Download a file from Springboot REST service

Download a file from Springboot REST service

I was working on Hbase REST API to download ingested file from table which is JSON Response this response need to be downloaded as a JSON file from the UI either single file or user can download multiple files as zip . I created a rest service which downloads single and selected multiple files as ZIP file. This my first article please share your comments and inputs thanks for reading

Below is my input and I need to download as JSON file

input data

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class HbaseRestController {
@RequestMapping(value = “/files/{file_name}”, method = RequestMethod.GET)
public void getFile(
@PathVariable(“file_name”) String fileName,
HttpServletResponse response) {
String testJson=”{\\r\\n \\\”name\\\”: \\\”Jungle Gym\\\”,\\r\\n \\\”age\\\”: 25\\r\\n}”;
try {
// get your file as InputStream
InputStream is = new ByteArrayInputStream(testJson.getBytes());
// copy it to response’s OutputStream
org.apache.commons.io.IOUtils.copy(is, response.getOutputStream());
String filename=”attachment;”+”filename=”+fileName;
response.setContentType(“application/json”);
response.setHeader(“Content-Disposition”, “attachment; filename=”+filename+”.json”);
response.flushBuffer();
System.out.println(“Filename — — — — — ->”+ fileName);
} catch (IOException ex) {
System.out.println(“Error writing file to output stream. Filename was “+ fileName+”==>”+ex);
throw new RuntimeException(“IOError writing file to output stream”);
}

}

@RequestMapping(value =”/downLoadZIPFile”, method = RequestMethod.GET)
public void downLoadSearchFiles(HttpServletResponse response)
{

Map<String, String> jsonList= new HashMap<>();
jsonList.put(“F101”, “{\\r\\n \\\”name\\\”: \\\”TEst\\\”,\\r\\n \\\”age\\\”: 25\\r\\n}”);
jsonList.put(“F102”, “{\\r\\n \\\”name\\\”: \\\”Jungle Gym\\\”,\\r\\n \\\”age\\\”: 26\\r\\n}”);
jsonList.put(“F103”, “{\\r\\n \\\”name\\\”: \\\”Jungle Gym\\\”,\\r\\n \\\”age\\\”: 27\\r\\n}”);

try{
response.setHeader(“Pragma”, “public”);
response.setHeader(“Expires”, “0”);
response.setHeader(“Cache-Control”, “must-revalidate, post-check=0, pre-check=0”);
response.setHeader(“Content-type”, “application-download”);
response.setHeader(“Content-Disposition”, “attachment; filename=-JSONSearchResultsData-”+new SimpleDateFormat(“yyyyMMdd”).format(new Date())+”.zip”);
response.setHeader(“Content-Transfer-Encoding”, “binary”);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ZipOutputStream zipOutputStream = new ZipOutputStream(baos);
for (Entry<String, String> entry : jsonList.entrySet()) {
ZipEntry e = new ZipEntry(entry.getKey()+new SimpleDateFormat(“yyyyMMdd”).format(new Date())+”.”+”json”);
e.setSize(entry.getValue().length());
e.setTime(System.currentTimeMillis());
zipOutputStream.putNextEntry(e);

InputStream is = new ByteArrayInputStream(entry.getValue().getBytes());
IOUtils.copy(is, zipOutputStream);
is.close();
zipOutputStream.closeEntry();
}
zipOutputStream.close();

byte[] zipBytes = baos.toByteArray();
OutputStream outStream = response.getOutputStream();
outStream.write(zipBytes);
outStream.close();
response.flushBuffer();
}catch(Exception e)
{
}
}
}