Spring Boot Web应用程序中注册 Servlet 的方法实例
本文实例工程源代码：https://github.com/KotlinSpringBoot/demo1_add_servlet
我们对如何创建Controller 来响应JSON 以及如何显示数据到页面中，已经很熟悉了。
Web开发使用 Controller 基本上可以完成大部分需求，但是我们还可能会用到 Servlet、Filter、Listener、Interceptor 等等。
当使用spring-Boot时，嵌入式Servlet容器通过扫描注解的方式注册Servlet、Filter和Servlet规范的所有监听器（如HttpSessionListener监听器）。
Spring boot 的主 Servlet 为 DispatcherServlet，其默认的url-pattern为“/”。也许我们在应用中还需要定义更多的Servlet，该如何使用SpringBoot来完成呢？
在spring boot中添加自己的Servlet有两种方法，代码注册Servlet和注解自动注册（Filter和Listener也是如此）。
一、代码注册通过ServletRegistrationBean、 FilterRegistrationBean 和 ServletListenerRegistrationBean 获得控制。
也可以通过实现 ServletContextInitializer 接口直接注册。
二、在 SpringBootApplication 上使用@ServletComponentScan 注解后，Servlet、Filter、Listener 可以直接通过 @WebServlet、@WebFilter、@WebListener 注解自动注册，无需其他代码。
通过代码注册Servlet示例
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Demo1AddServletApplication.kt
package com.easy.springboot.demo1_add_servlet
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
@SpringBootApplication
class Demo1AddServletApplication
fun main(args: Array<String>) {
runApplication<Demo1AddServletApplication>(*args)
}
build.gradle
buildscript {
ext {
kotlinVersion = '1.2.0'
springBootVersion = '2.0.0.M7'
}
repositories {
mavenCentral()
maven { url "https://repo.spring.io/snapshot" }
maven { url "https://repo.spring.io/milestone" }
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
classpath("org.jetbrains.kotlin:kotlin-allopen:${kotlinVersion}")
}
}
apply plugin: 'kotlin'
apply plugin: 'kotlin-spring'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'com.easy.springboot'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
compileKotlin {
kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
kotlinOptions.jvmTarget = "1.8"
}
repositories {
mavenCentral()
maven { url "https://repo.spring.io/snapshot" }
maven { url "https://repo.spring.io/milestone" }
}
dependencies {
compile('org.springframework.boot:spring-boot-starter-web')
compile("org.jetbrains.kotlin:kotlin-stdlib-jre8")
compile("org.jetbrains.kotlin:kotlin-reflect")
testCompile('org.springframework.boot:spring-boot-starter-test')
}
工程目录
demo1_add_servlet$ tree
.
├── build
│ ├── kotlin
│ │ ├── compileKotlin
│ │ └── compileTestKotlin
│ └── kotlin-build
│ └── version.txt
├── build.gradle
├── demo1_add_servlet.iml
├── demo1_add_servlet.ipr
├── demo1_add_servlet.iws
├── demo1_add_servlet_main.iml
├── demo1_add_servlet_test.iml
├── gradle
│ └── wrapper
│ ├── gradle-wrapper.jar
│ └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── out
│ └── production
│ ├── classes
│ │ ├── META-INF
│ │ │ └── demo1_add_servlet_main.kotlin_module
│ │ └── com
│ │ └── easy
│ │ └── springboot
│ │ └── demo1_add_servlet
│ │ ├── Demo1AddServletApplication.class
│ │ └── Demo1AddServletApplicationKt.class
│ └── resources
│ └── application.properties
└── src
├── main
│ ├── java
│ ├── kotlin
│ │ └── com
│ │ └── easy
│ │ └── springboot
│ │ └── demo1_add_servlet
│ │ └── Demo1AddServletApplication.kt
│ └── resources
│ ├── application.properties
│ ├── static
│ └── templates
└── test
├── java
├── kotlin
│ └── com
│ └── easy
│ └── springboot
│ └── demo1_add_servlet
│ └── Demo1AddServletApplicationTests.kt
└── resources
35 directories, 18 files
启动应用
/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/bin/java -XX:TieredStopAtLevel=1 -noverify -Dspring.output.ansi.enabled=always -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=51448 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Djava.rmi.server.hostname=127.0.0.1 -Dspring.liveBeansView.mbeanDomain -Dspring.application.admin.enabled=true "-javaagent:/Applications/IntelliJ IDEA.app/Contents/lib/idea_rt.jar=51449:/Applications/IntelliJ IDEA.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath /Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/deploy.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/cldrdata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/dnsns.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/jfxrt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/localedata.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/nashorn.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/sunec.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/sunjce_provider.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/sunpkcs11.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/ext/zipfs.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/javaws.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/jfxswt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/management-agent.