Spring - 避免混合版本

Question

在运行我的 Spring Boot 应用程序时，我收到以下错误：

尝试调用方法org.springframework.web.reactive.function.client.WebClient.builder()Lorg/springframework/web/reactive/function/client/WebClient$Builder; but it does not exist. Its class, org.springframework.web.reactive.function.client.WebClient, is available from the following locations:

jar:file:/C:/Users/Wicia/.m2/repository/org/springframework/spring-web-reactive/5.0.0.M4/spring-web-reactive-5.0.0.M4.jar!/org/springframework/web/reactive/function/client/WebClient.class

它是从以下位置加载的：

file:/C:/Users/Wicia/.m2/repository/org/springframework/spring-web-reactive/5.0.0.M4/spring-web-reactive-5.0.0.M4.jar

行动：

Correct the classpath of your application so that it contains a single, compatible version of org.springframework.web.reactive.function.client.WebClient

---

我发现了一条线索，我应该为所有工件指定通用的 spring 版本（而不是混合它），但是该怎么做呢？

这是我的 pom.xml：

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.0.0.M4</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>5.0.1.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web-reactive</artifactId>
    <version>5.0.0.M4</version>
</dependency>
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-cassandra</artifactId>
    <version>2.1.0.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.0.5.RELEASE</version>
</dependency>

Answer 1

如果依赖项由 Spring 管理，请不要在 pom.xml 中定义依赖项版本。而是使用 spring-boot-starter-parent 作为父级。

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web-reactive</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-cassandra</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
<dependencies>

Spring-boot-parent 为几乎所有流行的依赖项定义了版本，因此默认情况下您可以跳过定义版本。仅当您收到 POM 错误时才定义它（意味着您添加了一个不受 Spring Boot 管理的唯一依赖项）