对于客户端开发或者网站开发而言，调用接口返回有统一的响应体，可以针对性的设计界面，代码结构更加清晰，层次也更加分明。

默认异常响应

在使用 Spring Security Oauth2 登录和鉴权失败时，默认返回的异常信息如下：

{
  "error": "unauthorized",
  "error_description": "Full authentication is required to access this resource"
}

这与我们返回的信息格式不一致。如果需要修改这种返回的格式，需要重写相关异常处理类。这里我统一的是资源服务器（网关）的响应格式。

自定义异常响应

无效 token 异常类重写

新增 AuthExceptionEntryPoint.java

@Component
public class AuthExceptionEntryPoint implements AuthenticationEntryPoint
{

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response,
                         AuthenticationException authException) throws ServletException {
        Map map = new HashMap();
        Throwable cause = authException.getCause();

        response.setStatus(HttpStatus.OK.value());
        response.setHeader("Content-Type", "application/json;charset=UTF-8");
        try {
            if(cause instanceof InvalidTokenException) {
                response.getWriter().write(ResultJsonUtil.build(
                        ResponseCodeConstant.REQUEST_FAILED,
                        ResponseStatusCodeConstant.OAUTH_TOKEN_FAILURE,
                        ResponseMessageConstant.OAUTH_TOKEN_ILLEGAL
                ));
            }else{
                response.getWriter().write(ResultJsonUtil.build(
                        ResponseCodeConstant.REQUEST_FAILED,
                        ResponseStatusCodeConstant.OAUTH_TOKEN_MISSING,
                        ResponseMessageConstant.OAUTH_TOKEN_MISSING
                ));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

权限不足异常类重写

新增 CustomAccessDeniedHandler.java

@Component("customAccessDeniedHandler")
public class CustomAccessDeniedHandler implements AccessDeniedHandler {

    @Override
    public void handle(HttpServletRequest request, HttpServletResponse response,
                       AccessDeniedException accessDeniedException)
            throws IOException, ServletException {
        response.setStatus(HttpStatus.OK.value());
        response.setHeader("Content-Type", "application/json;charset=UTF-8");
        try {
            response.getWriter().write(ResultJsonUtil.build(
                    ResponseCodeConstant.REQUEST_FAILED,
                    ResponseStatusCodeConstant.OAUTH_TOKEN_DENIED,
                    ResponseMessageConstant.OAUTH_TOKEN_DENIED
            ));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

资源配置类中设置异常处理类

修改资源配置类 ResourceServerConfiguration.java

@Override
public void configure(ResourceServerSecurityConfigurer resources) {
    resources.tokenExtractor(customTokenExtractor);
    resources.authenticationEntryPoint(authExceptionEntryPoint)
            .accessDeniedHandler(customAccessDeniedHandler);
}

自定义响应测试

示例代码：https://github.com/BNDong/spring-cloud-examples/tree/master/spring-cloud-zuul/cloud-zuul