Java中setters和getters的意义是什么？
2022-09-01 10:11:17
请原谅长度，但这里有两个程序，它们都完全相同，但一个带有和一个没有 setter、getter 和构造函数。
我以前上过一堂基本的C++课，不记得其中的任何一个，目前我还没有看到它们的意义，如果有人可以用拉门的术语解释它们，我将不胜感激......目前，它们似乎只不过是浪费空间，以使我的代码看起来更长，但老师说它们很重要（到目前为止就是这样）。
提前致谢！现在代码如下：里程.java：
package gasMileage;
import java.util.Scanner; //program uses class Scanner
public class Mileage
{
public int restart;
public double miles, gallons, totalMiles, totalGallons, milesPerGallon;
public Mileage(int newRestart, double newMiles, double newGallons,
double newTotalMiles, double newTotalGallons, double newMilesPerGallon)
{
setRestart(newRestart);
setMiles(newMiles);
setGallons(newGallons);
setTotalMiles(newTotalMiles);
setTotalGallons(newTotalGallons);
setMilesPerGallon(newMilesPerGallon);
}
public void setRestart(int newRestart)
{
restart = newRestart;
}
public int getRestart()
{
return restart;
}
public void setMiles(double newMiles)
{
miles = newMiles;
}
public double getMiles()
{
return miles;
}
public void setGallons(double newGallons)
{
gallons = newGallons;
}
public double getGallons()
{
return gallons;
}
public void setTotalMiles(double newTotalMiles)
{
totalMiles = newTotalMiles;
}
public double getTotalMiles()
{
return totalMiles;
}
public void setTotalGallons(double newTotalGallons)
{
totalGallons = newTotalGallons;
}
public double getTotalGallons()
{
return totalGallons;
}
public void setMilesPerGallon(double newMilesPerGallon)
{
milesPerGallon = newMilesPerGallon;
}
public double getMilesPerGallon()
{
return milesPerGallon;
}
public void calculateMileage()
{
Scanner input = new Scanner(System.in);
while(restart == 1)
{
System.out.print("Please input number of miles you drove: ");
miles = input.nextDouble();
totalMiles = totalMiles + miles;
System.out.print("Please input number of gallons you used: ");
gallons = input.nextDouble();
totalGallons = totalGallons + gallons;
milesPerGallon = miles / gallons;
System.out.printf("Your mileage is %.2f MPG.\n", milesPerGallon);
System.out.print("Would you like to try again? 1 for yes, 2 for no: ");
restart = input.nextInt();
}
milesPerGallon = totalMiles / totalGallons;
System.out.printf("Your total mileage for these trips is: %.2f.\nYour total gas consumed on these trips was: %.2f.\n", totalMiles, totalGallons);
System.out.printf("Your total mileage for these trips is: %.2f MPG", milesPerGallon);
}
}
里程测试.java：
package gasMileage;
public class Mileagetest
{
public static void main(String[] args)
{
Mileage myMileage = new Mileage(1,0,0,0,0,0);
myMileage.calculateMileage();
}
}
现在对于没有二传手和获取器的那个：
测试里程.java：
package gasMileage;
import java.util.Scanner;
public class Testmileage
{
int restart = 1;
double miles = 0, milesTotal = 0, gas = 0, gasTotal = 0, mpg = 0;
Scanner input = new Scanner(System.in);
public void testCalculate()
{
while(restart == 1)
{
System.out.print("Please input miles: ");
miles = input.nextDouble();
milesTotal = milesTotal + miles;
System.out.print("Please input gas: ");
gas = input.nextDouble();
gasTotal = gasTotal + gas;
mpg = miles/gas;
System.out.printf("MPG: %.2f", mpg);
System.out.print("\nContinue? 1 = yes, 2 = no: ");
restart = input.nextInt();
}
mpg = milesTotal / gasTotal;
System.out.printf("Total Miles: %.2f\nTotal Gallons: %.2f\nTotal MPG: %.2f\n", milesTotal, gasTotal, mpg);
}
}
Testmileagetest.java：
package gasMileage;
public class Testmileagetest
{
/**
* @param args
*/
public static void main(String[] args)
{
Testmileage test = new Testmileage();
test.testCalculate();
}
}
再次感谢！
