import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.CRC32;
import java.util.zip.CheckedInputStream;
import org.junit.Test;
public class CRCTest {
@Test
public void testFileCRC() {
try {
System.out.println(getCRC32("C:\\software.xml"));
System.out.println(checksumBufferedInputStream("C:\\software.xml"));
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 采用BufferedInputStream的方式加载文件
*/
public static long checksumBufferedInputStream(String filepath) throws IOException {
InputStream inputStream = new BufferedInputStream(new FileInputStream(filepath));
CRC32 crc = new CRC32();
byte[] bytes = new byte[1024];
int cnt;
while ((cnt = inputStream.read(bytes)) != -1) {
crc.update(bytes, 0, cnt);
}
inputStream.close();
return crc.getValue();
}
/**
* 使用CheckedInputStream计算CRC
*/
public static Long getCRC32(String filepath) throws IOException {
CRC32 crc32 = new CRC32();
FileInputStream fileinputstream = new FileInputStream(new File(filepath));
CheckedInputStream checkedinputstream = new CheckedInputStream(fileinputstream, crc32);
while (checkedinputstream.read() != -1) {
}
checkedinputstream.close();
return crc32.getValue();
}
}
原文地址:https://www.cnblogs.com/liaojie970/p/4872132.html