java循環寫入檔案,Java寫入檔案。使用循環

I have a simple application that yet would trash a text file (it's just practice) I'm only 3 days with Java yet. Problem is there are no errors until you run the program then it throws an exception and stops. Thank you.

This is the exception:

java.io.IOException: Stream closed

at sun.nio.cs.StreamEncoder.ensureOpen(Unknown Source)

at sun.nio.cs.StreamEncoder.write(Unknown Source)

at java.io.OutputStreamWriter.write(Unknown Source)

at java.io.Writer.write(Unknown Source)

at test.main(test.java:18)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)

And this is the code.

import java.io.FileWriter;

import java.util.Random;

import java.io.IOException;

public class test {

public static void main(String[] args) throws IOException {

final String alphabet = "abcdefghigklmnopqrstuvwxyz";

final int N = alphabet.length();

Random r = new Random();

FileWriter file = new FileWriter("hello.txt");

String sb = " ";

for (int i = 0; i < 1;) {

sb += alphabet.charAt(r.nextInt(N));

System.out.println(sb);

int length = sb.length();

file.write(sb);

file.close();

if (length == 30) {

sb = " ";

}

解決方案

The problem is that you are closing your FileWriter and trying to use it again.

Instead, close the writer after you've finished the loop:

try (FileWriter file = new FileWriter("hello.txt")) {