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/plugin.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/ant-javafx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/dt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/javafx-mx.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/jconsole.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/packager.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/sa-jdi.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/lib/tools.jar:/Users/jack/KotlinSpringBoot/demo1_add_servlet/out/production/classes:/Users/jack/KotlinSpringBoot/demo1_add_servlet/out/production/resources:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-starter-web/2.0.0.M7/eb364c43417c6de883c38ffc9d79b91a63c9c3bd/spring-boot-starter-web-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jre8/1.1.61/7cb0d1b54614623a4b297af1eea7bc3aa0e9e63/kotlin-stdlib-jre8-1.1.61.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-reflect/1.1.61/bb6da1a122c3fba2f7ee5c71946441e4f756fad4/kotlin-reflect-1.1.61.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-starter-json/2.0.0.M7/7f352d7960cbe1a341e0721625dddb1bca6c5313/spring-boot-starter-json-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-starter/2.0.0.M7/b9affaea8ab21294386d5c2682b66f143852878d/spring-boot-starter-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-starter-tomcat/2.0.0.M7/709f5f42c3cfdc6d5a5d6921b7bcb7714f8d638c/spring-boot-starter-tomcat-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.hibernate.validator/hibernate-validator/6.0.5.Final/c0a53a8178a0487c5f2fe84434b9965a3cd44f22/hibernate-validator-6.0.5.Final.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework/spring-webmvc/5.0.2.RELEASE/8dbe4a28cae3ffa222aeff6776a3928a88d66e6f/spring-webmvc-5.0.2.RELEASE.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework/spring-web/5.0.2.RELEASE/eea8edef792fb93c1c55cc61078ce14ffb3542df/spring-web-5.0.2.RELEASE.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jre7/1.1.61/59dfce93b1995717338435dd974884007d8e8474/kotlin-stdlib-jre7-1.1.61.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.1.61/fa7813a26c548c9c412dd2d42fb466cfcd8dcf3c/kotlin-stdlib-1.1.61.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-autoconfigure/2.0.0.M7/db2360882ec36c119c4378d01b0325a833b07271/spring-boot-autoconfigure-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot/2.0.0.M7/b1e1ad98517ae8988dd578b3ae2e2705c8f5634/spring-boot-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework.boot/spring-boot-starter-logging/2.0.0.M7/328a8032b5ed852958d410dec02638c0a93b3cb1/spring-boot-starter-logging-2.0.0.M7.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/javax.annotation/javax.annotation-api/1.3.1/20a2c0583598d68b0835474bbe07792d4f3b219f/javax.annotation-api-1.3.1.jar:/Users/jack/.gradle/caches/modules-2/files-2.1/org.springframework/spring-context/5.0.2.RELEASE/743a5f6d94a8af5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com.easy.springboot.demo1_add_servlet.Demo1AddServletApplicationKt
objc[30612]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/bin/java (0x10c75a4c0) and /Library/Java/JavaVirtualMachines/jdk1.8.0_40/Contents/Home/jre/lib/libinstrument.dylib (0x10dfb74e0). One of the two will be used. Which one is undefined.
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\/ )| |)| | | | | || (| | ) ) ) )
' |____| .|| ||| |_, | / / / /
=========||==============|/=////
:: Spring Boot :: (v2.0.0.M7)
2017-12-31 13:51:44.939 INFO 30612 --- [ main] c.e.s.d.Demo1AddServletApplicationKt : Starting Demo1AddServletApplicationKt on jacks-MacBook-Air.local with PID 30612 (/Users/jack/KotlinSpringBoot/demo1_add_servlet/out/production/classes started by jack in /Users/jack/KotlinSpringBoot/demo1_add_servlet)
2017-12-31 13:51:44.944 INFO 30612 --- [ main] c.e.s.d.Demo1AddServletApplicationKt : No active profile set, falling back to default profiles: default
2017-12-31 13:51:45.100 INFO 30612 --- [ main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@63355449: startup date [Sun Dec 31 13:51:45 CST 2017]; root of context hierarchy
2017-12-31 13:51:45.364 WARN 30612 --- [kground-preinit] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:46.101 WARN 30612 --- [kground-preinit] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:48.480 INFO 30612 --- [ main] o.h.v.i.engine.ValidatorFactoryImpl : HV000238: Temporal validation tolerance set to 0.
