//计算Plane的时间:"java ComputeTime Plane 20 30 40"
//计算Car007的时间:"java ComputeTime Car007 23 34 45"
//如果第3种交通工具为Ship,则只需要编写Ship.java,运行时输入:"java ComputeTime Ship 22 33 44"
import pkg1.pkg2.*;
import java.lang.*;
public class ComputerTime{
public static void main(String args[]){
System.out.println("交通工具:"+args[0]);
System.out.pirntln("參數A:"+args[1]);
System.out.println("參數B:"+args[2]);
System.out.println("參數C:"+args[3]);
double A=Double.parseDouble(args[1]);
double B=Double.parseDouble(args[2]);
double C=Double.parseDouble(args[3]);
double v,t;
try{ Common d=(Common) Class.forName("pkg1."+args[0]).newInstatnce();
v=d.runtime(A,B,C);
t=1000/v;
System.out.println("平均速度:"+v+"km/h");
System.out.pirntln("運行時間:"+t+"小時");
}
catch(Exception e){
System.out.println("class not found");
}
}
}
package pkg1;
import pkg1.pkg2.*;
public class Car007 implements Common{
public double runtimer(double A,double B,double c)
{
System.out.println("runtime="+(A*B/C));
return A*B/C;
}
}package pkg1;
package pkg1.pkg2.*;
public class Plane implements Common{
public double runtimer(double A,double B,double C){
return A+B+C;
}
}
package pkg1.pkg2;
public interface Common{
double runtimer(double A,double B,double c);
}
疑問:編譯出好多錯誤
package pkg1怎麼找不到?。
try{ Common d=(Common) Class.forName("pkg1."+args[0]).newInstatnce();
v=d.runtime(A,B,C);
t=1000/v;
這一句中的Common是什麼意思?
Common d=(Common) Class.forName("pkg1."+args[0]).newInstatnce();是什麼意思???
這個小程序怎麼改才可以是正確運行的?多謝指點!!
//计算Car007的时间:"java ComputeTime Car007 23 34 45"
//如果第3种交通工具为Ship,则只需要编写Ship.java,运行时输入:"java ComputeTime Ship 22 33 44"
import pkg1.pkg2.*;
import java.lang.*;
public class ComputerTime{
public static void main(String args[]){
System.out.println("交通工具:"+args[0]);
System.out.pirntln("參數A:"+args[1]);
System.out.println("參數B:"+args[2]);
System.out.println("參數C:"+args[3]);
double A=Double.parseDouble(args[1]);
double B=Double.parseDouble(args[2]);
double C=Double.parseDouble(args[3]);
double v,t;
try{ Common d=(Common) Class.forName("pkg1."+args[0]).newInstatnce();
v=d.runtime(A,B,C);
t=1000/v;
System.out.println("平均速度:"+v+"km/h");
System.out.pirntln("運行時間:"+t+"小時");
}
catch(Exception e){
System.out.println("class not found");
}
}
}
package pkg1;
import pkg1.pkg2.*;
public class Car007 implements Common{
public double runtimer(double A,double B,double c)
{
System.out.println("runtime="+(A*B/C));
return A*B/C;
}
}package pkg1;
package pkg1.pkg2.*;
public class Plane implements Common{
public double runtimer(double A,double B,double C){
return A+B+C;
}
}
package pkg1.pkg2;
public interface Common{
double runtimer(double A,double B,double c);
}
疑問:編譯出好多錯誤
package pkg1怎麼找不到?。
try{ Common d=(Common) Class.forName("pkg1."+args[0]).newInstatnce();
v=d.runtime(A,B,C);
t=1000/v;
這一句中的Common是什麼意思?
Common d=(Common) Class.forName("pkg1."+args[0]).newInstatnce();是什麼意思???
這個小程序怎麼改才可以是正確運行的?多謝指點!!
生成了一个Common对象。
如果arg0=“Car”;
则应该在pkg1里面有一个Car类。
Common是Car的超类
----------------------------
http://www.soft51down.cn
//计算Plane的时间:"java ComputeTime Plane 20 30 40"
//计算Car007的时间:"java ComputeTime Car007 23 34 45"
//如果第3种交通工具为Ship,则只需要编写Ship.java,运行时输入:"java ComputeTime Ship 22 33 44"
//import pkg1.*;
//import pkg1.pkg2.*;
import java.lang.*;
public class ComputeTime
{
public static void main(String[] args)
{
System.out.println("交通工具:"+args[0]);
System.out.println("參數A:"+args[1]);
System.out.println("參數B:"+args[2]);
System.out.println("參數C:"+args[3]);
double A=Double.parseDouble(args[1]);
double B=Double.parseDouble(args[2]);
double C=Double.parseDouble(args[3]);
double v,t;
try
{
pkg1.pkg2.Common d=(pkg1.pkg2.Common) Class.forName("pkg1."+args[0]).newInstance();
v=d.runtime(A,B,C);
t=1000/v;
System.out.println("平均速度:"+v+"km/h");
System.out.println("運行時間:"+t+"小時");
}
catch(Exception e)
{
System.out.println("class not found");
}
}
}package pkg1.pkg2;
public interface Common
{
double runtime(double A,double B,double c);
} package pkg1;
import pkg1.pkg2.*;
public class Plane implements Common
{
public double runtime(double A,double B,double C)
{
return (A+B+C)/3;
}
}
package pkg1;
import pkg1.pkg2.*;
public class Car007 implements Common
{
public double runtime(double A,double B,double C)
{
System.out.println("runtime="+(A*B/C));
return A*B/C;
}
}
pkg1.pkg2.Common d=(pkg1.pkg2.Common) Class.forName("pkg1."+args[0]).newInstance();明明import pkg1.pkg2.*;
{
public double runtime(double A,double B,double C)
{
return A+B+C;
}
}
-------------------------------------------------------------------
package pkg1;import pkg1.pkg2.Common;public class Car007 implements Common
{
public double runtime(double A, double B, double C)
{
System.out.println("runtime=" + (A * B / C));
return A * B / C;
}
}
---------------------------------------------------------------------
package pkg1.pkg2; public interface Common
{
double runtime(double A,double B,double C);
}
-----------------------------------------------------------------------
package pkg1.pkg2;public class ComputerTime
{
public static void main(String args[])
{
System.out.println("交通工具:" + args[0]);
System.out.println("參數A:" + args[1]);
System.out.println("參數B:" + args[2]);
System.out.println("參數C:" + args[3]);
double A = Double.parseDouble(args[1]);
double B = Double.parseDouble(args[2]);
double C = Double.parseDouble(args[3]);
double v, t;
try
{
Common d = (Common) Class.forName("pkg1." + args[0]).newInstance();
v = d.runtime(A, B, C);
t = 1000 / v;
System.out.println("平均速度:" + v + "km/h");
System.out.println("運行時間:" + t + "小時");
}
catch (Exception e)
{
System.out.println("class not found");
}
}
}
------------------------------------------------------------------------------------------------Class.forName("pkg1."+args[0]).newInstance(); "pkg1."+args[0] = pkg1.类 得到这个包的类的一个新实例,如Plane,Car007