从java文件更新文本文件

Question

public void updateF()throws Exception
{
    int i;
    BufferedWriter outputWriter = null;
    outputWriter = new BufferedWriter(new FileWriter(getClass().getResource("valS.txt").getFile()));
    for (i = 0; i < Status.length-1; i++) 
    {
            outputWriter.write(Status[i]+","); 
    }
    outputWriter.write(Status[i]);
    outputWriter.flush();  
    outputWriter.close(); 
}

我正在尝试更新一个文件“valS.txt”，其中显示了我的所有文件。存在java文件。此代码可编译但不更新任何内容。我认为这条路是走不到的。救命

Answer 1

outputWriter=new BufferedWriter（new FileWriter（valS.txt））

试着这样做，而不是： outputWriter=新的BufferedWriter（新的文件编写器（getClass（））。getResource（“valS.txt”）。getFile（））

Answer 2

         FileWritter, a character stream to write characters to file. By default, it will 
        replace all the  existing content with new content, however, when you specified a true (boolean)
        value as the second argument in FileWritter constructor, it will keep the existing content and 
        append the new content in the end of the file.
        fout = new FileWriter("filename.txt", true);
        the true is enabling append mode .

write Like:
BufferedWriter outputWriter = null;
outputWriter = new BufferedWriter(new FileWriter(getClass().getResource("valS.txt").getFile(),true));

Answer 3

假设您的状态数组不是空的，则此代码将起作用，但文件文本文件将在编译/输出目录中更新

因此，源目录中的文本文件不会被更新，但输出目录中的文本文件会被更新

还要注意，您正在使用的FileWirter的构造函数将覆盖文件的内容，因此您应该使用带有append参数的构造函数：

public FileWriter(String fileName, boolean append) throws IOException 

编辑：如果您确实需要更新src目录中的文件，可以这样做

不是很好，但这会管用的

public void updateF()throws Exception
{

    String fileName = "valS.txt";
    File fileInClasses = new File(getClass().getResource(fileName).getFile());
    System.out.println(fileInClasses.getCanonicalPath());
    File f = fileInClasses;
    boolean outDir = false;

    // let's find the output directory
    while(!outDir){
        f = f.getParentFile();
        outDir = f.getName().equals("out");
    }

    // get the parent one more time
    f = f.getParentFile();

    // from there you should find back your file
    String totoPath = f.getPath()+"/src/com/brol/" + fileName;
    File totoFile = new File(totoPath);

    BufferedWriter outputWriter = null;
    outputWriter = new BufferedWriter(new FileWriter(totoFile, true));
    outputWriter.append("test");
    outputWriter.flush();
    outputWriter.close();
}