2017-12-31 13:51:49.411 INFO 30612 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2017-12-31 13:51:49.443 INFO 30612 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2017-12-31 13:51:49.446 INFO 30612 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.23
2017-12-31 13:51:49.478 INFO 30612 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/Users/jack/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.]
2017-12-31 13:51:49.659 INFO 30612 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2017-12-31 13:51:49.660 INFO 30612 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 4574 ms
2017-12-31 13:51:49.833 WARN 30612 --- [ost-startStop-1] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:49.884 INFO 30612 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2017-12-31 13:51:49.892 INFO 30612 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/]
2017-12-31 13:51:49.893 INFO 30612 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/]
2017-12-31 13:51:49.894 INFO 30612 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/]
2017-12-31 13:51:49.894 INFO 30612 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/]
2017-12-31 13:51:50.063 WARN 30612 --- [ main] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:50.167 INFO 30612 --- [ main] o.h.v.i.engine.ValidatorFactoryImpl : HV000238: Temporal validation tolerance set to 0.
2017-12-31 13:51:50.296 WARN 30612 --- [ main] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:50.353 WARN 30612 --- [ main] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:50.355 WARN 30612 --- [ main] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:50.436 INFO 30612 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@63355449: startup date [Sun Dec 31 13:51:45 CST 2017]; root of context hierarchy
2017-12-31 13:51:50.607 INFO 30612 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-12-31 13:51:50.608 INFO 30612 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-12-31 13:51:50.651 INFO 30612 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-12-31 13:51:50.651 INFO 30612 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-12-31 13:51:50.669 WARN 30612 --- [ main] o.s.h.c.j.Jackson2ObjectMapperBuilder : For Jackson Kotlin classes support please add "com.fasterxml.jackson.module:jackson-module-kotlin" to the classpath
2017-12-31 13:51:50.711 INFO 30612 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-12-31 13:51:50.955 INFO 30612 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2017-12-31 13:51:51.083 INFO 30612 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2017-12-31 13:51:51.089 INFO 30612 --- [ main] c.e.s.d.Demo1AddServletApplicationKt : Started Demo1AddServletApplicationKt in 8.173 seconds (JVM running for 10.559)
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package org.springframework.boot.autoconfigure.web.servlet.error;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.Servlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.aop.framework.autoproxy.AutoProxyUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionMessage;
import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.condition.SearchStrategy;
import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider;
import org.springframework.boot.autoconfigure.template.TemplateAvailabilityProviders;
import org.springframework.boot.autoconfigure.web.ResourceProperties;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.server.ErrorPage;
import org.springframework.boot.web.server.ErrorPageRegistrar;
import org.springframework.boot.web.server.ErrorPageRegistry;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.error.DefaultErrorAttributes;
import org.springframework.boot.web.servlet.error.ErrorAttributes;
import org.springframework.boot.web.servlet.error.ErrorController;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.expression.MapAccessor;
import org.springframework.core.Ordered;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.PropertyPlaceholderHelper.PlaceholderResolver;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.view.BeanNameViewResolver;
import org.springframework.web.util.HtmlUtils;
/**
* {@link EnableAutoConfiguration Auto-configuration} to render errors via an MVC error
* controller.
