Exemplo de download de arquivo utilizando OkHttp - Example of file download using OkHttp

.SampleDownloadFileOkHttp.java

import me.tongfei.progressbar.ProgressBar;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class SampleDownloadFileOkHttp {
    //*
    private static final String HEADER_AUTHORIZATION = "Authorization";
    private static final String HEADER_CONTENT_LENGTH = "Content-Length";
    private static final String HEADER_CONTENT_DISPOSITION = "Content-Disposition";
    //*
    private static final String FILE_JBOSS = "http://helpdev.com.br/file/15BB358C8E497C0C2BD0B594A1470D84527D75EB/15";
    private static final String TOKEN = "Bearer eyJzdWIiOiJudGFsayIsInByaXZpbGVnZXMiOlsiUk9MRV9VU0VSIl19.-nSEkcSbEW4SmXqQ";

    public static void main(String[] args) throws IOException {
        Request request = new Request.Builder().url(FILE_JBOSS)
                .header(HEADER_AUTHORIZATION, TOKEN)
                .get().build();

        new SampleDownloadFileOkHttp().sampleDownloadOkHttp(request, new File("/home/helpdev"));
    }

    private void sampleDownloadOkHttp(Request request, File pathToSaveFile) throws IOException {
        OkHttpClient okHttpClient = new OkHttpClient();

        Response response = okHttpClient.newCall(request).execute();
        if (response.body() == null) {
            throw new IOException("no body");
        }

        String headerContentLength = response.header(HEADER_CONTENT_LENGTH);

        final long lengthFile;
        if (headerContentLength != null && !headerContentLength.isEmpty()) {
            lengthFile = Integer.parseInt(headerContentLength);
        } else {
            lengthFile = -1;
        }

        String fileName = System.currentTimeMillis() + ".tmp";
        String headerContentDisposition = response.header(HEADER_CONTENT_DISPOSITION);
        if (headerContentDisposition != null) {
            Pattern regex = Pattern.compile("(?<=filename=\").*?(?=\")");
            Matcher regexMatcher = regex.matcher(headerContentDisposition);
            if (regexMatcher.find()) {
                fileName = regexMatcher.group();
            }
        }

        File fileToSave = new File(pathToSaveFile, fileName);
        try {
            final ProgressBar progressBar = new ProgressBar(fileName + " downloading...", lengthFile);
            progressBar.start();

            saveStreamToFile(response.body().byteStream(), fileToSave, progressBar::stepTo);

            progressBar.stop();

        } catch (IOException io) {
            fileToSave.deleteOnExit();
        }
    }


    public interface DownloadNotify {
        void downloading(long total);
    }


    private void saveStreamToFile(InputStream inputStream,
                                  File fileToSave,
                                  DownloadNotify downloadNotify) throws IOException {
        saveStreamToFile(inputStream, fileToSave, downloadNotify, 131072, 3_000);
    }

    private void saveStreamToFile(InputStream inputStream,
                                  File fileToSave,
                                  DownloadNotify downloadNotify,
                                  int sizeBuffer,
                                  int notifyTimeMillis) throws IOException {
        try (BufferedInputStream input = new BufferedInputStream(inputStream);
             OutputStream output = new FileOutputStream(fileToSave)) {

            byte[] data = new byte[sizeBuffer];

            long total = 0;

            long notify = System.currentTimeMillis();

            int count;
            while ((count = input.read(data)) != -1) {
                total += count;

                if ((System.currentTimeMillis() - notify) > notifyTimeMillis) {
                    downloadNotify.downloading(total);
                    notify = System.currentTimeMillis();
                }

                output.write(data, 0, count);
            }

            downloadNotify.downloading(total);
            output.flush();
        }
    }
    
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>teste</groupId>
    <artifactId>teste</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>3.12.0</version>
        </dependency>

        <dependency>
            <groupId>me.tongfei</groupId>
            <artifactId>progressbar</artifactId>
            <version>0.7.1</version>
        </dependency>


    </dependencies>

</project>