抽时间写了一个算法工具类，目前支持的算法有SHA1,SHA256,SHA384,SHA512,MD5,同时支持获取文件的MD5值。
使用方法如下：
获取字符串的MD5值
String str= AlgorithmHelper.getHash("123", AlgorithmHelper.MD5)
获取字符串的SHA256值
String str= AlgorithmHelper.getHash("123", AlgorithmHelper.SHA256);
获取文件的MD5值
File file=new File(Environment.getExternalStorageDirectory().getAbsolutePath()+File.separator+"1.jpg");
String str=AlgorithmHelper.getMD5(file);
代码文件如下：
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map; public class AlgorithmHelper { private final static Map<Integer, String> mapList = new HashMap<Integer, String>();
private final static char[] HEX_CHARS = "0123456789ABCDEF".toCharArray(); public final static int SHA1 = 0;
public final static int SHA256 = 1;
public final static int SHA384 = 2;
public final static int SHA512 = 3;
public final static int MD5 = 4; static {
mapList.put(SHA1, "SHA-1");
mapList.put(SHA256, "SHA-256");
mapList.put(SHA384, "SHA-384");
mapList.put(SHA512, "SHA-512");
mapList.put(MD5, "MD5");
} private static String convertToHex(byte[] bytes) {
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = HEX_CHARS[v >>> 4];
hexChars[j * 2 + 1] = HEX_CHARS[v & 0x0F];
}
return new String(hexChars);
} public static String getHash(String text, int algorithm) {
String hash = null;
try {
if (mapList.containsKey(algorithm)) {
final MessageDigest digest = MessageDigest.getInstance(mapList.get(algorithm));
final byte[] bytes = text.getBytes("UTF-8");
digest.update(bytes, 0, bytes.length);
hash = convertToHex(digest.digest());
}
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return hash;
} //获取字符串的MD5值
public static String getMD5(String text) {
return getHash(text, MD5);
} //获取文件的MD5值
public static String getMD5(File file) {
String hash = null;
if (file == null || !file.exists()) {
return hash;
} InputStream is = null;
try {
MessageDigest messageDigest = MessageDigest.getInstance("MD5");
is = new FileInputStream(file);
byte[] buffer = new byte[1024];
int len = -1;
while ((len = is.read(buffer)) != -1) {
messageDigest.update(buffer, 0, len);
}
byte[] bytes = messageDigest.digest();
hash = convertToHex(bytes);
} catch (Exception e) {
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return hash;
}
}