java.util.zip.CRC32.getValue()方法範例

java.util.zip.CRC32.getValue()方法返回校驗和值。

宣告

以下是java.util.zip.CRC32.getValue方法的宣告。

public long getValue()

返回值

當前的校驗和值。

在D:\test>目錄下用以下內容建立一個檔案Hello.txt。

This is an example.

範例

以下範例顯示了java.util.zip.CRC32.getValue()方法的用法。

package com.yiibai;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.CRC32;
import java.util.zip.CheckedOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class CRC32Demo {

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

   public static void main(String[] args) {
      byte[] buffer = new byte[1024];

      try {
         FileOutputStream fout = new FileOutputStream(TARGET_FILE);
         CheckedOutputStream checksum = new CheckedOutputStream(fout, new CRC32());
         ZipOutputStream zout = new ZipOutputStream(checksum);

         FileInputStream fin = new FileInputStream(SOURCE_FILE);
         zout.putNextEntry(new ZipEntry(SOURCE_FILE));
         int length;
         while((length = fin.read(buffer)) > 0) {
            zout.write(buffer, 0, length);
         }

         zout.closeEntry();
         fin.close();
         zout.close();
         System.out.println("Zip file generated!");
         System.out.println("CRC32 Checksum is : " + checksum.getChecksum().getValue());
      } catch(IOException ioe) {
         System.out.println("IOException : " + ioe);
      }
   }
}

執行上面範例程式碼，得到以下結果 -

Zip file generated!
CRC32 Checksum is : 3847524486