重用FileOutputStream时应该关闭流吗？

如标题所述，重用FileOutputStream变量时是否应该关闭流？例如，在以下代码中，我应outfile.close()在分配新文件之前调用，为什么？

谢谢：）

FileOutputStream outfile = null;
int index = 1;

while (true) {

    // check whether we should create a new file
    boolean createNewFile = shouldCreateNewFile();

    //write to a new file if pattern is identified
    if (createNewFile) {
        /* Should I close the outfile each time I create a new file?
        if (outfile != null) {
            outfile.close();
        }
        */
        outfile = new FileOutputStream(String.valueOf(index++) + ".txt");
    }

    if (outfile != null) {
        outfile.write(getNewFileContent());
    }

    if (shouldEnd()) {
        break;
    }
}

try {
    if (outfile != null) {
        outfile.close();
    }
} catch (IOException e) {
    System.err.println("Something wrong happens...");
}