springboot 自定义错误页面

Spring Boot默认使用嵌入式Tomcat，默认没有页面来处理404等常见错误。因此，为了给用户最佳的使用体验，404等常见错误需要我们自定义页面来处理。

在springboot2.0之前用org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer类来实现该功能。

使用Java 7内部类的实现：

@Bean
public EmbeddedServletContainerCustomizer containerCustomizer() {
    return new EmbeddedServletContainerCustomizer() {
        @Override
        public void customize(ConfigurableEmbeddedServletContainer container) {

            ErrorPage error401Page = new ErrorPage(HttpStatus.UNAUTHORIZED, "/401.html");
            ErrorPage error404Page = new ErrorPage(HttpStatus.NOT_FOUND, "/404.html");
            ErrorPage error500Page = new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/500.html");

            container.addErrorPages(error401Page, error404Page, error500Page);
        }
    };
}

Java 8的lambda表达式写法：

@Bean
public EmbeddedServletContainerCustomizer containerCustomizer() {

   return (container -> {
        ErrorPage error401Page = new ErrorPage(HttpStatus.UNAUTHORIZED, "/401.html");
        ErrorPage error404Page = new ErrorPage(HttpStatus.NOT_FOUND, "/404.html");
        ErrorPage error500Page = new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/500.html");

        container.addErrorPages(error401Page, error404Page, error500Page);
   });
}

在代码中创建了三个ErrorPage实例来处理三个通用的HTTP错误状态码，并将他们添加到container当中。ErrorPage类是一个封装了错误信息的类，它可以在Jetty和Tomcat环境下使用。

错误页面需要放在项目static内容目录下，它的默认位置是：src/main/resources/static，如下图所示：

在Spring Boot2.0以上配置嵌入式Servlet容器时EmbeddedServletContainerCustomizer类不存在，被WebServerFactoryCustomizer替代

       使用WebServerFactoryCustomizer接口替换EmbeddedServletContainerCustomizer组件完成对嵌入式Servlet容器的配置，示例代码如下：

@Bean
 
public WebServerFactoryCustomizer<ConfigurableWebServerFactory> webServerFactoryCustomizer(){　

　　return (container -> {
    　　ErrorPage error401Page = new ErrorPage(HttpStatus.UNAUTHORIZED, "/error/401.html");
    　　ErrorPage error404Page = new ErrorPage(HttpStatus.NOT_FOUND, "/error/404.html");
    　　ErrorPage error500Page = new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/error/500.html");

    　　container.addErrorPages(error401Page, error404Page, error500Page);
　　});

 }

在WebServerFactoryCustomizer接口中使用ConfigurableWebServerFactory对象实现对customize()方法的转换，从而实现对嵌入式servlet容器的配置。

附注：

springboot 1.x

import org.apache.catalina.connector.Connector;
import org.apache.coyote.ProtocolHandler;
import org.apache.coyote.http11.Http11NioProtocol;
import org.apache.tomcat.util.threads.ThreadPoolExecutor;
import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
import org.springframework.boot.web.servlet.ErrorPage;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;


@Component
public class EmbeddedTomcatConfig implements EmbeddedServletContainerCustomizer{

    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) {
        TomcatEmbeddedServletContainerFactory factory = (TomcatEmbeddedServletContainerFactory)container;
        factory.addConnectorCustomizers(new TomcatConnectorCustomizer() {
            @Override
            public void customize(Connector connector) {
                Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();
                protocol.setMaxConnections(200);
                protocol.setMaxThreads(200);
                protocol.setSelectorTimeout(3000);
                protocol.setSessionTimeout(3000);
                protocol.setConnectionTimeout(3000);
            }
        });
    }
}

通过实现org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer的customize方法来实现自定义

springboot 2.x

import org.apache.catalina.connector.Connector;
import org.apache.coyote.ProtocolHandler;
import org.apache.coyote.http11.Http11NioProtocol;
import org.apache.tomcat.util.threads.ThreadPoolExecutor;
import org.springframework.boot.web.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;


@Component
public class EmbeddedTomcatConfig implements WebServerFactoryCustomizer<ConfigurableServletWebServerFactory> {

    @Override
    public void customize(ConfigurableServletWebServerFactory factory) {
        ((TomcatServletWebServerFactory)factory).addConnectorCustomizers(new TomcatConnectorCustomizer() {
            @Override
            public void customize(Connector connector) {
                Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();
                protocol.setMaxConnections(200);
                protocol.setMaxThreads(200);
                protocol.setSelectorTimeout(3000);
                protocol.setSessionTimeout(3000);
                protocol.setConnectionTimeout(3000);
            }
        });
    }
}

在2.x版本改为实现org.springframework.boot.web.server.WebServerFactoryCustomizer接口的customize方法

springboot1.x的相关类如下：

• org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer
• org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer
• org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer
• org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory

springboot2.x的相关类如下：

• org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory
• org.springframework.boot.web.server.WebServerFactoryCustomizer
• org.springframework.boot.web.embedded.tomcat.TomcatConnectorCustomizer
• org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory