环境：gradle+Android studio
问题：运行工程时报如下错误信息，

Error:Execution failed for task ':app:transformResourcesWithMergeJavaResForDebug'.
> com.android.build.api.transform.TransformException: com.android.builder.packaging.DuplicateFileException: Duplicate files copied in APK META-INF/LICENSE
    File1: D:\Program Files\apache-maven\repo\org\codehaus\jackson\jackson-mapper-asl\1.9.7\jackson-mapper-asl-1.9.7.jar
    File2: D:\Program Files\apache-maven\repo\org\codehaus\jackson\jackson-core-asl\1.9.7\jackson-core-asl-1.9.7.jar

解决方法：
1、找到相应的.jar文件，用WinRAR(解压工具）打开。打开META-INF文件夹。

QQ截图20170218184147.png

将这个目录下的子文件名添，按步骤2进行添加。

2、在Model的build.gradle中添加一下内容：

packagingOptions {
        exclude 'LICENSE.txt'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/ASL2.0'
    }

按照stackoverflow上回答的问题原因是：

Almost all OS licence include the obligation to "include a copy of the licence" into your project.   
So this means, that you have to include a copy of all OS licences you use into you projects.   
By "excluding" them in gradle, you violate the licences. 

参考：http://blog.csdn.net/ioiol/article/details/50491801