java 将控制台输出到文本文件中？- 爪哇
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Output console into text file? - Java
提问by Alexander
Given my code:
鉴于我的代码：
import java.util.Scanner;
public class AccountTest {
public static void main(String[] args) {
Account account1 = new Account(50.00);
Account account2 = new Account(0.00);
System.out.printf("account1 balance: $%.2f\n", account1.getBalance());
System.out.printf("account2 balance: $%.2f\n\n", account2.getBalance());
Scanner input = new Scanner(System.in);
System.out.print("Enter withdrawal amount for account1: ");
double withdrawalAmount = input.nextDouble();
System.out.printf("\nsubtracting %.2f from account1 balance\n",
withdrawalAmount);
account1.debit(withdrawalAmount);
System.out.printf("account1 balance: $%.2f\n", account1.getBalance());
System.out.printf("account2 balance: $%.2f\n\n", account2.getBalance());
System.out.print("Enter withdrawal amount for account2: ");
withdrawalAmount = input.nextDouble();
System.out.printf("\nsubtracting %.2f from account2 balance\n",
withdrawalAmount);
account2.debit(withdrawalAmount);
System.out.printf("account1 balance: $%.2f\n", account1.getBalance());
System.out.printf("account2 balance: $%.2f\n", account2.getBalance());
}
}
How can I get my "System.out.printf" dumped into a file (dumped as in not erasing the file's content)? Or perhaps creating separate files for each instance. Any help is appreciated beginner here. Thanks.
如何将我的“System.out.printf”转储到文件中（转储为不擦除文件内容）？或者可能为每个实例创建单独的文件。任何帮助都感谢初学者在这里。谢谢。
回答by Evgeniy Dorofeev
1) you can redirect stdout to a file when running your program
1）您可以在运行程序时将标准输出重定向到文件
java AccountTest >> test.txt
2) you can reassign stdout at the beginning of your program
2）您可以在程序开始时重新分配标准输出
PrintStream out = new PrintStream(new FileOutputStream("test.txt", true));
System.setOut(out);
3) you can use java.io.PrintWriter instead of System.out
3) 你可以使用 java.io.PrintWriter 而不是 System.out
PrintWriter out = new PrintWriter(new FileWriter("test.txt", true));
out.printf( "account1 balance: $%.2f\n", account1.getBalance() );
回答by Nowhere man
It depends on how you run this program. If you have a POSIX shell at hand, you can just redirect its standard output to a file.
这取决于你如何运行这个程序。如果您手头有 POSIX shell，您可以将其标准输出重定向到一个文件。
The following would append to a log file:
以下内容将附加到日志文件中：
$ java -jar myjar.jar >> log
this one would create a new epoch-dated log file each time (the $(…)might be a bash-specific feature, I'm not sure):
这个每次都会创建一个新的纪元日志文件（这$(…)可能是一个特定于 bash 的功能，我不确定）：
$ java -jar myjar.jar > log-$(date +%s)
