springboot自定义404页面

添加配置类
java 复制代码
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import javax.servlet.Servlet;
import org.apache.catalina.startup.Tomcat;
import org.apache.catalina.valves.ErrorReportValve;
import org.apache.coyote.UpgradeProtocol;
import org.springframework.beans.BeansException;
import  org.springframework.beans.factory.config.BeanPostProcessor;
import  org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import  org.springframework.boot.autoconfigure.web.embedded.TomcatWebServerFactoryCustomizer;
import  org.springframework.boot.web.embedded.tomcat.ConfigurableTomcatWebServerFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.stereotype.Component;
import org.springframework.util.FileCopyUtils;
import lombok.extern.slf4j.Slf4j;
@ConditionalOnClass({ Servlet.class, Tomcat.class,  UpgradeProtocol.class,  TomcatWebServerFactoryCustomizer.class })
@Component
@Slf4j
public class TomcatCustomizerBeanPostProcessor implements  BeanPostProcessor {
     @Override
     public Object postProcessAfterInitialization(Object  bean, String beanName) throws BeansException {
          if (bean instanceof  ConfigurableTomcatWebServerFactory) {
              ConfigurableTomcatWebServerFactory  configurableTomcatWebServerFactory =  (ConfigurableTomcatWebServerFactory) bean;
              
              addTomcat404CodePage(configurableTomcatWebServerFactory);
          }
          return  BeanPostProcessor.super.postProcessAfterInitialization(bean, beanName);
     }
     private static void  addTomcat404CodePage(ConfigurableTomcatWebServerFactory  factory) {
          factory.addContextCustomizers((context) -> {
              String tomcatTempPath =  context.getCatalinaBase().getPath();
              log.info("tomcat目录：{}", tomcatTempPath);
              String path = tomcatTempPath + "/404.html";
              ClassPathResource cr = new  ClassPathResource("404.html");
              if (cr.exists()) {
                   File file404 = new File(path);
                   if (!file404.exists()) {
                        try {
                             FileCopyUtils.copy(cr.getInputStream(), new FileOutputStream(file404));
                        } catch (IOException e) {
                             e.printStackTrace();
                        }
                   }
              }
              ErrorReportValve valve = new  ErrorReportValve();
              valve.setProperty("errorCode.404", path);
              valve.setShowServerInfo(false);
              valve.setShowReport(false);
              valve.setAsyncSupported(true);
              context.getParent().getPipeline().addValve(valve);
          });
     }
}
在resources文件夹下直接添加404.html文件，再次启动测试，发现404页面已修改