如何在 Java 中使用 FileWriter 写入新行？
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How do I write to a new line using FileWriter in Java?
提问by kr4m
I've been trying to make a simple bank account in Java and want to save the inputted users' name into a .txt doc. Only problem is that the name is replaced on the first line of the text doc each time I run the code.
我一直在尝试用 Java 创建一个简单的银行帐户，并希望将输入的用户名保存到 .txt 文档中。唯一的问题是，每次运行代码时，文本文档的第一行的名称都会被替换。
package bank.account;
import java.util.Scanner;
import java.io.*;
public class ATM
{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
BankAccount userAccount = new BankAccount();
System.out.println("Please enter your name in order to make a new account:");
String fileName = "name.txt";
try {
FileWriter fileWriter =
new FileWriter(fileName);
BufferedWriter bufferedWriter =
new BufferedWriter(fileWriter);
String name = sc.nextLine();
userAccount.setaccName(name);
bufferedWriter.write(userAccount.getaccName());
bufferedWriter.close();
}
catch(IOException ex) {
System.out.println(
"Error writing to file '"
+ fileName + "'");
}
System.out.println("Please enter the amount you would like to deposit");
double money = sc.nextDouble();
userAccount.deposit(money);
System.out.println(userAccount.getaccBalance());
System.out.println(userAccount.getaccName()+ " your balance is " + userAccount.getaccBalance());
}
}
采纳答案by Thomas
You're overwriting the file contents due to the use of new FileWriter(fileName);(read the JavaDoc on that class/constructor). Use new FileWriter(fileName, true);to appendto the file instead.
由于使用new FileWriter(fileName);（阅读该类/构造函数上的 JavaDoc），您正在覆盖文件内容。使用new FileWriter(fileName, true);以附加到文件来代替。
Also note that you'd need to append a newline character ("\n") before the name if the file is not empty otherwise you'll get all the names in one line.
另请注意，"\n"如果文件不为空，则您需要在名称前附加一个换行符 ( )，否则您将在一行中获得所有名称。
回答by LenglBoy
This Code will open or create a file and append the new text into a new line.
此代码将打开或创建一个文件并将新文本附加到新行中。
PrintStream fileStream = new PrintStream(new File("a.txt"));
fileStream.println(userAccount.getaccName());
Also you can create the FileWriterwith the param "append = true" and then the outcome will just be appended into a new line.
您也可以FileWriter使用参数“ append = true”创建，然后结果将被附加到一个新行中。
// FileWriter(File file, boolean append)
FileWriter fileWriter =
new FileWriter(filePathName, shouldAppend);
