Springsecurity之AuthenticationEntryPoint

    org.springframework.security.web.AuthenticationEntryPoint在spring-security-web里面，分析的版本是5.0。

    List-1

package org.springframework.security.web;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.security.core.AuthenticationException;

public interface AuthenticationEntryPoint {
    void commence(HttpServletRequest var1, HttpServletResponse var2, AuthenticationException var3) throws IOException, ServletException;
}

    当用户请求了一个受保护的资源，可是用户没有经过认证，那么抛出异常，AuthenticationEntryPoint. Commence(..)就会被调用。这个对应的代码在ExceptionTranslationFilter中，以下List-2，当ExceptionTranslationFilter catch到异常后，就会间接调用AuthenticationEntryPoint。

    List-2

public class ExceptionTranslationFilter extends GenericFilterBean {
    private AuthenticationEntryPoint authenticationEntryPoint;
......

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)req;
        HttpServletResponse response = (HttpServletResponse)res;

        try {
            chain.doFilter(request, response);
            this.logger.debug("Chain processed normally");
        } catch (IOException var9) {
            throw var9;
        } catch (Exception var10) {
            ......

            this.handleSpringSecurityException(request, response, chain, (RuntimeException)ase);
        }

    }

    private void handleSpringSecurityException(HttpServletRequest request, HttpServletResponse response, FilterChain chain, RuntimeException exception) throws IOException, ServletException {
        ......
        this.sendStartAuthentication(request, response, chain, (AuthenticationException)exception);
        ......
    }

    protected void sendStartAuthentication(HttpServletRequest request, HttpServletResponse response, FilterChain chain, AuthenticationException reason) throws ServletException, IOException {
        SecurityContextHolder.getContext().setAuthentication((Authentication)null);
        this.requestCache.saveRequest(request, response);
        this.logger.debug("Calling Authentication entry point.");
        this.authenticationEntryPoint.commence(request, response, reason);
    }
......

    因此，咱们能够经过定义AuthenticationEntryPoint统一处理抛出的异常，以下List-3

    List-3

@Component
@AllArgsConstructor
public class CustomAuthExceptionEntryPoint implements AuthenticationEntryPoint {

	@Override
	public void commence(HttpServletRequest request, HttpServletResponse response,
						 AuthenticationException authException) throws IOException {
		response.setCharacterEncoding(CommonConstants.UTF8);
		response.setContentType(CommonConstants.CONTENT_TYPE);
		R<String> result = new R<>();
		result.setCode(HttpStatus.HTTP_UNAUTHORIZED);
		if (authException != null) {
			result.setMsg("error");
			result.setData(authException.getMessage());
		}
		response.setStatus(HttpStatus.HTTP_UNAUTHORIZED);
		PrintWriter printWriter = response.getWriter();
		printWriter.append(JSONObject.toString(result));
	}
}

Reference:

1. https://silentwu.iteye.com/blog/2214397
2. 源码