Ektorp 依赖项崩溃 Spring 启动应用程序

Question

我正在制作 Web 应用程序。后端在Java，我用Spring。对于数据库，我使用 CouchDb，我想使用 Ektorp，但问题来了。当我添加 Ektorp 依赖项时它崩溃了。它可以编译，但是当我尝试运行时，我从下面得到错误。

Exception in thread "main" java.lang.IllegalArgumentException: Cannot instantiate interface org.springframework.context.ApplicationListener : org.springframework.boot.context.logging.ClasspathLoggingApplicationListener
    at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:450)
    at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:429)
    at org.springframework.boot.SpringApplication.getSpringFactoriesInstances(SpringApplication.java:420)
    at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:270)
    at org.springframework.boot.SpringApplication.<init>(SpringApplication.java:249)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
    at QEasyApplication.main(QEasyApplication.java:18)
Caused by: java.lang.NoClassDefFoundError: org/springframework/context/event/GenericApplicationListener
    at java.base/java.lang.ClassLoader.defineClass1(Native Method)
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:802)
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:700)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:623)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:398)
    at org.springframework.util.ClassUtils.forName(ClassUtils.java:275)
    at org.springframework.boot.SpringApplication.createSpringFactoriesInstances(SpringApplication.java:442)
    ... 7 more
Caused by: java.lang.ClassNotFoundException: org.springframework.context.event.GenericApplicationListener
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
    ... 20 more

Process finished with exit code 1

我尝试更改为不同版本的 Ektorp 或 spring 引导，但没有任何效果。下面是我的 Maven pom 文件。可能是什么问题呢？

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.1.3.RELEASE</version>
            <type>pom</type>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.ektorp</groupId>
            <artifactId>org.ektorp.spring</artifactId>
            <version>1.4.4</version>
        </dependency>
    </dependencies>
</project>

Answer 1

嗯，看来 org.springframework.context.event.GenericApplicationListener 不在您的类路径中。它位于 spring-context.

您声明，换句话说，您的 pom.xml 声明，有人应该为您提供 spring-boot-dependencies？我认为您混淆了 provided 和 import Maven scopes:

provided – "you expect the JDK or a container to provide the dependency at runtime"
import – "It indicates the dependency to be replaced with the effective list of dependencies in the specified POM's section."

所以有两种可能：

将spring-boot-dependencies的runtime范围切换为import
更好，让 Spring Boot 为您管理尽可能多的依赖项，并放置以下父 pom，以 利用Spring 的全部潜力 引导：

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
    </parent>

Ektorp 依赖项崩溃 Spring 启动应用程序

Ektorp dependency crashing Spring boot application

java

maven

spring-boot

ektorp