从Zip文件中读取内容

Question

我试图创建一个简单的java程序，从zip文件中读取并提取文件内容。Zip文件包含3个文件（txt、pdf、docx）。我需要阅读所有这些文件的内容，为此我正在使用ApacheTika。

有人能帮我实现这个功能吗。到目前为止，我已经试过了，但没有成功

代码片段

public class SampleZipExtract {


    public static void main(String[] args) {

        List<String> tempString = new ArrayList<String>();
        StringBuffer sbf = new StringBuffer();

        File file = new File("C:\\Users\\xxx\\Desktop\\abc.zip");
        InputStream input;
        try {

          input = new FileInputStream(file);
          ZipInputStream zip = new ZipInputStream(input);
          ZipEntry entry = zip.getNextEntry();

          BodyContentHandler textHandler = new BodyContentHandler();
          Metadata metadata = new Metadata();

          Parser parser = new AutoDetectParser();

          while (entry!= null){

                if(entry.getName().endsWith(".txt") || 
                           entry.getName().endsWith(".pdf")||
                           entry.getName().endsWith(".docx")){
              System.out.println("entry=" + entry.getName() + " " + entry.getSize());
                     parser.parse(input, textHandler, metadata, new ParseContext());
                     tempString.add(textHandler.toString());
                }
           }
           zip.close();
           input.close();

           for (String text : tempString) {
           System.out.println("Apache Tika - Converted input string : " + text);
           sbf.append(text);
           System.out.println("Final text from all the three files " + sbf.toString());
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (TikaException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 1

由于而中的条件，循环可能永远不会中断：

while (entry != null) {
  // If entry never becomes null here, loop will never break.
}

这里的null检查不同，您可以尝试：

ZipEntry entry = null;
while ((entry = zip.getNextEntry()) != null) {
  // Rest of your code
}

Answer 2

从Java7开始，NIO Api提供了一种更好、更通用的方式来访问Zip或Jar文件的内容。实际上，它现在是一个统一的应用编程接口，允许您像对待普通文件一样对待Zip文件。

为了在此API中提取zip文件中包含的所有文件，您需要执行以下操作：

在Java8：

private void extractAll(URI fromZip, Path toDirectory) throws IOException{
    FileSystems.newFileSystem(fromZip, Collections.emptyMap())
            .getRootDirectories()
            .forEach(root -> {
                // in a full implementation, you'd have to
                // handle directories 
                Files.walk(root).forEach(path -> Files.copy(path, toDirectory));
            });
}

在java 7中：

private void extractAll(URI fromZip, Path toDirectory) throws IOException{
    FileSystem zipFs = FileSystems.newFileSystem(fromZip, Collections.emptyMap());

    for(Path root : zipFs.getRootDirectories()) {
        Files.walkFileTree(root, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) 
                    throws IOException {
                // You can do anything you want with the path here
                Files.copy(file, toDirectory);
                return FileVisitResult.CONTINUE;
            }

            @Override
            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) 
                    throws IOException {
                // In a full implementation, you'd need to create each 
                // sub-directory of the destination directory before 
                // copying files into it
                return super.preVisitDirectory(dir, attrs);
            }
        });
    }
}

Answer 3

如果你想知道如何从每个ZipEntry中获取文件内容，其实很简单。下面是一个示例代码：

public static void main(String[] args) throws IOException {
    ZipFile zipFile = new ZipFile("C:/test.zip");

    Enumeration<? extends ZipEntry> entries = zipFile.entries();

    while(entries.hasMoreElements()){
        ZipEntry entry = entries.nextElement();
        InputStream stream = zipFile.getInputStream(entry);
    }
}

一旦你有了输入流，你就可以随心所欲地阅读它。