Java操作Zip文件-如何打开rar文件

Java对ZIP文件格式有直接支持。通常，我们将使用java.util.zip包中的以下四个类来处理ZIP文件格式：

ZipEntry
ZipInputStream
ZipOutputStream
ZipFile

ZipEntry对象表示ZIP文件格式的归档文件中的条目。

zip条目可以是压缩的或未压缩的。

ZipEntry类具有设置和获取有关ZIP文件中的条目的信息的方法。

ZipInputStream可以从每个条目的ZIP文件读取数据。

ZipOutputStream可以将数据写入每个条目的ZIP文件。

ZipFile是一个从ZIP文件读取条目的实用程序类。

以下代码显示如何创建ZIP文件

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.Deflater;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class Main {
 public static void main(String[] args) {
 String zipFileName = "ziptest.zip";
 String[] entries = new String[2];
 entries[0] = "test1.txt";
 entries[1] = "notes" + File.separator + "test2.txt";
 zip(zipFileName, entries);
 }
 public static void zip(String zipFileName, String[] zipEntries) {
 try (ZipOutputStream zos = new ZipOutputStream(new BufferedOutputStream(
 new FileOutputStream(zipFileName)))) {
 // Set the compression level to best compression
 zos.setLevel(Deflater.BEST_COMPRESSION);
 for (int i = 0; i < zipEntries.length; i++) {
 File entryFile = new File(zipEntries[i]);
 if (!entryFile.exists()) {
 System.out.println("The entry file " + entryFile.getAbsolutePath()
 + " does not exist");
 System.out.println("Aborted processing.");
 return;
 }
 ZipEntry ze = new ZipEntry(zipEntries[i]);
 zos.putNextEntry(ze);
 addEntryContent(zos, zipEntries[i]);
 zos.closeEntry();
 }
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 public static void addEntryContent(ZipOutputStream zos, String entryFileName)
 throws IOException, FileNotFoundException {
 BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
 entryFileName));
 byte[] buffer = new byte[1024];
 int count = -1;
 while ((count = bis.read(buffer)) != -1) {
 zos.write(buffer, 0, count);
 }
 bis.close();
 }
}

读取Zip文件

以下代码显示如何读取ZIP文件的内容。

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class Main {
 public static void main(String[] args) {
 String zipFileName = "ziptest.zip";
 String unzipdirectory = "extracted";
 unzip(zipFileName, unzipdirectory);
 }
 public static void unzip(String zipFileName, String unzipdir) {
 try (ZipInputStream zis = new ZipInputStream(new BufferedInputStream(
 new FileInputStream(zipFileName)))) {
 ZipEntry entry = null;
 while ((entry = zis.getNextEntry()) != null) {
 // Extract teh entry"s contents 
 extractEntryContent(zis, entry, unzipdir);
 }
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 public static void extractEntryContent(ZipInputStream zis, ZipEntry entry,
 String unzipdir) throws IOException, FileNotFoundException {
 String entryFileName = entry.getName();
 String entryPath = unzipdir + File.separator + entryFileName;
 createFile(entryPath);
 BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(
 entryPath));
 byte[] buffer = new byte[1024];
 int count = -1;
 while ((count = zis.read(buffer)) != -1) {
 bos.write(buffer, 0, count);
 }
 bos.close();
 }
 public static void createFile(String filePath) throws IOException {
 File file = new File(filePath);
 File parent = file.getParentFile();
 if (!parent.exists()) {
 parent.mkdirs();
 }
 file.createNewFile();
 }
}

例2

下面的代码显示了如何使用ZipFile类。

当你只想在ZIP文件中列出条目时，ZipFile类派上用场。

import java.io.InputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class Main {
 public static void main(String[] args) throws Exception {
 ZipFile zf = new ZipFile("ziptest.zip");
 // Get the enumeration for all zip entries and loop through them
 Enumeration<? extends ZipEntry> e = zf.entries();
 ZipEntry entry = null;
 while (e.hasMoreElements()) {
 entry = e.nextElement();
 // Get the input stream for the current zip entry
 InputStream is = zf.getInputStream(entry);
 /* Read data for the entry using the is object */
 // Print the name of the entry
 System.out.println(entry.getName());
 }
 }
}

以下代码使用Stream类和lambda表达式重写上述代码。

import java.io.IOException;
import java.io.InputStream;
import java.util.stream.Stream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
public class Main {
 public static void main(String[] args) throws Exception {
 ZipFile zf = new ZipFile("ziptest.zip");
 Stream<? extends ZipEntry> entryStream = zf.stream();
 entryStream.forEach(entry -> {
 try {
 // Get the input stream for the current zip entry
 InputStream is = zf.getInputStream(entry);
 System.out.println(entry.getName());
 } catch (IOException e) {
 e.printStackTrace();
 }
 });
 }
}