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 springboot 2.0 之前用
代码语言：javascript复制org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer
类来实现该功能。
使用 Java7 内部类的实现：
代码语言：javascript复制@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);
}
};
}Java8 的 lambda 表达式写法：
代码语言：javascript复制@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：
代码语言：javascript复制@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。
附录
- 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 相关类如下：
代码语言：javascript复制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.TomcatEmbeddedServletContainerFactoryspringboot2.x 相关类如下：
代码语言：javascript复制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
