maven jar包冲突小记

本地调试报错：

 

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/E:/repository/org/slf4j/slf4j-nop/1.6.1/slf4j-nop-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/E:/repository/org/slf4j/slf4j-log4j12/1.7.12/slf4j-log4j12-1.7.12.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.helpers.NOPLoggerFactory]

分析过程(先后执行了)：

        mvn dependency:list
        mvn dependency:tree -Dverbose -Dincludes=org.slf4j

执行后输出为：

 

[INFO] +- b:c:jar:2.0.0-SNAPSHOT:compile
[INFO] |  +- org.slf4j:slf4j-api:jar:1.7.12:compile
[INFO] |  \- com.google.code:fqueue:jar:0.0.2-release:compile
[INFO] |     +- commons-lang:commons-lang:jar:2.5:compile
[INFO] |     +- commons-logging:commons-logging:jar:1.1.1:compile
[INFO] |     +- org.slf4j:slf4j-nop:jar:1.6.1:compile
[INFO] |     \- org.jboss.netty:netty:jar:3.2.4.Final:compile

[INFO] +- b:d:jar:2.0.0-SNAPSHOT:compile
[INFO] |  +- org.slf4j:slf4j-log4j12:jar:1.7.12:runtime
[INFO] |  +- log4j:log4j:jar:1.2.16:compile
[INFO] |  \- commons-codec:commons-codec:jar:1.4:compile

就是因为a包依赖了b.c和b.d，这两者中的slf4j-nop和slf4j-log4j12冲突了。

 

解决办法，通过在dependency中采用exclusions来选择性的排除依赖就ok了

 

              <dependency>
    <groupId>b</groupId>
    <artifactId>c</artifactId>
    <version>2.0.0-SNAPSHOT</version>
      <exclusions>
        <exclusion>  <!-- declare the exclusion here -->
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-nop</artifactId>
        </exclusion>
      </exclusions>
</dependency>