java 拦截、过滤器2 - IT评测·应用市场-qidao123.com技术社区

@ControllerAdvice
public class GlobalHandler {
@ExceptionHandler(MethodArgumentNotValidException.class)
public Result exceptionHandler(MethodArgumentNotValidException e) {
Result result = new Result(BizExceptionEnum.INVALID_REQ_PARAM.getErrorCode(),
BizExceptionEnum.INVALID_REQ_PARAM.getErrorMsg());
logger.error("req params error", e);
return result;
}
}
// 上述对MethodArgumentNotValidException异常统一拦截后并统一返回异常

复制代码

public class DispatcherServlet extends FrameworkServlet {
// ......
protected void initStrategies(ApplicationContext context) {
initMultipartResolver(context);
initLocaleResolver(context);
initThemeResolver(context);
initHandlerMappings(context);
initHandlerAdapters(context);
// 处理所有异常
initHandlerExceptionResolvers(context);
initRequestToViewNameTranslator(context);
initViewResolvers(context);
initFlashMapManager(context);
}
// ......
}

复制代码

public class ExceptionHandlerExceptionResolver extends AbstractHandlerMethodExceptionResolver
implements ApplicationContextAware, InitializingBean {
// ......
private void initExceptionHandlerAdviceCache() {
// ......
List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(getApplicationContext());
AnnotationAwareOrderComparator.sort(adviceBeans);
for (ControllerAdviceBean adviceBean : adviceBeans) {
ExceptionHandlerMethodResolver resolver = new ExceptionHandlerMethodResolver(adviceBean.getBeanType());
if (resolver.hasExceptionMappings()) {
// 找到所有ExceptionHandler标注的方法并保存成一个ExceptionHandlerMethodResolver类型的对象缓存起来
this.exceptionHandlerAdviceCache.put(adviceBean, resolver);
if (logger.isInfoEnabled()) {
logger.info("Detected @ExceptionHandler methods in " + adviceBean);
}
}
// ......
}
}
}
public ExceptionHandlerMethodResolver(Class<?> handlerType) {
// 查询当前类中@ExceptionHandler的方法
for (Method method : MethodIntrospector.selectMethods(handlerType, EXCEPTION_HANDLER_METHODS)) {
// 获取方法的异常类型
for (Class<? extends Throwable> exceptionType : detectExceptionMappings(method)) {
// 添加到缓存中
addExceptionMapping(exceptionType, method);
}
}
}

复制代码

// 处理返回结果时，如果异常不为空，则进行异常处理
private void processDispatchResult(HttpServletRequest request, HttpServletResponse response,
@Nullable HandlerExecutionChain mappedHandler, @Nullable ModelAndView mv,
@Nullable Exception exception) throws Exception {
boolean errorView = false;
if (exception != null) {
if (exception instanceof ModelAndViewDefiningException) {
// ...
}
else {
Object handler = (mappedHandler != null ? mappedHandler.getHandler() : null);
// 调用异常Handler处理
mv = processHandlerException(request, response, handler, exception);
errorView = (mv != null);
}
}
// ...
}

