将slf4j与log4j集成时出错

Question

为了在我的spring应用程序中登录，我正在集成sl4j之上的log4j，但是在启动tomcat时，我得到了一个错误，如下所示：

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/E:/apache-tomcat-8/apache-tomcat-8.0.3/webapp
s/ROOT/WEB-INF/lib/slf4j-jdk14-1.5.6.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/E:/apache-tomcat-8/apache-tomcat-8.0.3/webapps/ROOT/WEB-INF/lib/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/E:/apache-tomcat-8/apache-tomcat-8.0.3/webapps/ROOT/WEB-INF/lib/slf4j-nop-1.5.3.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.JDK14LoggerFactory]
SLF4J: The requested version 1.5.6 by your slf4j binding is not compatible with[1.6, 1.7]
SLF4J: See http://www.slf4j.org/codes.html#version_mismatch for further details.

我的pom.xml中的依赖项是：

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.7</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-all</artifactId>
            <version>1.9.5</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.1</version>
        </dependency>

        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache-core</artifactId>
            <version>2.5.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.3.2</version>
        </dependency>
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.1</version>
        </dependency>
        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.1</version>
        </dependency>
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-impl</artifactId>
            <version>2.2.7</version>
        </dependency>
        <dependency>
            <groupId>org.jvnet.jaxb2_commons</groupId>
            <artifactId>jaxb2-basics-runtime</artifactId>
            <version>0.6.0</version>
        </dependency>
        <dependency>
            <groupId>net.sf.opencsv</groupId>
            <artifactId>opencsv</artifactId>
            <version>2.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.9</version>
        </dependency>
        <dependency>
            <groupId>org.apache.axis</groupId>
            <artifactId>axis</artifactId>
            <version>1.4</version>
        </dependency>
        <dependency>
            <groupId>javax.xml</groupId>
            <artifactId>jaxrpc</artifactId>
            <version>1.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.axis2</groupId>
            <artifactId>axis2</artifactId>
            <version>1.6.2</version>
        </dependency>
        <dependency>
            <groupId>commons-discovery</groupId>
            <artifactId>commons-discovery</artifactId>
            <version>0.2</version>
        </dependency>

        <dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>
        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>1.0.0.GA</version>
        </dependency>
        <dependency>
            <groupId>javax.annotation</groupId>
            <artifactId>jsr250-api</artifactId>
            <version>1.0</version>
        </dependency>

        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.2.2</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>1.3.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.2.5</version>
        </dependency>

        <dependency>
            <groupId>javax.mail</groupId>
            <artifactId>mail</artifactId>
            <version>1.4</version>
        </dependency>
        <dependency>
            <groupId>org.quartz-scheduler</groupId>
            <artifactId>quartz</artifactId>
            <version>1.8.6</version>
        </dependency>

        <dependency>
            <groupId>commons-net</groupId>
            <artifactId>commons-net</artifactId>
            <version>3.3</version>
        </dependency>
        <dependency>
            <groupId>com.servletsuite</groupId>
            <artifactId>random</artifactId>
            <version>1.7</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tiles</groupId>
            <artifactId>tiles-extras</artifactId>
            <version>${tiles-version}</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>

        <!-- Spring starts here -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-oxm</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>

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

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${org.springframework.version}</version>
        </dependency>


        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${org.springframework.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>commons-logging</groupId>
                    <artifactId>commons-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--Spring Security -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-core</artifactId>
            <version>${org.springsecurity-version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
            <version>${org.springsecurity-version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-taglibs</artifactId>
            <!-- <version>3.2.0.RELEASE</version> -->
            <version>${org.springsecurity-version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
            <version>${org.springsecurity-version}</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.0-api</artifactId>
            <version>1.0.1.Final</version>
        </dependency>

        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
            <version>2.7.2</version>
        </dependency>
        <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
            <version>3.2.1</version>
        </dependency>
        <dependency>
            <groupId>commons-validator</groupId>
            <artifactId>commons-validator</artifactId>
            <version>1.4.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.9</version>
        </dependency>


        <!-- AspectJ -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjrt</artifactId>
            <version>${org.aspectj-version}</version>
        </dependency> 

