shz.spring.DownloadHelp Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of spring-bean
${project.artifactId}
There is a newer version: 2023.2.5
package shz.spring;

import shz.core.PRException;
import shz.core.io.IOHelp;

import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;
import java.util.Objects;

public final class DownloadHelp {
    private DownloadHelp() {
        throw new IllegalStateException();
    }

    public static void download(HttpServletResponse response, InputStream is, long offset) {
        Objects.requireNonNull(response);
        Objects.requireNonNull(is);
        try (OutputStream os = response.getOutputStream()) {
            IOHelp.read(is, Math.max(0, offset), 0L, os, IOHelp.DEFAULT_DATA_SIZE, null, null);
        } catch (IOException e) {
            throw PRException.of(e);
        }
    }

    public static void download(String contentType, String filename, InputStream is, long offset) {
        Objects.requireNonNull(contentType);
        Objects.requireNonNull(filename);
        Objects.requireNonNull(is);
        HttpServletResponse response = ServletHelp.getResponse();
        Objects.requireNonNull(response);
        try (OutputStream os = response.getOutputStream()) {
            offset = Math.max(0, offset);
            response.setContentLength(is.available() - (int) offset);
            response.setContentType(contentType);
            response.setHeader("Content-Disposition", "attachment; filename=" + filename);
            IOHelp.read(is, offset, 0L, os, IOHelp.DEFAULT_DATA_SIZE, null, null);
        } catch (IOException e) {
            throw PRException.of(e);
        }
    }

    public static void download(HttpServletResponse response, FileInputStream fis, long offset) {
        Objects.requireNonNull(response);
        Objects.requireNonNull(fis);
        try (OutputStream os = response.getOutputStream();
             WritableByteChannel wbc = Channels.newChannel(os);
             FileChannel fc = fis.getChannel()) {
            offset = Math.max(0L, offset);
            long size = fc.size() - offset;
            if (size > 0L) {
                fc.transferTo(offset, size, wbc);
                os.flush();
            }
        } catch (IOException e) {
            throw PRException.of(e);
        }
    }

    public static void download(String contentType, String filename, FileInputStream fis, long offset) {
        Objects.requireNonNull(contentType);
        Objects.requireNonNull(filename);
        Objects.requireNonNull(fis);
        HttpServletResponse response = ServletHelp.getResponse();
        Objects.requireNonNull(response);
        try (OutputStream os = response.getOutputStream();
             WritableByteChannel wbc = Channels.newChannel(os);
             FileChannel fc = fis.getChannel()) {
            offset = Math.max(0L, offset);
            long size = fc.size() - offset;
            if (size > 0L) {
                response.setContentLength((int) size);
                response.setContentType(contentType);
                response.setHeader("Content-Disposition", "attachment; filename=" + filename);
                fc.transferTo(offset, size, wbc);
                os.flush();
            }
        } catch (IOException e) {
            throw PRException.of(e);
        }
    }

    public static void download(String contentType, String filename, File file, long offset) {
        try {
            download(contentType, filename, new FileInputStream(file), offset);
        } catch (FileNotFoundException e) {
            throw PRException.of(e);
        }
    }
}