复制代码

class RequestResponseBodyAdviceChain implements RequestBodyAdvice, ResponseBodyAdvice<Object> {
//它持有所有的，记住是所有的advice们
private final List<Object> requestBodyAdvice = new ArrayList<>(4);
private final List<Object> responseBodyAdvice = new ArrayList<>(4);
// 可以看到这是个通用的方法。内来进行区分存储的 getAdviceByType这个区分方法可以看一下
// 兼容到了ControllerAdviceBean以及beanType本身
public RequestResponseBodyAdviceChain(@Nullable List<Object> requestResponseBodyAdvice) {
this.requestBodyAdvice.addAll(getAdviceByType(requestResponseBodyAdvice, RequestBodyAdvice.class));
this.responseBodyAdvice.addAll(getAdviceByType(requestResponseBodyAdvice, ResponseBodyAdvice.class));
}
@Override
public boolean supports(MethodParameter param, Type type, Class<? extends HttpMessageConverter<?>> converterType) {
throw new UnsupportedOperationException("Not implemented");
}
@Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
throw new UnsupportedOperationException("Not implemented");
}
// 可以看到最终都是委托给具体的Advice去执行的（supports方法）
// 特点：符合条件的所有的`Advice`都会顺序的、依次的执行
@Override
public HttpInputMessage beforeBodyRead(HttpInputMessage request, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) throws IOException {
for (RequestBodyAdvice advice : getMatchingAdvice(parameter, RequestBodyAdvice.class)) {
if (advice.supports(parameter, targetType, converterType)) {
request = advice.beforeBodyRead(request, parameter, targetType, converterType);
}
}
return request;
}
... // 其余方法略。处理逻辑同上顺序执行。
// 最重要的是如下这个getMatchingAdvice()匹配方法
private <A> List<A> getMatchingAdvice(MethodParameter parameter, Class<? extends A> adviceType) {
// 简单的说你想要的是Request的还是Response的List呢？
List<Object> availableAdvice = getAdvice(adviceType);
if (CollectionUtils.isEmpty(availableAdvice)) {
return Collections.emptyList();
}
List<A> result = new ArrayList<>(availableAdvice.size());
for (Object advice : availableAdvice) {
if (advice instanceof ControllerAdviceBean) {
ControllerAdviceBean adviceBean = (ControllerAdviceBean) advice;
// 这里面会调用beanTypePredicate.test(beanType)方法
// 也就是根据basePackages等等判断此advice是否是否要作用在本类上
if (!adviceBean.isApplicableToBeanType(parameter.getContainingClass())) {
continue;
}
advice = adviceBean.resolveBean();
}
// 当前的advice若是满足类型要求的，那就添加进去最终执行切面操作
if (adviceType.isAssignableFrom(advice.getClass())) {
result.add((A) advice);
}
}
return result;
}
}

复制代码

AbstractMessageConverterMethodArgumentResolver（一般实际为RequestResponseBodyMethodProcessor）：
// 唯一构造函数，指定所有的advices
public AbstractMessageConverterMethodArgumentResolver(List<HttpMessageConverter<?>> converters, @Nullable List<Object> requestResponseBodyAdvice) {
Assert.notEmpty(converters, "'messageConverters' must not be empty");
this.messageConverters = converters;
this.allSupportedMediaTypes = getAllSupportedMediaTypes(converters);
this.advice = new RequestResponseBodyAdviceChain(requestResponseBodyAdvice);
}

复制代码

// 生成日志信息，并放到request中
@ControllerAdvice
public class RequestBodyAdviceHandler implements RequestBodyAdvice {
public RequestBodyAdviceHandler() {
}
public boolean supports(MethodParameter methodParameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
Method method = methodParameter.getMethod();
Class<?> declaringClass = method.getDeclaringClass();
RestController RestController = (RestController)declaringClass.getAnnotation(RestController.class);
return RestController != null;
}
public HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) throws IOException {
return inputMessage;
}
public Object afterBodyRead(Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
this.writeRequestLog(body, inputMessage, parameter, targetType, converterType);
return body;
}
public Object handleEmptyBody(Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
this.writeRequestLog(body, inputMessage, parameter, targetType, converterType);
return body;
}
private String toJSONString(Object body, MethodParameter parameter) {
IgnoreLogBody ignore = (IgnoreLogBody)parameter.getMethodAnnotation(IgnoreLogBody.class);
if (ignore == null) {
return JSON.toJSONString(body);
} else {
String[] ignoreKey = ignore.ignoreKey();
return ignoreKey != null && ignoreKey.length != 0 ? JSON.toJSONString(body, new IgnoreLogPropertyFilter(ignore.ignoreKey(), ignore.key()), new SerializerFeature[0]) : JSON.toJSONString(body);
}
}
private void writeRequestLog(Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
HttpServletRequest request = RequestHelper.getRequest();
request.setAttribute("_REQUEST_STARTTIME_", System.currentTimeMillis());
String requestId = request.getHeader("_REQUEST_ID_");
if (StringUtils.isEmptyStr(requestId)) {
requestId = TraceContext.traceId();
}
if (StringUtils.isEmptyStr(requestId) || "Ignored_Trace".equals(requestId)) {
requestId = UUID.randomUUID().toString().replaceAll("-", "");
}
request.setAttribute("_REQUEST_ID_", requestId);
StringBuilder info = new StringBuilder("==>\n");
info.append("[*=请求requestID=]>: ").append(requestId).append("\n");
info.append("[==请求地址=======]>: ").append(request.getRequestURL().toString()).append("\n");
info.append("[==请求方法=======]>: ").append(request.getMethod()).append("\n");
info.append("[==操作用户=======]>: ").append(UserInfoContext.getCurrentUserCode()).append("\n");
info.append("[==客户IP========]>: ").append(RequestHelper.getClientIP()).append("\n");
info.append("[==映射方法=======]>: ").append(parameter.getMethod()).append(".").append("\n");
if (body == null) {
info.append("[==请求参数=======]>: ").append("该接口未定义参数或参数为空");
} else if (converterType == FastJsonHttpMessageConverter.class) {
info.append("[==请求参数=======]>: ").append(this.toJSONString(body, parameter));
} else {
info.append("[==请求参数=======]>: ").append(converterType);
}
info.append("\n");
request.setAttribute("_REQUEST_LOG_INFO_", info);
}
}

