效果圖
參數攔截器:參數存在得情況
參數攔截器:參數不存在得情況
方法註解攔截器:控制檯日誌
源碼
package com.asyf.common;
import com.asyf.annotation.Login;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.lang.Nullable;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MyInterceptor implements HandlerInterceptor {
public static final Logger log = LoggerFactory.getLogger(MyInterceptor.class);
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
log.info("preHandle");
//如果是SpringMVC請求
if (handler instanceof HandlerMethod) {
HandlerMethod handlerMethod = (HandlerMethod) handler;
log.info("當前攔截的方法爲:{}", handlerMethod.getMethod().getName());
log.info("當前攔截的方法參數長度爲:{}", handlerMethod.getMethod().getParameters().length);
log.info("當前攔截的類爲:{}", handlerMethod.getBean().getClass().getName());
String uri = request.getRequestURI();
log.info("攔截的uri:" + uri);
//獲取方法註解
Login login = handlerMethod.getMethodAnnotation(Login.class);
if (login != null) {
log.info("login.required()---" + String.valueOf(login.required()));
}
}
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
log.info("postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
log.info("afterCompletion");
}
}
package com.asyf.common;
import com.asyf.annotation.Param;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.MethodParameter;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.MissingServletRequestParameterException;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
import javax.servlet.http.HttpServletRequest;
public class TestArgumentResolver implements HandlerMethodArgumentResolver {
public static final Logger log = LoggerFactory.getLogger(TestArgumentResolver.class);
@Override
public boolean supportsParameter(MethodParameter methodParameter) {
//如果函數包含我們的自定義註解,那就走resolveArgument()函數,可以支持多個註解
return methodParameter.hasParameterAnnotation(Param.class);
}
/**
* 根據註解得不同操作不同得業務
*/
@Override
public Object resolveArgument(MethodParameter methodParameter,
ModelAndViewContainer modelAndViewContainer,
NativeWebRequest nativeWebRequest,
WebDataBinderFactory webDataBinderFactory) throws Exception {
log.info("參數解析器--HandlerMethodArgumentResolver");
//獲取參數名
String parameterName = methodParameter.getParameterName();
log.info("parameterName---" + parameterName);
Class<?> parameterType = methodParameter.getParameterType();
Param param = methodParameter.getParameterAnnotation(Param.class);
boolean required = param.required();
//簡單的案例:如果客戶端未傳值,就設置默認值
Object res = nativeWebRequest.getNativeRequest(HttpServletRequest.class).getParameter(parameterName);
log.info("res---" + res);
//判斷參數是否存在
if (required) {
if (StringUtils.isEmpty(res)) {
throw new MissingServletRequestParameterException(parameterName, parameterType.toString());
}
}
//返回值就是controller接收得值
return res;
}
}
package com.asyf.common;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import java.util.List;
@Configuration
public class WebConfig implements WebMvcConfigurer {
@Override
public void addInterceptors(InterceptorRegistry registry) {
//'/**'匹配所有
registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**");
}
@Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
resolvers.add(new TestArgumentResolver());
}
}
@RequestMapping(value = "demo")
@Login
public Map<String, String> demo(@Param(required = true) String a) {
Map<String, String> map = new HashMap<>();
map.put("time", new Date().toString());
map.put("a", a);
return map;
}
package com.asyf.annotation;
import java.lang.annotation.*;
@Documented
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface Param {
boolean required() default false;
}