Question

我在使用Java解压缩ZIP文件时遇到问题。方法如下。

文件解压缩后文件结构正确，这意味着ZIP文件中的目录很好，但文件输出的长度为零。

我已经检查了ZIP文件，看看压缩是否正确，一切都正确。

如果有人看到我错过的东西......

public static void unzip ( File zipfile, File directory ) throws IOException {
  ZipFile zip = new ZipFile ( zipfile );
  Enumeration<? extends ZipEntry> entries = zip.entries ();

  while ( entries.hasMoreElements () ) {
    ZipEntry entry = entries.nextElement ();
    File file = new File ( directory, entry.getName () );

    if ( entry.isDirectory () ) {
      file.mkdirs ();
    }
    else {
      file.getParentFile ().mkdirs ();

      ZipInputStream in = new ZipInputStream ( zip.getInputStream ( entry ) );
      OutputStream out = new FileOutputStream ( file );
      byte[] buffer = new byte[4096];
      int readed = 0;

      while ( ( readed = in.read ( buffer ) ) > 0 ) {
        out.write ( buffer, 0, readed );
        out.flush ();
      }

      out.close ();
      in.close ();
    }
  }

  zip.close ();
}

更多......显然方法 getInputStream（entry）返回零字节，不知道为什么。

Answer 1

ZipFile已经解压缩条目的数据，也不需要使用ZipInputStream。

而不是：

ZipInputStream in = new ZipInputStream ( zip.getInputStream ( entry ) );

使用：

InputStream in = zip.getInputStream ( entry );

ZipInputStream也可用于解压缩ZIP文件。你得到零长度流的原因是因为使用ZipInputStream你需要调用getNextEntry（）来读取ZIP中的第一个文件。

Answer 2

以下代码有效：

package so;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipInputStream;

public class TestZip {

    public static void main(String[] args) {
        String path = "C:" + File.separator + "tmp" + File.separator;
        String nom = "demo.zip";
        File zipfile = new File(path + nom);
        File directory = new File(path);
        TestZip m = new TestZip();
        try {
            m.unzip(zipfile, directory);
        } catch (Exception e) {
            e.printStackTrace(System.out);
        }
    }

    public static void unzip ( File zipfile, File directory ) throws IOException {
        System.out.println(zipfile.toString());
        System.out.println(directory.toString());
          ZipFile zip = new ZipFile (  zipfile );
          System.out.println("1");
          Enumeration<? extends ZipEntry> entries = zip.entries ();
          System.out.println("2");

          while ( entries.hasMoreElements () ) {
              System.out.println("3");
            ZipEntry entry = entries.nextElement ();
            File file = new File ( directory, entry.getName () );

            if ( entry.isDirectory () ) {
              file.mkdirs ();
            }
            else {
              file.getParentFile ().mkdirs ();

              ZipInputStream in = new ZipInputStream ( zip.getInputStream ( entry ) );
              OutputStream out = new FileOutputStream ( file );
              byte[] buffer = new byte[4096];
              int readed = 0;

              while ( ( readed = in.read ( buffer ) ) > 0 ) {
                out.write ( buffer, 0, readed );
                out.flush ();
              }

              out.close ();
              in.close ();
            }
          }

          zip.close ();
        }


}

所以我认为问题在于您传递的参数。使用“new File（complete_path + filename）”创建参数“zipfile”。如果您只是使用文件名创建它不起作用。

使用Java ZipFile类解压缩ZIP文件

2 个答案: