Spring-从过滤器返回JSON格式的错误消息

Question

我正在使用Spring Boot REST应用程序。

我注册了一个自定义AuthenticationEntryPoint，如果用户不提供凭据，则返回401 Unauthorized错误。

@Component
public class CustomAuthenticationEntryPoint implements AuthenticationEntryPoint {

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException {
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized");
    }
}

这很好用，并返回如下所示的JSON格式的DefaultErrorAttributes：

{
  "timestamp": 1465230610451,
  "status": 401,
  "error": "Unauthorized",
  "exception": "org.springframework.security.authentication.BadCredentialsException",
  "message": "Unauthorized",
  "path": "/webapp/login"
}

现在，我已使用以下Filter覆盖将doFilter()添加到应用程序：

@ Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)throws IOException, ServletException {
    try {
        // Here be some code that fails.
    } catch (Exception e) {
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized");
    }

    chain.doFilter(request, response);
}

但是，此代码返回默认的Tomcat“错误报告” HTML页面，而不是上面显示的JSON格式的DefaultErrorAttributes。

为什么会发生这种情况？在两种情况下使两种错误消息保持一致（JSON格式）的最佳方法是什么？

Answer 1

原始链接http://teknosrc.com/java-break-filter-chain-return-custom-pojo-response-servlet/

public class TestFilter implements Filter {

@Override
public void init(FilterConfig filterConfig) throws ServletException {

}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,ServletException {

    if(ANY CONDITION){
        //ANY POJO CLASS
        // ErrorResponse is a public return object that you define yourself
        ErrorResponse errorResponse = new ErrorResponse();
        errorResponse.setCode(401);
        errorResponse.setMessage("Unauthorized Access");

        byte[] responseToSend = restResponseBytes(errorResponse);
        ((HttpServletResponse) response).setHeader("Content-Type", "application/json");
        ((HttpServletResponse) response).setStatus(401);
        response.getOutputStream().write(responseToSend);
        return;
    }

    //ANY OTHER BUSINESS LOGIC
    chain.doFilter(request, response);
}

@Override
public void destroy() {

}

private byte[] restResponseBytes(ErrorResponse eErrorResponse) throws IOException {
    String serialized = new ObjectMapper().writeValueAsString(eErrorResponse);
    return serialized.getBytes();
}  }