為什么在此代碼中出現java.io.FileNotFoundException錯誤和java.lang.NullPointerException？

Question

這是我的代碼段：

public class Compress {
    List<String> filesinDir= new ArrayList<String>();

public static void main(String[] args){

   Compress c= new Compress();
   c.gzipFile();
   String OUTPUT_DIR= "C:\\Users\\Surya's\\Documents\\tmp.zip";
   File dir= new File(" C:\\Users\\Surya's\\Documents\\tmp ");
   c.zipDirectory(dir, OUTPUT_DIR);
 }

public void gzipFile(){

   String OUTPUT_GZIP_FILE= " C:\\Users\\Surya's\\Documents\\file1.gz ";
   String SOURCE_FILE= " C:\\Users\\Surya's\\Documents\\file1.txt ";
   byte[] b= new byte[1024];
   int len;

   try{
   FileOutputStream fos= new FileOutputStream(OUTPUT_GZIP_FILE);
   GZIPOutputStream gz= new GZIPOutputStream(fos);
   FileInputStream in= new FileInputStream(SOURCE_FILE);
      while((len= in.read(b))!= -1){
          gz.write(b, 0, len);
      }
      fos.close();
      in.close();
      gz.finish();
      gz.close();
   }

   catch(IOException e){
       e.printStackTrace();
   }
}

public void zipDirectory(File dir, String OUTPUT_DIR){
   try{
       ListofFiles(dir);
       FileOutputStream of= new FileOutputStream(OUTPUT_DIR);
       ZipOutputStream gzdir= new ZipOutputStream(of);
       for(String filepath : filesinDir){
           ZipEntry ze= new     ZipEntry(filepath.substring(dir.getAbsolutePath().length()+1, filepath.length()));
           gzdir.putNextEntry(ze);
           byte[] b= new byte[1024];
           int len;
           FileInputStream fi= new FileInputStream(filepath);
           while((len=fi.read(b))!=-1){
               of.write(b, 0, len);
           }
           gzdir.closeEntry();
           fi.close();
       }
       gzdir.close();
       of.close();
   }
   catch(IOException e){
       e.printStackTrace();
   }
}

public  void ListofFiles(File dir) throws IOException{
   File[] files= dir.listFiles();
   for(File file : files){
       if(file.isFile()) filesinDir.add(file.getAbsolutePath());
       else ListofFiles(file);
    }
  }
}

我正在嘗試壓縮單個文件以及其中包含文件的目錄。 gzipFile（）處理單個文件的壓縮，而zipDirectory（）調用函數ListofFiles（）來在數組中排列抽象路徑名。 zipDirectory使用ZipEntry從文件的開頭開始寫入，並定位文件的開頭。

錯誤消息是

java.io.FileNotFoundException:  C:\Users\Surya's\Documents\file1.gz  (The filename, directory name, or volume label syntax is incorrect)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:221)
at java.io.FileOutputStream.<init>(FileOutputStream.java:110)
at com.assignment.java.Compress.gzipFile(Compress.java:29)
at com.assignment.java.Compress.main(Compress.java:15)
Exception in thread "main" java.lang.NullPointerException
at com.assignment.java.Compress.ListofFiles(Compress.java:73)
at com.assignment.java.Compress.zipDirectory(Compress.java:48)
at com.assignment.java.Compress.main(Compress.java:18)

為什么會顯示FileNotFound異常，因為該程序應該在Documents文件夾中創建文件file1.gz。

Answer 1

您不應在路徑上放置多余的空格。

嘗試使用

String OUTPUT_DIR= "C:\\Users\\Surya's\\Documents\\tmp.zip";
File dir= new File("C:\\Users\\Surya's\\Documents\\tmp");

String OUTPUT_GZIP_FILE= "C:\\Users\\Surya's\\Documents\\file1.gz";
String SOURCE_FILE= "C:\\Users\\Surya's\\Documents\\file1.txt";

代替

String OUTPUT_DIR= "C:\\Users\\Surya's\\Documents\\tmp.zip";
File dir= new File(" C:\\Users\\Surya's\\Documents\\tmp ");

String OUTPUT_GZIP_FILE= " C:\\Users\\Surya's\\Documents\\file1.gz ";
String SOURCE_FILE= " C:\\Users\\Surya's\\Documents\\file1.txt ";