acegi的登陆过程

先来无事看看acegi的登陆过滤器 写下来当作备忘吧
主要的类是AuthenticationProcessingFilter 继承了AbstractProcessingFilter 这要的逻辑都在后面这个类中
让我们看看核心代码吧

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException,
			ServletException {
		if (!(request instanceof HttpServletRequest)) {
			throw new ServletException("Can only process HttpServletRequest");
		}

		if (!(response instanceof HttpServletResponse)) {
			throw new ServletException("Can only process HttpServletResponse");
		}

		HttpServletRequest httpRequest = (HttpServletRequest) request;
		HttpServletResponse httpResponse = (HttpServletResponse) response;

		if (requiresAuthentication(httpRequest, httpResponse)) {
			if (logger.isDebugEnabled()) {
				logger.debug("Request is to process authentication");
			}

			Authentication authResult;
//下面才是重点 上面都是些基本检查
			try {
				onPreAuthentication(httpRequest, httpResponse);
				authResult = attemptAuthentication(httpRequest);//这个方法就是去登陆了 就是调用dao检查用户名密码 登陆不成功将抛出异常
			}
			catch (AuthenticationException failed) {
				// Authentication failed
				unsuccessfulAuthentication(httpRequest, httpResponse, failed);

				return;
			}

			// Authentication success
			if (continueChainBeforeSuccessfulAuthentication) {
				chain.doFilter(request, response);
			}

			successfulAuthentication(httpRequest, httpResponse, authResult);

			return;
		}

		chain.doFilter(request, response);
	}

看一些登陆成功后 做些什么

	protected void successfulAuthentication(HttpServletRequest request, HttpServletResponse response,
			Authentication authResult) throws IOException {
		if (logger.isDebugEnabled()) {
			logger.debug("Authentication success: " + authResult.toString());
		}

//把用户信息保存到SecurityContextHolder中1980
SecurityContextHolder.getContext().setAuthentication(authResult);

		if (logger.isDebugEnabled()) {
			logger.debug("Updated SecurityContextHolder to contain the following Authentication: '" + authResult + "'");
		}
//转到目标页面 即登陆成功页面
		String targetUrl = determineTargetUrl(request);

		if (logger.isDebugEnabled()) {
			logger.debug("Redirecting to target URL from HTTP Session (or default): " + targetUrl);
		}

		onSuccessfulAuthentication(request, response, authResult);

		rememberMeServices.loginSuccess(request, response, authResult);

		// Fire event
		if (this.eventPublisher != null) {
			eventPublisher.publishEvent(new InteractiveAuthenticationSuccessEvent(authResult, this.getClass()));
		}

		sendRedirect(request, response, targetUrl);
	}