*
* @author Dave Syer
* @author Andy Wilkinson
* @author Stephane Nicoll
*/
@Configuration
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class })
// Load before the main WebMvcAutoConfiguration so that the error View is available
@AutoConfigureBefore(WebMvcAutoConfiguration.class)
@EnableConfigurationProperties({ ServerProperties.class, ResourceProperties.class })
public class ErrorMvcAutoConfiguration {
private final ServerProperties serverProperties;
private final List<ErrorViewResolver> errorViewResolvers;
public ErrorMvcAutoConfiguration(ServerProperties serverProperties,
ObjectProvider<List<ErrorViewResolver>> errorViewResolversProvider) {
this.serverProperties = serverProperties;
this.errorViewResolvers = errorViewResolversProvider.getIfAvailable();
}
@Bean
@ConditionalOnMissingBean(value = ErrorAttributes.class, search = SearchStrategy.CURRENT)
public DefaultErrorAttributes errorAttributes() {
return new DefaultErrorAttributes(
this.serverProperties.getError().isIncludeException());
}
@Bean
@ConditionalOnMissingBean(value = ErrorController.class, search = SearchStrategy.CURRENT)
public BasicErrorController basicErrorController(ErrorAttributes errorAttributes) {
return new BasicErrorController(errorAttributes, this.serverProperties.getError(),
this.errorViewResolvers);
}
@Bean
public ErrorPageCustomizer errorPageCustomizer() {
return new ErrorPageCustomizer(this.serverProperties);
}
@Bean
public static PreserveErrorControllerTargetClassPostProcessor preserveErrorControllerTargetClassPostProcessor() {
return new PreserveErrorControllerTargetClassPostProcessor();
}
@Configuration
static class DefaultErrorViewResolverConfiguration {
private final ApplicationContext applicationContext;
private final ResourceProperties resourceProperties;
DefaultErrorViewResolverConfiguration(ApplicationContext applicationContext,
ResourceProperties resourceProperties) {
this.applicationContext = applicationContext;
this.resourceProperties = resourceProperties;
}
@Bean
@ConditionalOnBean(DispatcherServlet.class)
@ConditionalOnMissingBean
public DefaultErrorViewResolver conventionErrorViewResolver() {
return new DefaultErrorViewResolver(this.applicationContext,
this.resourceProperties);
}
}
@Configuration
@ConditionalOnProperty(prefix = "server.error.whitelabel", name = "enabled", matchIfMissing = true)
@Conditional(ErrorTemplateMissingCondition.class)
protected static class WhitelabelErrorViewConfiguration {
private final SpelView defaultErrorView = new SpelView(
"<html><body><h1>Whitelabel Error Page</h1>"
+ "<p>This application has no explicit mapping for /error, so you are seeing this as a fallback.</p>"
+ "<div id='created'>${timestamp}</div>"
+ "<div>There was an unexpected error (type=${error}, status=${status}).</div>"
+ "<div>${message}</div></body></html>");
@Bean(name = "error")
@ConditionalOnMissingBean(name = "error")
public View defaultErrorView() {
return this.defaultErrorView;
}
// If the user adds @EnableWebMvc then the bean name view resolver from
// WebMvcAutoConfiguration disappears, so add it back in to avoid disappointment.
@Bean
@ConditionalOnMissingBean(BeanNameViewResolver.class)
public BeanNameViewResolver beanNameViewResolver() {
BeanNameViewResolver resolver = new BeanNameViewResolver();
resolver.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
return resolver;
}
}
/**
* {@link SpringBootCondition} that matches when no error template view is detected.
*/
private static class ErrorTemplateMissingCondition extends SpringBootCondition {
@Override
public ConditionOutcome getMatchOutcome(ConditionContext context,
AnnotatedTypeMetadata metadata) {
ConditionMessage.Builder message = ConditionMessage
.forCondition("ErrorTemplate Missing");
TemplateAvailabilityProviders providers = new TemplateAvailabilityProviders(
context.getClassLoader());
TemplateAvailabilityProvider provider = providers.getProvider("error",
context.getEnvironment(), context.getClassLoader(),
context.getResourceLoader());
if (provider != null) {
return ConditionOutcome
.noMatch(message.foundExactly("template from " + provider));
}
return ConditionOutcome
.match(message.didNotFind("error template view").atAll());
}
}
/**
* Simple {@link View} implementation that resolves variables as SpEL expressions.
*/
private static class SpelView implements View {
private final NonRecursivePropertyPlaceholderHelper helper;
private final String template;
private volatile Map<String, Expression> expressions;
SpelView(String template) {
this.helper = new NonRecursivePropertyPlaceholderHelper("${", "}");
this.template = template;
}
@Override
public String getContentType() {
return "text/html";
}
@Override
public void render(Map<String, ?> model, HttpServletRequest request,
HttpServletResponse response) throws Exception {
if (response.getContentType() == null) {
response.setContentType(getContentType());
}
Map<String, Object> map = new HashMap<>(model);
map.put("path", request.getContextPath());
PlaceholderResolver resolver = new ExpressionResolver(getExpressions(), map);
String result = this.helper.replacePlaceholders(this.template, resolver);
response.getWriter().append(result);
}
private Map<String, Expression> getExpressions() {
if (this.expressions == null) {
synchronized (this) {
ExpressionCollector expressionCollector = new ExpressionCollector();
this.helper.replacePlaceholders(this.template, expressionCollector);
this.expressions = expressionCollector.getExpressions();
}
}
return this.expressions;
}
}
/**
* {@link PlaceholderResolver} to collect placeholder expressions.
