spring security oauth2实现多端登录互不影响

在项目中使用spring security oauth2做了统一登录授权，在实际开发过程中，发现不同终端同一账号登录，返回的token是一样的。我们使用的是redis存储token，于是查了资料，发现是因为生成token key的算法的原因，导致了多端登录返回一个token的问题，原因如图：

调用代码：

生成key使用的是DefaultAuthenticationKeyGenerator，代码：

public class DefaultAuthenticationKeyGenerator implements AuthenticationKeyGenerator {

    private static final String CLIENT_ID = "client_id";

    private static final String SCOPE = "scope";

    private static final String USERNAME = "username";

    public String extractKey(OAuth2Authentication authentication) {
        Map<String, String> values = new LinkedHashMap<String, String>();
        OAuth2Request authorizationRequest = authentication.getOAuth2Request();
        if (!authentication.isClientOnly()) {
            values.put(USERNAME, authentication.getName());
        }
        values.put(CLIENT_ID, authorizationRequest.getClientId());
        if (authorizationRequest.getScope() != null) {
            values.put(SCOPE, OAuth2Utils.formatParameterList(new TreeSet<String>(authorizationRequest.getScope())));
        }
        return generateKey(values);
    }

    protected String generateKey(Map<String, String> values) {
        MessageDigest digest;
        try {
            digest = MessageDigest.getInstance("MD5");
            byte[] bytes = digest.digest(values.toString().getBytes("UTF-8"));
            return String.format("%032x", new BigInteger(1, bytes));
        } catch (NoSuchAlgorithmException nsae) {
            throw new IllegalStateException("MD5 algorithm not available.  Fatal (should be in the JDK).", nsae);
        } catch (UnsupportedEncodingException uee) {
            throw new IllegalStateException("UTF-8 encoding not available.  Fatal (should be in the JDK).", uee);
        }
    }
}

从代码里面看，生成key使用的是 client_id、scope、username三个字段，由于这三个字段同一用户在同一子系统中是不变的，所以导致多端登录时，生成的token key是一样的，就会造成返回的token一样，这样的后果就是，其中一个终端退出登录，所有已登录设备就失效了，于是就重写这extractKey方法，继承这个类，增加了一个device_id字段，从而解决多端登录需要互不干扰的需求：

public class CustomAuthenticationKeyGenerator extends DefaultAuthenticationKeyGenerator {
    private static final String CLIENT_ID = "client_id";

    private static final String SCOPE = "scope";

    private static final String USERNAME = "username";

    private static final String DEVICE_ID = "device_id";

    @Override
    public String extractKey(OAuth2Authentication authentication) {
        Map<String, String> values = new LinkedHashMap<String, String>();
        OAuth2Request authorizationRequest = authentication.getOAuth2Request();
        if (!authentication.isClientOnly()) {
            values.put(USERNAME, authentication.getName());
        }
        values.put(CLIENT_ID, authorizationRequest.getClientId());
        if (authorizationRequest.getScope() != null) {
            values.put(SCOPE, OAuth2Utils.formatParameterList(new TreeSet<String>(authorizationRequest.getScope())));
        }

        String deviceId = authorizationRequest.getRequestParameters().get(DEVICE_ID);
        values.put(DEVICE_ID, deviceId);

        return generateKey(values);
    }
}