高质量编写非功能性代码的一些实践

 /** * Gets a property from the configuration. * * @param key property to retrieve * @return value as object. Will return user value if exists, * if not then default value if exists, otherwise null */ public Object getProperty(String key) { // first, try to get from the 'user value' store Object obj = this.get(key);
 if (obj == null) { // if there isn't a value there, get it from the // defaults if we have them if (defaults != null) { obj = defaults.get(key); } }
 return obj; }
// org.apache.commons.collections.ExtendedProperties

public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) { RelaxedPropertyResolver resolver = new RelaxedPropertyResolver( event.getEnvironment(), "spring."); if (resolver.containsProperty("mandatoryFileEncoding")) { String encoding = System.getProperty("file.encoding"); String desired = resolver.getProperty("mandatoryFileEncoding"); if (encoding != null && !desired.equalsIgnoreCase(encoding)) { logger.error("System property 'file.encoding' is currently '" + encoding + "'. It should be '" + desired + "' (as defined in 'spring.mandatoryFileEncoding')."); logger.error("Environment variable LANG is '" + System.getenv("LANG") + "'. You could use a locale setting that matches encoding='" + desired + "'."); logger.error("Environment variable LC_ALL is '" + System.getenv("LC_ALL") + "'. You could use a locale setting that matches encoding='" + desired + "'."); throw new IllegalStateException( "The Java Virtual Machine has not been configured to use the " + "desired default character encoding (" + desired + ")."); } } }
// org.springframework.boot.context.FileEncodingApplicationListener

 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);
 logger.debug("Chain processed normally"); } catch (IOException ex) { throw ex; } catch (Exception ex) { // Try to extract a SpringSecurityException from the stacktrace Throwable[] causeChain = throwableAnalyzer.determineCauseChain(ex); RuntimeException ase = (AuthenticationException) throwableAnalyzer .getFirstThrowableOfType(AuthenticationException.class, causeChain);
 if (ase == null) { ase = (AccessDeniedException) throwableAnalyzer.getFirstThrowableOfType( AccessDeniedException.class, causeChain); }
 if (ase != null) { handleSpringSecurityException(request, response, chain, ase); } else { // Rethrow ServletExceptions and RuntimeExceptions as-is if (ex instanceof ServletException) { throw (ServletException) ex; } else if (ex instanceof RuntimeException) { throw (RuntimeException) ex; }
 // Wrap other Exceptions. This shouldn't actually happen // as we've already covered all the possibilities for doFilter throw new RuntimeException(ex); } } }
 private void handleSpringSecurityException(HttpServletRequest request, HttpServletResponse response, FilterChain chain, RuntimeException exception) throws IOException, ServletException { if (exception instanceof AuthenticationException) { logger.debug( "Authentication exception occurred; redirecting to authentication entry point", exception);
 sendStartAuthentication(request, response, chain, (AuthenticationException) exception); } else if (exception instanceof AccessDeniedException) { Authentication authentication = SecurityContextHolder.getContext().getAuthentication(); if (authenticationTrustResolver.isAnonymous(authentication) || authenticationTrustResolver.isRememberMe(authentication)) { logger.debug( "Access is denied (user is " + (authenticationTrustResolver.isAnonymous(authentication) ? "anonymous" : "not fully authenticated") + "); redirecting to authentication entry point", exception);
 sendStartAuthentication( request, response, chain, new InsufficientAuthenticationException( "Full authentication is required to access this resource")); } else { logger.debug( "Access is denied (user is not anonymous); delegating to AccessDeniedHandler", exception);
 accessDeniedHandler.handle(request, response, (AccessDeniedException) exception); } } }
 protected void sendStartAuthentication(HttpServletRequest request, HttpServletResponse response, FilterChain chain, AuthenticationException reason) throws ServletException, IOException { // SEC-112: Clear the SecurityContextHolder's Authentication, as the // existing Authentication is no longer considered valid SecurityContextHolder.getContext().setAuthentication(null); requestCache.saveRequest(request, response); logger.debug("Calling Authentication entry point."); authenticationEntryPoint.commence(request, response, reason); }
// org.springframework.security.web.access.ExceptionTranslationFilter