Java - 解压和进度条

Question

我的程序使用 JavaFX 中的任务来下载和解压缩文件，并通过使用 updateProgress(workDone, max) 方法和 progressProperty().bind 在屏幕上显示进度(可观察) 方法。它适用于下载:

package com.franckyi.lan.installer;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.file.Files;
import java.nio.file.Paths;

import javafx.concurrent.Task;

public class DownloadTask extends Task<Void> {

    private String file;
    private String url;

    public DownloadTask(String dir, String fileurl) {
        file = dir;
        url = fileurl;
    }

    @Override
    protected Void call() throws Exception {
        URLConnection connection = new URL(url).openConnection();
        long fileLength = connection.getContentLengthLong();

        try (InputStream is = connection.getInputStream();
                OutputStream os = Files.newOutputStream(Paths.get(file))) {

            long nread = 0L;
            byte[] buf = new byte[1024];
            int n;
            while ((n = is.read(buf)) > 0) {
                os.write(buf, 0, n);
                nread += n;
                updateProgress(nread, fileLength);
            }
        }
        return null;
    }

    @Override
    protected void succeeded(){
        System.out.println("Download succeeded");
    }

}

但它对于 Unzip 效果不佳:文件已正确解压缩，但我得到了错误的 ProgressBar(最后为空)。

package com.franckyi.lan.installer;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import javafx.concurrent.Task;

public class UnZipTask extends Task<Void>{

    private File zipfile;
    private File folder;

    public UnZipTask(File zipfile, File folder){
        this.zipfile = zipfile;
        this.folder = folder;
    }

    @Override
    protected Void call() throws Exception {
        ZipInputStream zis = new ZipInputStream(
            new BufferedInputStream(new FileInputStream(zipfile.getCanonicalFile())));
        ZipEntry ze = null;
        try {
            while ((ze = zis.getNextEntry()) != null) {
                 File f = new File(folder.getCanonicalPath(), ze.getName());
                if (ze.isDirectory()) {
                    f.mkdirs();
                    continue;
                }
                f.getParentFile().mkdirs();
                OutputStream fos = new BufferedOutputStream(new FileOutputStream(f));
                try {
                    try {
                        final byte[] buf = new byte[1024];
                        int bytesRead;
                        long nread = 0L;
                        long length = zipfile.length();

                        while (-1 != (bytesRead = zis.read(buf))){
                            fos.write(buf, 0, bytesRead);
                            nread += bytesRead;
                            System.out.println(nread + "/" + length);
                            updateProgress(nread, length);
                        }
                    } finally {
                        fos.close();
                    }
                } catch (final IOException ioe) {
                    f.delete();
                    throw ioe;
                }
            }
        } finally {
            zis.close();
        }
        return null;
    }

    @Override
    protected void succeeded(){
        System.out.println("Unzip succeeded");
    }

}

这是我在控制台中得到的内容:

