用java代码实现MD5加密

public class MD5Util {
public static String md5(String passWord1) {
try {
MessageDigest md5 = MessageDigest.getInstance("MD5");
/*md5.update(passWord1.getBytes());//如果要用多种数据加密成一条数据,这时候就要用update
* md5.update(id);
md5.digest();*/
byte [] digest = md5.digest(passWord1.getBytes());//如果只有一种数据要被加密,那么直接用digest即可。
return toHex(digest);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
return null;
}

private static String toHex(byte[] buf){//将二进制数据转换成十六进制字符串返回
char[] codes = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
StringBuilder sb = new StringBuilder();
for(int i=0;i<codes.length;i++){
int hi = (codes[i]>>4)&0x0f;
int lo = buf[i]&0x0f;
sb.append(codes[hi]).append(codes[lo]);
}
return sb.toString();
}
}