public static boolean isFileUpdate(String oldName, String newName) {
File oldFile = new File(oldName);
File newFile = new File(newName);
try {
FileInputStream oldInStream = new FileInputStream(oldFile);
FileInputStream newInStream = new FileInputStream(newFile);
int oldChar = 0;
int newChar = 0;
while (true) {
oldChar = oldInStream.read();
newChar = newInStream.read();
if (oldChar != -1 && newChar != -1) {
if (oldChar != newChar) {
return false;
}
} else {
break;
}
}
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
2、读取该文件，返回一个字符串，通过equals判断两文件是否一致。
import java.math.BigInteger;
import java.security.MessageDigest;
public static boolean isFileUpdate(String oldName, String newName) {
File oldFile = new File(oldName);
File newFile = new File(newName);
String oldFileMd5 = getFileMD5(oldFile);
String newFileMd5 = getFileMD5(newFile);
if (oldFileMd5 == null || newFileMd5 == null) {
return false;
}
return (!oldFileMd5.equals(newFileMd5));
}
private static String getFileMD5(File file) {
if (!file.isFile()) {
return null;
}
MessageDigest digest = null;
FileInputStream inStream = null;
byte buffer[] = new byte[1024];
int len;
try {
digest = MessageDigest.getInstance("MD5");
inStream = new FileInputStream(file);
while ((len = inStream.read(buffer, 0, 1024)) != -1) {
digest.update(buffer, 0, len);
}
inStream.close();
} catch (Exception e) {
e.printStackTrace();
return null;
}
BigInteger bigInt = new BigInteger(1, digest.digest());
return bigInt.toString(16);
}
3、使用jar包：commons-codec-1.4.jar的md5比较方法
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
public static boolean isFileUpdate(String oldName, String newName) {
File oldFile = new File(oldName);
File newFile = new File(newName);
String oldFileMd5 = null;
String newFileMd5 = null;
try {
oldFileMd5 = new String(Hex.encodeHex(DigestUtils.md5(new FileInputStream(oldFile))));
newFileMd5 = new String(Hex.encodeHex(DigestUtils.md5(new FileInputStream(newFile))));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (oldFileMd5 == null || newFileMd5 == null) {
return false;
}
return (!oldFileMd5.equals(newFileMd5));
}
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