java - 如果 AppContext 初始化失败，正确终止 Spring Boot 和 Tomcat

Question

当我在嵌入式 Tomcat 上启动 Spring Boot 应用程序并且在启动过程中出现某些问题时(例如没有连接到 DB 或 Liquibase 更新失败或发现循环依赖等)，Tomcat 继续监听 8080 端口。

如果我向某个端点发送 HTTP 请求，应用程序会返回 404 NOT FOUND。

1. 这是预期的行为吗(Tomcat 应该继续监听)吗？
2. 如何在应用上下文初始化失败时停止Spring Boot和Tomcat？

这里是日志的例子:

org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tomcatEmbeddedServletContainerFactory' defined in class path resource [org/springframework/boot/autoconfigure/web/EmbeddedServletContainerAutoConfiguration$EmbeddedTomcat.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'serverProperties' defined in class path resource [org/springframework/boot/autoconfigure/web/ServerPropertiesAutoConfiguration.class]: Initialization of bean failed; nested exception is javax.validation.ValidationException: Unable to instantiate Configuration.
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:137)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:536)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107)
    at com.test.Application.main(Application.java:33)

在此异常之后，Tomcat 在指定端口上仍然可用。

UPD

应用程序属性:

spring.profiles.default=production
spring.application.name=test

spring.datasource.url=jdbc:postgresql://localhost:5432/testdb
spring.datasource.username=test
spring.datasource.password=test123
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect

spring.jpa.hibernate.ddl-auto=none

liquibase.change-log=classpath:/liquibase/changelog.xml

依赖关系:

<properties>
    <spring.boot.version>1.5.9.RELEASE</spring.boot.version>

    <liquibase.version>3.5.3</liquibase.version>
    <postgresql.version>9.4-1201-jdbc41</postgresql.version>
    <hsqldb.version>2.4.0</hsqldb.version>

    <powermock.version>1.7.3</powermock.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>${spring.boot.version}</version>
        <exclusions>
            <exclusion>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-el</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.apache.tomcat</groupId>
                <artifactId>tomcat-annotations-api</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
        <version>${spring.boot.version}</version>
        <exclusions>
            <exclusion>
                <groupId>org.apache.tomcat</groupId>
                <artifactId>tomcat-juli</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
        <version>${spring.boot.version}</version>
        <exclusions>
            <exclusion>
                <groupId>org.codehaus.groovy</groupId>
                <artifactId>groovy</artifactId>
            </exclusion>
            <exclusion>
                <groupId>nz.net.ultraq.thymeleaf</groupId>
                <artifactId>thymeleaf-layout-dialect</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-autoconfigure</artifactId>
        <version>${spring.boot.version}</version>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
        <version>${spring.boot.version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <version>${spring.boot.version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>4.3.14.RELEASE</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <version>${postgresql.version}</version>
    </dependency>

    <dependency>
        <groupId>org.liquibase</groupId>
        <artifactId>liquibase-core</artifactId>
        <version>${liquibase.version}</version>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.hsqldb</groupId>
        <artifactId>hsqldb</artifactId>
        <version>${hsqldb.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-module-junit4</artifactId>
        <version>${powermock.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.powermock</groupId>
        <artifactId>powermock-api-mockito</artifactId>
        <version>${powermock.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.hamcrest</groupId>
        <artifactId>hamcrest-library</artifactId>
        <version>${hamcrest.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.hamcrest</groupId>
        <artifactId>hamcrest-core</artifactId>
        <version>${hamcrest.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>com.google.code.simple-spring-memcached</groupId>
        <artifactId>spring-cache</artifactId>
        <version>3.6.1</version>
        <exclusions>
            <exclusion>
                <groupId>org.hamcrest</groupId>
                <artifactId>hamcrest-core</artifactId>
            </exclusion>
            <exclusion>
                <groupId>commons-collections</groupId>
                <artifactId>commons-collections</artifactId>
            </exclusion>
            <exclusion>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.codehaus.janino</groupId>
        <artifactId>janino</artifactId>
        <version>3.0.8</version>
    </dependency>

    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.2.3</version>
    </dependency>

    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-core</artifactId>
        <version>1.2.3</version>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>${spring.boot.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

UPD 2

应用程序.java:

@SpringBootApplication
@EnableJpaRepositories(basePackages = "com.test")
@EnableCaching
@EnableScheduling
public class Application extends SpringBootServletInitializer {

    public Application() {
    }

    public static void main(final String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Answer 1

这可能有两种情况

First Scenario

应用程序已启动并正在运行，创建了 App Context，然后服务器中发生了一些运行时异常，您想要正常关闭。在这种情况下，您可以使用类似 Spring boot Graceful shutdown 的实用程序

Scenario 2:

这是当 Spring Boot 无法自行创建应用程序上下文时发生的场景。您的场景属于此类。当应用程序启动时，它会尝试从 application.properties 连接配置，如果有任何问题，应用程序上下文本身将不会被创建

因此在这种情况下，您不能选择正常关闭，因为您没有应用程序上下文实例。在这种情况下，您可以捕获异常，选择适当的日志记录并手动退出系统

       try{
           SpringApplication.run(Application.class, args).close();;
        }
        catch(Exception ex){
            System.out.println("Going to exit");
            System.exit(-1);
        }

在此之后，Tomcat 实例将不会运行，端口将可以使用