        <!-- Logging -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${org.slf4j-version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${org.slf4j-version}</version>
            <scope>runtime</scope>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-1.2-api</artifactId>
            <version>2.0.2</version>
        </dependency>

        <!-- @Inject -->
        <dependency>
            <groupId>javax.inject</groupId>
            <artifactId>javax.inject</artifactId>
            <version>1</version>
        </dependency>

        <!--  Hibernate  -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>4.2.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate.common</groupId>
            <artifactId>hibernate-commons-annotations</artifactId>
            <version>4.0.1.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>${hibernate.version}</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.0-api</artifactId>
            <version>1.0.1.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>${hibernate.version}</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-ehcache</artifactId>
            <version>${hibernate.version}</version>
        </dependency>

        <!-- Spring Social -->
        <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-config</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-core</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-security</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-web</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency>

        <!-- Spring Social Facebook -->
        <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-facebook</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency>

        <!-- Spring Social Twitter -->
        <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-twitter</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency>

        <!-- Spring Social google -->
        <!-- <dependency>
            <groupId>org.springframework.social</groupId>
            <artifactId>spring-social-google</artifactId>
            <version>${org.springframework.social.version}</version>
        </dependency> -->

        <!-- Spring Data JPA -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jpa</artifactId>
            <version>2.0.8</version>
        </dependency>

    </dependencies>

很明显，类文件版本有一些不匹配之处，因为某些其他依赖项可能使用其他版本的log4j，而我需要在pom中排除这些版本，但无法找到合适的版本，请帮助。

Answer 1

Slf4j正在告诉您多个问题：

• 您正在使用多个版本，这些版本可能互不兼容。
• 有多个StaticLoggerBinder实现可用。

您的依赖项可能包括其他slf4j依赖项，要找到它们，可以使用mvn依赖项:tree，并将它们排除在pom.xml中。

此外，您应该选择要在应用程序中使用的底层记录器。http://www.slf4j.org/images/concrete-bindings.png

现在，slf4j使用JDK14LoggerFactory，如果您在tomcat中运行应用程序，我认为这是一个很好的决定。

你最终应该做什么？

将slf4j-log4j12.jar和slf4j-nop-1.5.3.jar从类路径(WEB/lib)中删除，方法是排除pom.xml中的隐式导入，但要显式地添加slf4jjdk14.jar。此外，我还会考虑删除所有log4j-jar，并将它们替换为log4joverslf4j.jar。

log4j -overslf4j.jar正在使用slf4j的后端，但是实现了log4j接口，并且完全兼容API。

Answer 2

pom包括以下依赖项：

    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-1.2-api</artifactId><!-- bridge between log4j-1.2 and log4j2-->
        <version>2.0.2</version>
    </dependency>

这是一个桥接jar，用于在代码使用log4j-1.2API的应用程序中使用log4j2。仅使用桥jar是不够的:如果您想使用log4j2，还需要添加log4j-api和log4j核心依赖项。(请参阅要使用的log4j2 哪个罐子上的常见问题。)

此外，如果您(或您使用的任何库)使用slf4j，那么还可以添加log4j-slf4j-impl依赖项。类似地，log4j-jcl依赖项支持公用日志记录。

因此，在下面添加依赖项：

    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-api</artifactId>
        <version>2.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-core</artifactId><!-- log4j2 implementation-->
        <version>2.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-jcl</artifactId><!-- bridge to commons-logging-->
        <version>2.0.2</version>
    </dependency>
    <dependency>
        <groupId>org.apache.logging.log4j</groupId>
        <artifactId>log4j-slf4j-impl</artifactId><!-- bridge to slf4j-->
        <version>2.0.2</version>
    </dependency>

顺便说一句，log4j2的最新版本是2.2，所以您可能希望使用2.2而不是2.0.2。

另外，删除此依赖项(它转发给log4j-1.2实现)：

    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>${org.slf4j-version}</version>
        <scope>runtime</scope>
        <exclusions>
            <exclusion>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
            </exclusion>
        </exclusions>
    </dependency>