*/
private static class ExpressionCollector implements PlaceholderResolver {
private final SpelExpressionParser parser = new SpelExpressionParser();
private final Map<String, Expression> expressions = new HashMap<>();
@Override
public String resolvePlaceholder(String name) {
this.expressions.put(name, this.parser.parseExpression(name));
return null;
}
public Map<String, Expression> getExpressions() {
return Collections.unmodifiableMap(this.expressions);
}
}
/**
* SpEL based {@link PlaceholderResolver}.
*/
private static class ExpressionResolver implements PlaceholderResolver {
private final Map<String, Expression> expressions;
private final EvaluationContext context;
ExpressionResolver(Map<String, Expression> expressions, Map<String, ?> map) {
this.expressions = expressions;
this.context = getContext(map);
}
private EvaluationContext getContext(Map<String, ?> map) {
StandardEvaluationContext context = new StandardEvaluationContext();
context.addPropertyAccessor(new MapAccessor());
context.setRootObject(map);
return context;
}
@Override
public String resolvePlaceholder(String placeholderName) {
Expression expression = this.expressions.get(placeholderName);
return escape(expression == null ? null : expression.getValue(this.context));
}
private String escape(Object value) {
return HtmlUtils.htmlEscape(value == null ? null : value.toString());
}
}
/**
* {@link WebServerFactoryCustomizer} that configures the server's error pages.
*/
private static class ErrorPageCustomizer implements ErrorPageRegistrar, Ordered {
private final ServerProperties properties;
protected ErrorPageCustomizer(ServerProperties properties) {
this.properties = properties;
}
@Override
public void registerErrorPages(ErrorPageRegistry errorPageRegistry) {
ErrorPage errorPage = new ErrorPage(
this.properties.getServlet().getServletPrefix()
+ this.properties.getError().getPath());
errorPageRegistry.addErrorPages(errorPage);
}
@Override
public int getOrder() {
return 0;
}
}
/**
* {@link BeanFactoryPostProcessor} to ensure that the target class of ErrorController
* MVC beans are preserved when using AOP.
*/
static class PreserveErrorControllerTargetClassPostProcessor
implements BeanFactoryPostProcessor {
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
throws BeansException {
String[] errorControllerBeans = beanFactory
.getBeanNamesForType(ErrorController.class, false, false);
for (String errorControllerBean : errorControllerBeans) {
try {
beanFactory.getBeanDefinition(errorControllerBean).setAttribute(
AutoProxyUtils.PRESERVE_TARGET_CLASS_ATTRIBUTE, Boolean.TRUE);
}
catch (Throwable ex) {
// Ignore
}
}
}
}
}
exclude, 有异常不会找默认error页面了，而是直接输出字符串
package com.easy.springboot.demo1_add_servlet
import org.springframework.boot.autoconfigure.EnableAutoConfiguration
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration
import org.springframework.boot.runApplication
@SpringBootApplication
@EnableAutoConfiguration(exclude = [ErrorMvcAutoConfiguration::class]) // exclude, 有异常不会找默认error页面了，而是直接输出字符串
class Demo1AddServletApplication
fun main(args: Array<String>) {
runApplication<Demo1AddServletApplication>(*args)
}
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HelloWorldServlet.kt
package com.easy.springboot.demo1_add_servlet.servlet
import com.fasterxml.jackson.databind.ObjectMapper
import javax.servlet.annotation.WebServlet
import javax.servlet.http.HttpServlet
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse
@WebServlet(urlPatterns=["/hello"])
class HelloWorldServlet : HttpServlet() {
override fun doGet(req: HttpServletRequest, resp: HttpServletResponse) {
println("Invoke doGet: req = $req, resp = $resp")
doPost(req, resp)
}
override fun doPost(req: HttpServletRequest, resp: HttpServletResponse) {
println("Invoke doPost: req = $req, resp = $resp")
resp.contentType = "application/json"
val om = ObjectMapper()
val resultJson = om.writeValueAsString(User("你好，World", "10000000001"))
