How to return an encrypted zip file using Java Spring boot zip4j

Question

I want to generate a password protected zip file and then return to frontend. I am using spring boot and zip4j library. Able to generate zip file in backend service,but not able to send to frontend.

Service

import net.lingala.zip4j.ZipFile;
import net.lingala.zip4j.model.ZipParameters;
import net.lingala.zip4j.model.enums.CompressionLevel;
import net.lingala.zip4j.model.enums.EncryptionMethod;

public ZipFile downloadZipFileWithPassword(String password){
    
    String filePath="Sample.csv";
    
    ZipParameters zipParameters = new ZipParameters();
    zipParameters.setEncryptFiles(true);
    zipParameters.setCompressionLevel(CompressionLevel.HIGHER);
    zipParameters.setEncryptionMethod(EncryptionMethod.AES);
    ZipFile zipFile = new ZipFile("Test.zip", password.toCharArray());
    zipFile.addFile(new File(filePath), zipParameters);
    
    return zipFile;
}

Controller

import net.lingala.zip4j.ZipFile;

@GetMapping(value = "/v1/downloadZipFileWithPassword")
ResponseEntity<ZipFile> downloadZipFileWithPassword(@RequestParam("password")String password){
    
        ZipFile zipFile = service.downloadZipFileWithPassword(password);
        return ResponseEntity.ok().contentType(MediaType.parseMediaType("application/zip"))
                .header("Content-Disposition", "attachment; filename=\"Test.zip\"")
                .body(zipFile);
    
} 

In controller How can I convert this ZipFile (net.lingala.zip4j.ZipFile) to outputstream and send it to client ?

Answer 1

The below code worked for me.

import net.lingala.zip4j.ZipFile;

@GetMapping(value = "/v1/downloadZipFileWithPassword")
ResponseEntity<StreamingResponseBody> downloadZipFileWithPassword(@RequestParam("password") String password) {

    ZipFile zipFile = service.downloadZipFileWithPassword(password);
    return ResponseEntity.ok().contentType(MediaType.parseMediaType("application/zip"))
        .header("Content-Disposition", "attachment; filename=\"Test.zip\"")
        .body(outputStream -> {

            try (OutputStream os = outputStream; InputStream inputStream = new FileInputStream(zipFile.getFile())) {
                IOUtils.copy(inputStream, os);
            }
        });

}