我正在按照本教程https://spring.io/guides/gs/rest-service/来构建一个安静的应用程序.当我从Spring工具套件运行这个应用程序(作为spring boot应用程序运行)时,它会抛出错误：

Caused by: java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
        at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:155)
        at org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(SLF4JLogFactory.java:132)
        at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:273)
        at org.springframework.boot.SpringApplication.<clinit>(SpringApplication.java:190)
        at webapp.Application.main(Application.java:9)
        ... 6 more
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory

当我尝试使用项目initializr(https://start.spring.io/)时也会发生同样的错误.

我的pom.xml与教程完全一样：

<?xml version="1.0" encoding="UTF-8"?>

http://maven.apache.org/xsd/maven-4.0.0.xsd\”\u0026gt;
    4.0.0

<groupId>com.rondox.sb.restfulws</groupId>
<artifactId>wawa</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>wawa</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.2.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.jayway.jsonpath</groupId>
        <artifactId>json-path</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>


<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

<repositories>
    <repository>
        <id>spring-releases</id>
        <url>https://repo.spring.io/libs-release</url>
    </repository>
</repositories>
<pluginRepositories>
    <pluginRepository>
        <id>spring-releases</id>
        <url>https://repo.spring.io/libs-release</url>
    </pluginRepository>
</pluginRepositories>

我的依赖树：

[INFO] --- maven-dependency-plugin:2.10:tree (default-cli) @ wawa ---
[INFO] com.rondox.sb.restfulws:wawa:jar:0.0.1-SNAPSHOT
[INFO] +- org.springframework.boot:spring-boot-starter-web:jar:1.5.2.RELEASE:compile
[INFO] |  +- org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-autoconfigure:jar:1.5.2.RELEASE:compile
[INFO] |  |  +- org.springframework.boot:spring-boot-starter-logging:jar:1.5.2.RELEASE:compile
[INFO] |  |  |  +- ch.qos.logback:logback-classic:jar:1.1.11:compile
[INFO] |  |  |  |  \- ch.qos.logback:logback-core:jar:1.1.11:compile
[INFO] |  |  |  +- org.slf4j:jcl-over-slf4j:jar:1.7.24:compile
[INFO] |  |  |  +- org.slf4j:jul-to-slf4j:jar:1.7.24:compile
[INFO] |  |  |  \- org.slf4j:log4j-over-slf4j:jar:1.7.24:compile
[INFO] |  |  \- org.yaml:snakeyaml:jar:1.17:runtime
[INFO] |  +- org.springframework.boot:spring-boot-starter-tomcat:jar:1.5.2.RELEASE:compile
[INFO] |  |  +- org.apache.tomcat.embed:tomcat-embed-core:jar:8.5.11:compile
[INFO] |  |  +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.5.11:compile
[INFO] |  |  \- org.apache.tomcat.embed:tomcat-embed-websocket:jar:8.5.11:compile
[INFO] |  +- org.hibernate:hibernate-validator:jar:5.3.4.Final:compile
[INFO] |  |  +- javax.validation:validation-api:jar:1.1.0.Final:compile
[INFO] |  |  +- org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile
[INFO] |  |  \- com.fasterxml:classmate:jar:1.3.3:compile
[INFO] |  +- com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile
[INFO] |  |  +- com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile
[INFO] |  |  \- com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile
[INFO] |  +- org.springframework:spring-web:jar:4.3.7.RELEASE:compile
[INFO] |  |  +- org.springframework:spring-aop:jar:4.3.7.RELEASE:compile
[INFO] |  |  +- org.springframework:spring-beans:jar:4.3.7.RELEASE:compile
[INFO] |  |  \- org.springframework:spring-context:jar:4.3.7.RELEASE:compile
[INFO] |  \- org.springframework:spring-webmvc:jar:4.3.7.RELEASE:compile
[INFO] |     \- org.springframework:spring-expression:jar:4.3.7.RELEASE:compile
[INFO] +- org.springframework.boot:spring-boot-starter-test:jar:1.5.2.RELEASE:test
[INFO] |  +- org.springframework.boot:spring-boot-test:jar:1.5.2.RELEASE:test
[INFO] |  +- org.springframework.boot:spring-boot-test-autoconfigure:jar:1.5.2.RELEASE:test
[INFO] |  +- junit:junit:jar:4.12:test
[INFO] |  +- org.assertj:assertj-core:jar:2.6.0:test
[INFO] |  +- org.mockito:mockito-core:jar:1.10.19:test
[INFO] |  |  \- org.objenesis:objenesis:jar:2.1:test
[INFO] |  +- org.hamcrest:hamcrest-core:jar:1.3:test
[INFO] |  +- org.hamcrest:hamcrest-library:jar:1.3:test
[INFO] |  +- org.skyscreamer:jsonassert:jar:1.4.0:test
[INFO] |  |  \- com.vaadin.external.google:android-json:jar:0.0.20131108.vaadin1:test
[INFO] |  +- org.springframework:spring-core:jar:4.3.7.RELEASE:compile
[INFO] |  \- org.springframework:spring-test:jar:4.3.7.RELEASE:test
[INFO] \- com.jayway.jsonpath:json-path:jar:2.2.0:test
[INFO]    +- net.minidev:json-smart:jar:2.2.1:test
[INFO]    |  \- net.minidev:accessors-smart:jar:1.1:test
[INFO]    |     \- org.ow2.asm:asm:jar:5.0.3:test
[INFO]    \- org.slf4j:slf4j-api:jar:1.7.24:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.750 s
[INFO] Finished at: 2017-04-09T12:05:22+07:00

尝试过这个解决方案ClassNotFoundException: org.slf4j.LoggerFactory将最新的jar添加到类路径中,但它给出了另一个错误：

SLF4J: Class path contains multiple SLF4J bindings.

请抛出一些启示,我已经为这个问题奋斗了3天.

解决方法:

您的依赖项中有多个记录器,而slf4j不知道要使用哪个记录器.你应该检查Maven的依赖树来修复它.

logback-classic <-> log4j-over-slf4j <-> jboss-logging (?)

您可以排除Spring Boot Logging(默认情况下为Logback)并手动声明Log4j2：

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-log4j2</artifactId>
    </dependency>