Download succeeded
1024/91804
2048/91804
2815/91804
362/91804
326/91804
290/91804
386/91804
257/91804
250/91804
588/91804
1101/91804
1613/91804
2128/91804
2646/91804
3159/91804
3672/91804
4185/91804
4701/91804
5214/91804
5731/91804
6243/91804
6755/91804
7272/91804
7793/91804
8326/91804
8862/91804
9379/91804
9897/91804
10411/91804
10927/91804
11442/91804
11956/91804
12437/91804
447/91804
437/91804
978/91804
1525/91804
2040/91804
454/91804
1056/91804
1568/91804
2089/91804
2672/91804
3198/91804
3728/91804
4282/91804
4826/91804
5377/91804
5891/91804
6413/91804
6941/91804
7480/91804
8027/91804
8565/91804
9088/91804
9609/91804
9794/91804
507/91804
1019/91804
1531/91804
2043/91804
2239/91804
134/91804
548/91804
1292/91804
2316/91804
2584/91804
507/91804
837/91804
135/91804
486/91804
1001/91804
1514/91804
2027/91804
2545/91804
3057/91804
3571/91804
4086/91804
4599/91804
5113/91804
5627/91804
6144/91804
6655/91804
7166/91804
7679/91804
8196/91804
8710/91804
9229/91804
9745/91804
10259/91804
10773/91804
11288/91804
11802/91804
12321/91804
12834/91804
13348/91804
13864/91804
14378/91804
14893/91804
15407/91804
15918/91804
16431/91804
16944/91804
17458/91804
17971/91804
18484/91804
18997/91804
19508/91804
20021/91804
20535/91804
21047/91804
21560/91804
22072/91804
22584/91804
23096/91804
23609/91804
24122/91804
24638/91804
25149/91804
25664/91804
26176/91804
26689/91804
27203/91804
27715/91804
28227/91804
28739/91804
29251/91804
29764/91804
30277/91804
30789/91804
31301/91804
31813/91804
32325/91804
32838/91804
33306/91804
33819/91804
34333/91804
34846/91804
35357/91804
35869/91804
36381/91804
36894/91804
37407/91804
37922/91804
38435/91804
38948/91804
39460/91804
39972/91804
40488/91804
41002/91804
41514/91804
42028/91804
42540/91804
43052/91804
43566/91804
44079/91804
44594/91804
45105/91804
45619/91804
46132/91804
46644/91804
47156/91804
47668/91804
48180/91804
48692/91804
49204/91804
49716/91804
50228/91804
50741/91804
51252/91804
51765/91804
52277/91804
52790/91804
53305/91804
53821/91804
54335/91804
54852/91804
55365/91804
55881/91804
56396/91804
56442/91804
545/91804
1287/91804
2311/91804
2584/91804
507/91804
845/91804
4/91804
Unzip succeeded

有人可以帮助我吗？

Answer 1

这是因为你使用压缩的zipFile的长度作为最大值，并且从每个未压缩的zipEntry中读取的字节数作为位置 - 压缩文件的大小在大多数情况下与未压缩的不同，也可以有多个zip 包中的文件 - 因此在这种情况下，每个文件的进度将从 0 跳转到某个值(实际 zi​​pEntry 的大小而不是压缩的 zipFile 长度)。要获得 zip 文件中的实际位置，请使用以下方法从 FileInputStream 获取对 FileChannel 的引用:FileInputStream#getChannel();

然后在更新进度时:

 updateProgress(channel.position(), length);

这将根据 zipFile 中读取的实际位置(而不是未压缩内容的大小)更新进度条。

可能是这样的:

package com.franckyi.lan.installer;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import javafx.concurrent.Task;

public class UnZipTask extends Task<Void>{

    private File zipfile;
    private File folder;

    public UnZipTask(File zipfile, File folder){
        this.zipfile = zipfile;
        this.folder = folder;
    }

    @Override
    protected Void call() throws Exception {
        FileInputStream is = new FileInputStream(zipfile.getCanonicalFile());
        FileChannel channel = is.getChannel();
        ZipInputStream zis = new ZipInputStream(new BufferedInputStream(is));
        ZipEntry ze = null;
        try {
            while ((ze = zis.getNextEntry()) != null) {
                 File f = new File(folder.getCanonicalPath(), ze.getName());
                if (ze.isDirectory()) {
                    f.mkdirs();
                    continue;
                }
                f.getParentFile().mkdirs();
                OutputStream fos = new BufferedOutputStream(new FileOutputStream(f));
                try {
                    try {
                        final byte[] buf = new byte[1024];
                        int bytesRead;
                        long nread = 0L;
                        long length = zipfile.length();

                        while (-1 != (bytesRead = zis.read(buf))){
                            fos.write(buf, 0, bytesRead);
                            nread += bytesRead;
                            System.out.println(nread + "/" + length);
                            updateProgress(channel.position(), length);
                        }
                    } finally {
                        fos.close();
                    }
                } catch (final IOException ioe) {
                    f.delete();
                    throw ioe;
                }
            }
        } finally {
            zis.close();
        }
        return null;
    }

    @Override
    protected void succeeded(){
        System.out.println("Unzip succeeded");
    }

}