Java开发网 - 请大家帮我改一下这个程序好吗？

Topic: 请大家帮我改一下这个程序好吗？

1.请大家帮我改一下这个程序好吗？

Posted by: dumxz
Posted on: 2006-02-17 13:26

这个程序不知为何，一直都无法编译运行，请大家帮我看看，应该如何更改。
public class Li904 implements Runnable {
Account acc;
public Li904() {
}
public void run() {
acc.deposit(200.0f);
acc.withdraw(100.0f);
}

private static int NUM_OF_THREAD = 10;
static Thread[] threads = new Thread[NUM_OF_THREAD];

public static void main(String[] args){
final Account acc = new Account("王红", 1000.0f);
for (int i = 0; i< NUM_OF_THREAD; i++) {
threads[i] = new Thread(new Li904());
threads[i].start();
}
for (int i=0; i<NUM_OF_THREAD; i++){
try {
threads[i].join(); //等待所有线程运行结束
} catch (InterruptedException e) { }
}
System.out.println("完成，王红的帐户余额为:" + acc.getBalance());
}
}

class Account {
String name;
float amount;

public Account(String name, float amount) {
this.name = name;
this.amount = amount;
}

public void deposit(float amt) {
float tmp = amount;
tmp += amt;

try {
Thread.sleep(1);//模拟其它处理所需要的时间，比如刷新数据库等
} catch (InterruptedException e) { }

amount = tmp;
}

public void withdraw(float amt) {
float tmp = amount;
tmp -= amt;

try {
Thread.sleep(1);//模拟其它处理所需要的时间，比如刷新数据库等
} catch (InterruptedException e) { }

amount = tmp;
}

public float getBalance() {
return amount;
}
}

2.Re:请大家帮我改一下这个程序好吗？ [Re: dumxz]	Copy to clipboard
Posted by: joelwx Posted on: 2006-02-17 16:04 我COPY下来,编译可以过的. 执行有问题... 帮你把错误贴上来!! （缩略图，点击图片链接看原图）

3.Re:请大家帮我改一下这个程序好吗？ [Re: dumxz]

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Posted by: joelwx
Posted on: 2006-02-17 16:11

你那个Li904里的Account acc好像没有new哦~~
修改部份:
public Li904(Account acc) {
this.acc=acc;
}
==============
public static void main(String[] args){
final Account acc = new Account("王红", 1000.0f);
for (int i = 0; i< NUM_OF_THREAD; i++) {
threads[i] = new Thread(new Li904(acc));
threads[i].start();
}
==============
以下是执行结果:
完成，王红的帐户余额为:1100.0
试试看~~

4.Re:请大家帮我改一下这个程序好吗？ [Re: joelwx]

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Posted by: dumxz
Posted on: 2006-02-17 23:19

我根据您说的修改过了，怎么还是出现错误呀。
public class Li904 implements Runnable {
public Li904(Account acc) {
this.acc = acc;
}
public void run() {
acc.deposit(20.0f);
acc.withdraw(10.0f);
}

private static int NUM_OF_THREAD = 100;
static Thread[] threads = new Thread[NUM_OF_THREAD];

public static void main(String[] args){
final Account acc = new Account("王红", 1000.0f);
for (int i = 0; i< NUM_OF_THREAD; i++) {
Li904 my = new Li904(acc);
threads[i] = new Thread(my);
threads[i].start();
}
for (int i=0; i<NUM_OF_THREAD; i++){
try {
threads[i].join(); //等待所有线程运行结束
} catch (InterruptedException e) { }
}
System.out.println("完成，王红的帐户余额为:" + acc.getBalance());
}
}

class Account {
String name;
float amount;

public Account(String name, float amount) {
this.name = name;
this.amount = amount;
}

public void deposit(float amt) {
float tmp = amount;
tmp += amt;

try {
Thread.sleep(1);//模拟其它处理所需要的时间，比如刷新数据库等
} catch (InterruptedException e) { }

amount = tmp;
}

public void withdraw(float amt) {
float tmp = amount;
tmp -= amt;

try {
Thread.sleep(1);//模拟其它处理所需要的时间，比如刷新数据库等
} catch (InterruptedException e) { }

amount = tmp;
}

public float getBalance() {
return amount;
}
}

5.Re:请大家帮我改一下这个程序好吗？ [Re: dumxz]	Copy to clipboard
Posted by: dumxz Posted on: 2006-02-17 23:26 多谢，已经修改好了。

6.请高手指教 [Re: dumxz]

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Posted by: xingchao
Posted on: 2006-02-25 19:48

//AbstractClass.java
import java.awt.*;
import java.applet.*;
abstract class Shapes //抽象类
{
public int x,y;
public int width,height;
public Shapes(int x,int y,int width,int height) //构造方法
{
this.x=x;
this.y=y;
this.width=width;
this.height=height;
}
abstract double getArea(); //抽象方法说明
abstract double getPerimeter(); //抽象方法说明
}
class Square extends Shapes //定义Square类，它是从Shapes抽象类扩展的
{
public double getArea() //抽象方法的实现
{
return(width*height); //计算矩形面积
}
public double getPerimeter() //抽象方法的实现
{
return(2*width+2*height);
}
public Square(int x,int y,int width, int height)
{
super(x,y,width,height); //调用超类的方法
}
}
class Circle extends Shapes //定义Circle类，它是从Shapes抽象类扩展的
{
public double r;
public double getArea() //抽象方法的实现
{
return(r*r*Math.PI); //计算圆面积
}
public double getPerimeter() //抽象方法的实现
{
return(2*Math.PI*r); //计算圆的周长
}
public Circle(int x,int y,int width,int height) //构造方法
{
super(x,y,width,height); //调用超类的方法
r=(float)width/2.0;
}
}
public class AbstractClass extends Applet
{
Square Box = new Square(5,15,20,20); //创建Square类对象，并赋初值
Circle Oval = new Circle(5,50,20,20); //创建Circle类对象，并赋初值
public void paint(Graphics g)
{
g.drawRect(Box.x, Box.y, Box.width,Box.height); //画矩形
g.drawString("Area:"+Box.getArea(),50,35); //按指定位置显示矩形面积
g.drawOval(Oval.x, Oval.y, Oval.width, Oval.height); //画圆形
g.drawString("Area:"+(float)Oval.getArea(),50,70); //按指定位置显示圆面积
}
}
这个程序编译时通过了。但是，在运行时却出现了这样的状况 Exception in thread “main ” java.lang. NoSuchMethodError:main 请问这是怎么回事？？