java 资源泄漏输入永远不会关闭 - 我在哪里/何时关闭以及如何关闭？
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Resource leak input is never closed - where/when do i close and how?
提问by Devin Wesolowski
I tried closing it but i'm not sure where to put the input.close();, im really new to all this and asking my professors risks me losing points. Also i'm not sure if i should keep the second to last system.out monthly payment is, or get rid of it. Does it even make sense with the rest of my code?
我试着关闭它，但我不知道把 input.close(); 放在哪里，我对这一切真的很陌生，问我的教授有失去积分的风险。此外，我不确定我是否应该保留倒数第二个 system.out 每月付款，或者摆脱它。它甚至对我的其余代码有意义吗？
import java.util.Scanner;
public class Project2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
//Yearly interest rate
System.out.print("Enter annual interest rate, for example 0.5, no percent sign:");
double annualInterestRate = input.nextDouble();
//Monthly interest rate
double monthlyInterestRate = annualInterestRate / 1200;
//Number of years
System.out.print("Enter number of years, for example 5: ");
int numberOfYears = input.nextInt() ;
//Loan amount
System.out.print("Enter investment amount, for example 145000.95: ");
double loanAmount = input.nextDouble();
//Calculate payments
double monthlyPayment = loanAmount * monthlyInterestRate / (1
- 1 / Math.pow(1 + monthlyInterestRate, numberOfYears * 12));
double totalPayment = monthlyPayment * numberOfYears * 12;
System.out.println("The monthly payment is " +
(int) (monthlyPayment * 100) / 100.0);
System.out.println("Accumulated value is " +
(int) (totalPayment * 100) / 100.0);
回答by Jean Logeart
Simply use a try-with-resourcesstatement:
只需使用try-with-resources语句：
try (Scanner input = new Scanner(System.in)) {
// code using input
}
回答by Mureinik
Traditionally, you should put the close()call in a finallyblock so it's called regardless of any exception you'd have on the way:
传统上，您应该将close()调用放在一个finally块中，以便无论您遇到任何异常都会调用它：
Scanner input = new Scanner(System.in);
try {
// Use input
} finally {
input.close();
}
However, since Scanner is AutoClosable, Java 7 offers a cleaner syntax to do this:
但是，由于 Scanner 是 AutoClosable，Java 7 提供了更简洁的语法来执行此操作：
try (Scanner input = new Scanner(System.in)) {
// Use input
}
回答by Deepak
Just add input.close when you are done using the Scanner class
使用 Scanner 类完成后只需添加 input.close