val out = resp.writer
out.println(resultJson)
}
data class User(var username: String, var id: String)
}
@WebServlet(urlPatterns=["/hello"])
@ServletComponentScan
package com.easy.springboot.demo1_add_servlet
import org.springframework.boot.autoconfigure.EnableAutoConfiguration
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration
import org.springframework.boot.runApplication
import org.springframework.boot.web.servlet.ServletComponentScan
@SpringBootApplication
@EnableAutoConfiguration(exclude = [ErrorMvcAutoConfiguration::class]) // exclude, 有异常不会找默认error页面了，而是直接输出字符串
@ServletComponentScan
class Demo1AddServletApplication
fun main(args: Array<String>) {
runApplication<Demo1AddServletApplication>(*args)
}
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中文乱码：
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ISO-8859-1是单字节编码，自身不能显示中文。
ISO-8859-1编码是单字节编码，向下兼容ASCII，其编码范围是0x00-0xFF，0x00-0x7F之间完全和ASCII一致，0x80-0x9F之间是控制字符，0xA0-0xFF之间是文字符号。
此字符集支持部分于欧洲使用的语言，包括阿尔巴尼亚语、巴斯克语、布列塔尼语、加泰罗尼亚语、丹麦语、荷兰语、法罗语、弗里西语、加利西亚语、德语、格陵兰语、冰岛语、爱尔兰盖尔语、意大利语、拉丁语、卢森堡语、挪威语、葡萄牙语、里托罗曼斯语、苏格兰盖尔语、西班牙语及瑞典语。
package com.easy.springboot.demo1_add_servlet.servlet
import com.fasterxml.jackson.databind.ObjectMapper
import javax.servlet.annotation.WebServlet
import javax.servlet.http.HttpServlet
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse
@WebServlet(urlPatterns = ["/hello"])
class HelloWorldServlet : HttpServlet() {
override fun doGet(req: HttpServletRequest, resp: HttpServletResponse) {
println("Invoke doGet: req.requestURI = ${req.requestURI}, resp.contentType = ${resp.contentType}")
doPost(req, resp)
}
override fun doPost(req: HttpServletRequest, resp: HttpServletResponse) {
println("Invoke doPost ===> ")
resp.contentType = "application/json;charset=UTF-8"
val om = ObjectMapper()
val resultJson = om.writeValueAsString(User("你好，World", "10000000001"))
val out = resp.writer
out.println(resultJson)
}
data class User(var username: String, var id: String)
}
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后台日志：
2017-12-31 15:14:46.592 INFO 31698 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2017-12-31 15:14:46.598 INFO 31698 --- [ main] c.e.s.d.Demo1AddServletApplicationKt : Started Demo1AddServletApplicationKt in 6.82 seconds (JVM running for 7.848)
Invoke doGet: req.requestURI = /hello, resp.contentType = null
Invoke doPost ===>
如果不加注解 @ServletComponentScan
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这个 Servlet 将不会被注册：
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/** 采用 @Configuration + @Bean 注解的方式 */
package com.easy.springboot.demo1_add_servlet.servlet
import com.fasterxml.jackson.databind.ObjectMapper
import org.springframework.boot.web.servlet.ServletRegistrationBean
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import javax.servlet.http.HttpServlet
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse
// 不使用 @WebServlet(urlPatterns = ["/what"])
class WhatServlet : HttpServlet() {
override fun doGet(req: HttpServletRequest, resp: HttpServletResponse) {
println("Invoke doGet: req.requestURI = ${req.requestURI}, resp.contentType = ${resp.contentType}")
doPost(req, resp)
}
override fun doPost(req: HttpServletRequest, resp: HttpServletResponse) {
println("Invoke doPost ===> ")
resp.contentType = "application/json;charset=UTF-8"
val om = ObjectMapper()
val resultJson = om.writeValueAsString(What("What Servlet?", "10000000002"))
val out = resp.writer
out.println(resultJson)
}
data class What(var name: String, var id: String)
}
/** 采用 @Configuration + @Bean 注解的方式 */
@Configuration
class ServletConfig {
@Bean
fun servletRegistrationBean(): ServletRegistrationBean<*> {
return ServletRegistrationBean(WhatServlet(), "/what")
}
}
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标签：Web,Boot,boot,springframework,jar,Spring,org,import,servlet From： https://blog.51cto.com/u_15236724/5766912