import java.io.FileInputStream;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class Md5Utils {
//十六进制
private static final char HEX_DIGITS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
/**
* byte数组转换为转换为16进制
* @param b 数据
* @return 返回字符串
*/
private static String toHexString(byte[] b) {
StringBuilder sb = new StringBuilder(b.length * 2);
for (int i = 0; i < b.length; i++) {
sb.append(HEX_DIGITS[(b[i] & 0xf0) >>> 4]);
sb.append(HEX_DIGITS[b[i] & 0x0f]);
}
return sb.toString();
}
/**
* MD5对字符串校验
* @param string
* @return
*/
public static String md5(String string) {
byte[] bytes;
try {
bytes = MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8"));
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("MD5 should be supported?", e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("UTF-8 should be supported?", e);
}
return toHexString(bytes);
}
/**
* 取文件MD5值
* @param filename 文件路径
* @return MD5值
*/
public static String fileMD5(String filename) {
InputStream fis;
byte[] buffer = new byte[1024];
int numRead = 0;
MessageDigest md5;
try {
fis = new FileInputStream(filename);
md5 = MessageDigest.getInstance("MD5");
while ((numRead = fis.read(buffer)) > 0) {
md5.update(buffer, 0, numRead);
}
fis.close();
return toHexString(md5.digest());
} catch (Exception e) {
System.out.println("error");
return null;
}
}
}
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