Question

我正面临文件写入问题，实际上当我运行下面的代码时，while循环迭代无限次。

package com.demo.io;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class CopyFile {

    public static void main(String[] args) {

        FileInputStream in = null;
        FileOutputStream out = null;
        try {
            in = new FileInputStream("C:/Users/s.swain/Desktop/loginissue.txt");
            out = new FileOutputStream("C:/Users/s.swain/Desktop/output.txt");
            int c = in.read();
            while (c != -1) {
                System.out.println(c);
                out.write(c);
            }

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

任何人都可以告诉我如何写这个文件。

由于

Sitansu

Answer 1

此条件永久true永久为真，因为您永远不会更新c中的while-loop：

while (c != -1) {

在 in.read内使用while-loop ！

int c = in.read(); while (c != -1) { System.out.println(c); out.write(c); c = in.read(); }

Answer 2

您错过了阅读下一个字节：

int c = in.read();
while (c != -1) {
    System.out.println(c);
    out.write(c);
    c = in.read();//this line added to read next byte
}

或者，你可以简单地使用：

int c;
while (-1 != (c = in.read())) { /* condition with assignment */
    out.write(c);
}

Answer 3

您只能阅读c一次。将你的while循环更新为

while (c != -1) {
    System.out.println(c);
    out.write(c);
    c = in.read();
}

Answer 4

尝试这样的事情：

        while(c != null){
            System.out.println(c);
            out.write(c);
            c = reader.readLine();
        }

Answer 5

就这样做

toArray

Answer 6

while (c != -1) {
                System.out.println(c);
                out.write(c);
            }

如果c！= -1，你认为会发生什么？你没有更新c的值，所以它会导致无限循环。

如何在java中写文件？

6 个答案: