Java java.util.zip.ZipFile.size()用法及代码示例

描述

这个java.util.zip.ZipFile.size()方法返回 ZIP 文件中的条目数。

声明

以下是声明java.util.zip.ZipFile.size()方法。

public int size()

返回

ZIP 文件中的条目数。

先决条件

在里面创建一个文件 Hello.txtD:> test > 包含以下内容的目录。

This is an example.

示例

下面的例子展示了 java.util.zip.ZipFile.size() 方法的用法。

package com.tutorialspoint;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.Enumeration;
import java.util.zip.Adler32;
import java.util.zip.CheckedOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;

public class ZipFileDemo {
   private static String SOURCE_FILE = "D:\\test\\Hello.txt";
   private static String TARGET_FILE = "D:\\test\\Hello.zip";

   public static void main(String[] args) {
      try {
         createZipFile();
         readZipFile();
      } catch(IOException ioe) {
         System.out.println("IOException:" + ioe);
      }
   }

   private static void createZipFile() throws IOException{
      FileOutputStream fout = new FileOutputStream(TARGET_FILE);
      CheckedOutputStream checksum = new CheckedOutputStream(fout, new Adler32());
      ZipOutputStream zout = new ZipOutputStream(checksum);

      FileInputStream fin = new FileInputStream(SOURCE_FILE);
      ZipEntry zipEntry = new ZipEntry(SOURCE_FILE);
      zipEntry.setComment("This is a sample file.");
      zout.putNextEntry(zipEntry);
      int length;
      byte[] buffer = new byte[1024];
      while((length = fin.read(buffer)) > 0) {
         zout.write(buffer, 0, length);
      }

      zout.closeEntry();
      fin.close();
      zout.close();
   }

   private static void readZipFile() throws IOException{
      final ZipFile file = new ZipFile(TARGET_FILE); 
      System.out.printf("Zip File:%s, Contains %d file(s). %n",file.getName(), file.size()); 
      try { 
         ZipEntry entry = file.getEntry(SOURCE_FILE);
         if(entry != null){
            System.out.printf("File:%s Size %d Modified on %TD %n", 
               entry.getName(), entry.getSize(), 
               new Date(entry.getTime()));
            extractFile(entry, file.getInputStream(entry)); 
         }
         System.out.printf("Zip file %s extracted successfully.", SOURCE_FILE); 
      } 
      finally { 
         file.close(); 
      }
   }

   private static void extractFile(final ZipEntry entry, InputStream is) 
      throws IOException {
      FileOutputStream fos = null; 
      try { 
         fos = new FileOutputStream(entry.getName()); 
         final byte[] buf = new byte[1024]; 
         int read = 0; 
         int length; 
         while ((length = is.read(buf, 0, buf.length)) >= 0) { 
            fos.write(buf, 0, length); 
         } 
      } catch (IOException ioex) { 
         fos.close(); 
      } 
   }
}

让我们编译并运行上面的程序，这将产生以下结果——

Zip File:D:\test\Hello.zip, Contains 1 file(s). 
File:D:\test\Hello.txt Size 1024 Modified on 05/22/17 
Zip file D:\test\Hello.txt extracted successfully.