How to ZIP a JAVA CSV file and manage it in a Byte array

◆ Main class

	public static void main(String[] args) {

		List<File> csvFileList = new ArrayList<File>();
		CsvCreater csvCreater = new CsvCreater();

		for (int i = 0; i < 5; i++) {
			csvFileList.add(csvCreater.createCsv());
		}

		//Convert CSV to Byte array
		ZipFileUtil zipFileUtil = new ZipFileUtil();
		String zipFileName = zipFileUtil.createZip(csvFileList);
		byte[] zipByteArray = zipFileUtil.zipToByteArray(zipFileName);

		//Restore Byte array to ZIP
		EncodeZip encodeZip = new EncodeZip();
		encodeZip.write(zipByteArray);
	}

◆CSVCreater.java

public class CsvCreater {
	private Integer num = 0;

	public CsvCreater() {
		//TODO auto-generated constructor stub
	}

	public File createCsv() {
		File csvFile = null;
		CSVWriter csvw = null;
		num += 1;
		try {
			csvFile = createFile(num);
			csvw = new CSVWriter(new FileWriter(csvFile), ",".charAt(0),
					"\"".charAt(0), "\"".charAt(0), "\r\n");

			List<String[]> outStrList = createDate();
			csvw.writeAll(outStrList);

			if (csvw != null) {
				csvw.close();
			}
			System.out.println("Successful processing");

		} catch (IOException e) {
			System.out.println("Processing failure");
			e.printStackTrace();
		} finally {
		}
		return csvFile;

	}

	public File createFile(Integer num) {
		Calendar cTime2 = Calendar.getInstance();
		String csvFileName = "tmp/csvFile" + cTime2.get(Calendar.SECOND) + "_" + num + ".csv";
		num = num + 1;
		return new File(csvFileName);
	}

	public List<String[]> createDate() {
		List<String[]> outDateList = new ArrayList<String[]>();
		String[] outStr = new String[100];
		Integer numnum;
		for (int k = 0; k < 5; k++) {
			for (int j = 0; j < 100; j++) {
				numnum = j * k;
				outStr[j] = numnum.toString();
			}
			outDateList.add(outStr);
		}
		return outDateList;
	}

}

◆ Zip file Utill class

package csv;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Calendar;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class ZipFileUtil {

	public String createZip(List<File> fileList) {
		ZipOutputStream zos = null;
		Calendar cTime = Calendar.getInstance(); //[1]
		String zipFileName = "tmp/zipfile" + cTime.get(Calendar.SECOND) + ".zip";
		File file = new File(zipFileName);

		try {
			zos = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(file)));
			createZip2(zos, fileList);

			fileSizeCheck(file);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return zipFileName;
	}

	public void createZip2(ZipOutputStream zos, List<File> fileList) throws IOException {
		byte[] buf = new byte[1024];
		InputStream is = null;
		try {
			for (File file : fileList) {
				ZipEntry entry = new ZipEntry(file.getName());
				zos.putNextEntry(entry);
				is = new BufferedInputStream(new FileInputStream(file));
				int len = 0;
				while ((len = is.read(buf)) != -1) {
					zos.write(buf, 0, len);
				}
			}

			is.close();
			zos.closeEntry();
		} catch (IOException e) {
			e.printStackTrace();
		}
		zos.close();

	}

	public void fileSizeCheck(File file) {
		long fileSize = file.length() / 1024;
		if (fileSize > 0) {
			System.out.println("File:" + file.getName());
			System.out.println("file size:" + fileSize + "KB");

		} else {
			System.out.println("Illegal file: 1KB");

		}

	}

	public byte[] zipToByteArray(String zipFileName) {
		File file = new File(zipFileName);
		try {
			InputStream inputStream = new FileInputStream(file);

			return getBytes(inputStream);

		} catch (FileNotFoundException e) {
			//TODO auto-generated catch block
			e.printStackTrace();
		}
		return null;

	}

	/**
	*Convert InputStream to byte array
	*
	* @param is
	* @return byte array
	*/
	public byte[] getBytes(InputStream is) {
		//A class whose output destination is a byte type array.
		//Normally, the byte output stream is output to a file or socket,
		//ByteArrayOutputStream class is byte[]The output destination is a variable, that is, memory.
		ByteArrayOutputStream b = new ByteArrayOutputStream();
		OutputStream os = new BufferedOutputStream(b);
		int c;
		try {
			while ((c = is.read()) != -1) {
				os.write(c);
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (os != null) {
				try {
					os.flush();
					os.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}

		//The write destination is inside the ByteArrayOutputStream class.
		//When extracting this written byte data as a byte type array,
		// toByteArray()Call the method.
		return b.toByteArray();
	}
}
```

◆EncodeZip

```java
package csv.day0114;

import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class EncodeZip {

	public EncodeZip() {
		//TODO auto-generated constructor stub
	}

	public void write(byte[] byteData) {

		File outputImageFile = new File("tmp/outfile2.zip");
		InputStream inputStream = new ByteArrayInputStream(byteData);

		OutputStream os = null;
		try {
			os = new BufferedOutputStream(new FileOutputStream(outputImageFile));
			int c;
			while ((c = inputStream.read()) != -1)
				os.write(c);
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (os != null) {
				try {
					os.flush();
					os.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}

			if (inputStream != null) {
				try {
					inputStream.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
}
```

 ◆ Directory deletion (recursive)

```java
	public void dirDelete(File TestFile) {
		if (TestFile.exists()) {

			//File existence check
			if (TestFile.isFile()) {
				//Delete if it exists
				if (TestFile.delete()) {
					System.out.println("File deletion:" + TestFile.getName());
					this.j++;
				} else {
					System.out.println("File does not exist:" + TestFile.getName());
				}
				//If the target is a directory
			} else if (TestFile.isDirectory()) {

				//Get the list in the directory
				File[] files = TestFile.listFiles();

				//Loop through the number of existing files and delete recursively
				for (int i = 0; i < files.length; i++) {
					dirDelete(files[i]);
				}
				System.out.println("Target to be deleted:" + files.length + "Number of deletions:" + this.j);

			}
		} else {
			System.out.println("Directory does not exist");
		}
	}
```