【动态拦截@PostMapping注解,并且修改或新增value属性】

不仅可以拦截PostMapping 别的注解也可以

import java.lang.reflect.Field;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author：pys
 * @时间：2023年03月22日 14:14
 * @说明：动态修改RequestMapping注解
 */

@Slf4j
@Component
public class RequestMappingPrefixBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

  private static final String OLD_PREFIX = "/rest/rum";
  private static final String NEW_PREFIX = "/api/rum";
  private static final String VALUE = "value";
  private static final String MEMBER_VALUES = "memberValues";

  @Override
  public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
      throws BeansException {
    //获取RestController注解标注的bean
    String[] beanNames = beanFactory.getBeanNamesForAnnotation(RestController.class);
    for (String beanName : beanNames) {
      //获取Class
      Class<?> beanType = beanFactory.getType(beanName);
      //如果被RequestMapping标注
      if (beanType.isAnnotationPresent(RequestMapping.class)) {
        //获取注解
        RequestMapping annotation = beanType.getAnnotation(RequestMapping.class);
        //获取RequestMapping的所有路径
        String[] paths = annotation.value();
        List<String> newPathList = new ArrayList<>();
        //是否为 /rest/rum 开头的flag
        boolean addedNewPrefixFlag = false;
        String newPath = null;
        //遍历url路径
        for (String path : paths) {
          if (path.startsWith(OLD_PREFIX)) {
            log.info("old Annotation Value " + annotation.value()[0]);
            newPath = path.replace(OLD_PREFIX, NEW_PREFIX);
            //添加新的路径
            newPathList.add(newPath);
            addedNewPrefixFlag = true;
          }
          //添加老的路径
          newPathList.add(path);
          break;
        }
        //如果添加成功
        if (addedNewPrefixFlag && newPath != null) {
          //调转顺序 framework识别的是 path[0]的路径 所以要把/api/rum放前边 /rest/rum放后边
          newPathList.add(0, newPath);
          String[] newPaths = newPathList.toArray(new String[0]);
          Field f;
          try {
            //获取代理handler
            Object handler = Proxy.getInvocationHandler(annotation);
            //获取RequestMapping真正属性存值的地方
            f = handler.getClass().getDeclaredField(MEMBER_VALUES);
            f.setAccessible(true);
            Map<String, Object> memberValues;
            memberValues = (Map<String, Object>) f.get(handler);
            //替换value
            memberValues.put(VALUE, newPaths);
            log.info("New Annotation Value " + annotation.value()[0]);
          } catch (Exception e) {
            log.error("Failed to set annotation value: " + e.getMessage(), e);
          }
        }
      }
    }

  }
}