLap() {

lstLaps.removeAll();

lapNum = 0;

lastLapTime = 0;

}

/** Main code of the thread.

*/

public void run() {

while (true) {

lblWatch.setText(msToString(elapsedTime()));

yield();

}

}

}

public void init() {

setLayout(new GridLayout(2,1));

setBackground(Color.lightGray);

setForeground(Color.black);

pnlTop.setLayout(new GridLayout(4,4));

pnlTop.add(new Label("日期:"));

pnlTop.add(lblDate);

pnlTop.add(new Label("时间:"));

pnlTop.add(lblTime);

pnlTop.add(new Label("计时:"));

//lblWatch.setBackground(Color.black);

lblWatch.setForeground(Color.blue);

pnlTop.add(lblWatch);

pnlTop.add(btnGo);

btnGo.setBackground(Color.green);

pnlTop.add(btnReset);

pnlTop.add(new Label("定点:"));

pnlTop.add(lblSplit);

pnlTop.add(btnSplit);

pnlTop.add(btnSplitReset);

pnlTop.add(new Label("冲线时间:"));

pnlTop.add(new Label());

pnlTop.add(btnLapAdd);

pnlTop.add(btnLapReset);

pnlBot.setLayout(new GridLayout(1,1));

pnlBot.add(lstLaps);

add(pnlTop);

add(pnlBot);

btnGo.addActionListener(new btnGoListener());

btnReset.addActionListener(new btnResetListener());

btnSplit.addActionListener(new btnSplitListener());

btnSplitReset.addActionListener(new btnSplitResetListener());

btnLapAdd.addActionListener(new btnLapAddListener());

btnLapReset.addActionListener(new btnLapResetListener());

swThread.setDaemon(true);

ucThread.setDaemon(true);

swThread.start();

ucThread.start();

}

public static void main(String[] args) {

Clock applet = new Clock();

Frame aFrame = new Frame("计时器");

aFrame.addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0);

}

});

aFrame.add(applet, BorderLayout.CENTER);

aFrame.setSize(400, 200);

applet.init();

applet.start();

aFrame.setVisible(true);

}

}

Java初学 帮帮忙看下代码哪里错了导致程序无法运行

bt2没有初始化,导致出现了空指针异常,

解决办法

bt1 = new Button("重置");

修改成为

bt2 = new Button("重置");

修改后的效果图

当然这段代码还有一些可以完善的地方 ,修改后如下

import java.awt.Button;

import java.awt.Frame;

import java.awt.GridLayout;

import java.awt.Label;

import java.awt.TextField;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

import java.awt.Panel;

public class LoginFrame extends Frame {

Label lb1, lb2;

TextField tf1, tf2;

Button bt1, bt2;

public LoginFrame() {

super("用户登录窗口");

setLayout(new GridLayout(3, 1));

Panel p1 = new Panel();

lb1 = new Label("用户名");

tf1 = new TextField(20);

p1.add(lb1);

p1.add(tf1);

Panel p2 = new Panel();

lb2 = new Label("密 码");// 密码中间补充1个全角的空格 方便和上面的 用户名三个字对齐

tf2 = new TextField(20);

p2.add(lb2);

p2.add(tf2);

Panel p3 = new Panel();

bt1 = new Button("提交");

bt2 = new Button("重置"); //bt1修改成bt2

//bt1 = new Button("重置");

p3.add(bt1);

p3.add(bt2);

add(p1);

add(p2);

add(p3);

pack();

setLocationRelativeTo(null);//窗口居于屏幕中央

setVisible(true);

//点击窗口右上角的关闭按钮时候 , 结束程序

addWindowListener(new WindowAdapter() {

@Override

public void windowClosing(WindowEvent e) {

System.exit(0);//结束程序

}

});

}

public static void main(String[] args) {

LoginFrame lf = new LoginFrame();

}

}

JQuery中如何重置(reset)表单

由于JQuery中,提交表单是像下面这样的:Java代码 $('#myform').submit() $('#myform').submit() 所以,想当然的认为,重置表单,当然就是像下面这样子喽:Java代码 $('#myform').reset() $('#myform').reset()但是,不幸的是,这样写的话,会有一个让你很郁闷的结果,那就是,表单无法重置!后来,上网查了一下,说是,JQuery中没有reset方法,经核对,果然是没有。那有么没有办法通过JQuery来重置表单呢,答案是有的,不过是一种间接的方法,如下:Java代码 $('#myform')[0].reset()也就是通过调用 DOM 中的reset方法来重置表单。

这段java代码是怎么实现的 ?

temp=1 是内循环每次重置起始值为1.

流程实现:比如你要算 1 - 5 的阶乘之和,你就输入了5,num就被设成了5

外循环从1 循环到5,

内循环 通过temp 这个临时值分别算 1 到 5 的阶乘,

即,第一次从1 乘到 1, 得到 1,然后记在sum里面, sum 变成 1

第二次从1 乘到2,得到2 ,继续加在sum里面, sum 变成 3

第三次从1 乘到3,得到6 ,继续加在sum里面, sum 变成 9

以此类推

如果temp不重置的话,最后会算出 1 + 1*1*2 + 2*1*2*3 + 12*1*2*3*4 ......

第二次从1 乘到2,得到2 ,继续加在sum里面

Java 重载 重置

函数重载:

是一个类中声明了多个同名的方法,但有不同的参数个数和参数类型。

函数重置:

是指在子类中声明与父类同名的方法,从而覆盖了父类的方法。重置解决了子类与父类的差异问题。

例子如下:

//重载

class A {

public d (){};

public d (q){};

public d (q,w){};

}

//重置

class B extends A{

public d (q,f){};

}


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