@Override
protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {
String username = (String)token.getPrincipal();
User user = userService.findByUsername(username);
if(user == null) {
throw new UnknownAccountException();//没找到帐号
}
//交给AuthenticatingRealm使用CredentialsMatcher进行密码匹配，如果觉得人家的不好可以自定义实现
SimpleAuthenticationInfo authenticationInfo = new SimpleAuthenticationInfo(
user.getUsername(), //用户名
user.getPassword(), //密码
ByteSource.Util.bytes(user.getCredentialsSalt()),//salt=username+salt
getName() //realm name
);
return authenticationInfo;
}