Zipping a csv file throws a "At Least One ZipEntry" using Java

Question

What I am trying to do is to zip a generated csv file. The file does get generated without issue until it comes to this code here. So the code throws the exception at zos.close() here's the code

try {
    FileOutputStream fos = new FileOutputStream(file.getPath());
    ZipOutputStream zos = new ZipOutputStream(fos);
    FileInputStream in = new FileInputStream(file.getPath());
    String fullCSVFileName = file.getName();
    String fullFileName = fullCSVFileName.substring(0, fullCSVFileName.length()-3);
    String fullZipFileName = fullFileName + "zip";
    ZipEntry ze= new ZipEntry(fullZipFileName);
    if(ze != null) zos.putNextEntry(ze);
    fos = new FileOutputStream("C:\\sourceLocation\\"+fullZipFileName);
    zos = new ZipOutputStream(fos);

    byte[] buffer = new byte[1024];

    int len;// = in.read(buffer);
    while ((len = in.read(buffer)) > 0) {
        Logger.debug("in Loop, len = " + len);
        zos.write(buffer, 0, len);
    }
    in.close();
    zos.closeEntry();    
    zos.close();

    Logger.debug("Zipping complete!");

} catch(IOException ex) {
    Logger.error(ex);
}

Corrected Code

try{

    String fullCSVFileName = file.getName();
    String fullFileName = fullCSVFileName.substring(0, fullCSVFileName.length()-3);                     
    String fullZipFileName = fullFileName + "zip";                      
    FileOutputStream fos = new FileOutputStream("C:\\sourceLocation\\"+fullZipFileName);
    ZipOutputStream zos = new ZipOutputStream(fos);
    FileInputStream in = new FileInputStream(file.getPath());

    ZipEntry ze= new ZipEntry(fullZipFileName);
    if(ze != null){
        zos.putNextEntry(ze);
    }

    byte[] buffer = new byte[1024];

    int len;    
    while ((len = in.read(buffer)) > 0) {
        zos.write(buffer, 0, len);
    }

    in.close();
    zos.closeEntry();
    zos.close();

    Logger.debug("Zipping complete!");

}catch(IOException ex){
    Logger.error(ex);
}

Answer 1

You create fos and zos once at the top of your code:

FileOutputStream fos = new FileOutputStream(file.getPath());
ZipOutputStream zos = new ZipOutputStream(fos);

then add a ZipEntry:

if(ze != null) zos.putNextEntry(ze);

then redifine them later:

fos = new FileOutputStream("C:\\sourceLocation\\"+fullZipFileName);
zos = new ZipOutputStream(fos);

then close the new zos. You never closed, nor wrote to the first zos (which had a ZipEntry) and never added a ZipEntry to the second (which you tried to close without any). Hence, the At Least One ZipEntry error.

------------ Edit --------------

Try adding zos.finish(), also, your close() methods should be in a finally block...

ZipOutputStream zos = null;
FileInputStream in = null;
try{

    String fullCSVFileName = file.getName();
    String fullFileName = fullCSVFileName.substring(0, fullCSVFileName.length()-3);                     
    String fullZipFileName = fullFileName + "zip";                      
    ZipOutputStream zos = new ZipOutputStream(
            new FileOutputStream("C:\\sourceLocation\\"+fullZipFileName));
    in = new FileInputStream(file.getPath());

    zos.putNextEntry( new ZipEntry(fullZipFileName) );

    byte[] buffer = new byte[1024];

    int len;    
    while ((len = in.read(buffer)) > 0) {
        zos.write(buffer, 0, len);
    }

    zos.finish();

    Logger.debug("Zipping complete!");

}catch(IOException ex){
    Logger.error(ex);
}finally {
    if ( zos != null ) {
        try {
            zos.close();
        } catch ( Exception e ) {}
    }
    if ( in != null ) {
        try {
            in.close();
        } catch ( Exception e ) {}
    }
}