复制代码

@ControllerAdvice
public class ResponseBodyAdviceHandler implements ResponseBodyAdvice<Object> {
private static final IEventLogger logger = Logtube.getLogger(ResponseBodyAdviceHandler.class.getName());
public ResponseBodyAdviceHandler() {
}
public boolean supports(MethodParameter methodParamter, Class<? extends HttpMessageConverter<?>> converterType) {
return this.isRestController(methodParamter);
}
public Object beforeBodyWrite(Object body, MethodParameter methodParamter, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest req, ServerHttpResponse response) {
HttpServletRequest request = RequestHelper.getRequest();
if (request == null) {
return body;
} else {
StringBuilder info = (StringBuilder)request.getAttribute("_REQUEST_LOG_INFO_");
if (info == null) {
info = new StringBuilder();
}
String requestBodyData = null;
if (body == null) {
requestBodyData = null;
} else if (selectedContentType.includes(MediaType.APPLICATION_JSON)) {
requestBodyData = JSON.toJSONString(body);
} else {
requestBodyData = body.toString();
}
Long startTime = (Long)request.getAttribute("_REQUEST_STARTTIME_");
info.append("[==响应结果=======]>: ").append(requestBodyData == null ? "null" : requestBodyData);
info.append("\n");
if (startTime != null) {
info.append("[==执行耗时=======]>: ").append(System.currentTimeMillis() - startTime).append("ms").append("\n");
}
String requestId = (String)request.getAttribute("_REQUEST_ID_");
logger.info(info.toString());
return body;
}
}
private boolean isRestController(MethodParameter methodParamter) {
RestController annotation = (RestController)methodParamter.getDeclaringClass().getAnnotation(RestController.class);
return annotation != null;
}
}

复制代码

@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
// 选择返回的handler处理
HandlerMethodReturnValueHandler handler = selectHandler(returnValue, returnType);
if (handler == null) {
throw new IllegalArgumentException("Unknown return value type: " + returnType.getParameterType().getName());
}
// 执行handleReturnValue将数据写入到reponse流中
handler.handleReturnValue(returnValue, returnType, mavContainer, webRequest);
}

复制代码

// 被@ResponseBody注解的方法，会被执行该类
@Override
public boolean supportsReturnType(MethodParameter returnType) {
return (AnnotatedElementUtils.hasAnnotation(returnType.getContainingClass(), ResponseBody.class) ||
returnType.hasMethodAnnotation(ResponseBody.class));
}
//将returnValue写入到流中
@Override
public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
ModelAndViewContainer mavContainer, NativeWebRequest webRequest)
throws IOException, HttpMediaTypeNotAcceptableException, HttpMessageNotWritableException {
mavContainer.setRequestHandled(true);
ServletServerHttpRequest inputMessage = createInputMessage(webRequest);
ServletServerHttpResponse outputMessage = createOutputMessage(webRequest);
// Try even with null return value. ResponseBodyAdvice could get involved.
writeWithMessageConverters(returnValue, returnType, inputMessage, outputMessage);
}

复制代码