为什么 bufferedwriter 没有写入文件? [英] why is bufferedwriter not writing in the file?

问题描述

这是代码片段.

read = new FileReader("trainfiles/"+filenames[i]);
                br = new BufferedReader(read);
                while((lines = br.readLine())!=null){
                    st = new StringTokenizer(lines);
                    while(st.hasMoreTokens()){
                        bw = new BufferedWriter(new FileWriter("files/file.txt"));
                        bw.write(st.nextToken());
                        bw.newLine();
                    }
                }

我正在从目录中读取文件.所以，我需要在每个循环中打开阅读器.我做了一些修改，但它也没有写入该文件.代码如下:

I am reading files from a directory. So, I need to open the reader in every loop. I have made some modification, but then also it is not writing to that file. Here is the code:

for(i=0;i==0;i++){
            if(filenames[i].matches(".*ham.*")){
                System.out.println("ham:"+filenames[i]);
                read = new FileReader("trainfiles/"+filenames[i]);
                br = new BufferedReader(read);
                while((lines = br.readLine())!=null){
                    st = new StringTokenizer(lines);
                    while(st.hasMoreTokens()){
                        System.out.println(st.nextToken());
                       bw.write(st.nextToken());
                    }
                }
                bw.close();
                br.close();

            }else{
                System.out.println("spam:"+filenames[i]);
            }
                        }

我修改了代码，但是没有成功，

edit: I modified the code, but no success,

while((lines = br.readLine())!=null){
                    st = new StringTokenizer(lines);
                    bw = new BufferedWriter(new FileWriter("files/file.txt"));
                    while(st.hasMoreTokens()){
                        System.out.println(st.nextToken());
                       bw.write(st.nextToken());
                    }
                    bw.close();
                }

                br.close();

我收到此错误:线程main"中的异常 java.util.NoSuchElementException在 java.util.StringTokenizer.nextToken(StringTokenizer.java:332)在 Test.main(Test.java:30)

谢谢大家..我想通了.其实我在eclipse中创建了一个目录，我没有刷新它来查看内容.它很愚蠢......反正.非常感谢

edit: Thanks guys.. I figured it out. Actually I created an directory in eclipse and I did not refresh it to see the content. Its silly... anyways.thanks a lot

推荐答案

• 您正在循环内创建 FileWritter，因此您将始终在每个循环中截断文件.
• 您忘记关闭/刷新写入器
• 但幸运的是(终止程序可能会导致作者刷新)该文件将包含您输入文件的最后一个字，我只能猜测这将是一个新行，并且您在打开文件时可能错过了检查内容.

你的内部循环应该是这样的:

Your inner loop should be something like this:

try (BufferedWriter bw = new BufferedWriter(new FileWriter("file.txt"))) {
    while (st.hasMoreTokens()) {
        bw.write(st.nextToken());
        bw.newLine();
    }
}

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