用eclipse打包安卓项目失败

 !ENTRY com.android.ide.eclipse.adt 4 0 2017-06-27 09:38:11.264
!MESSAGE Export Wizard Error
!STACK 1
org.eclipse.core.runtime.CoreException: Failed to export application
    at com.android.ide.eclipse.adt.internal.project.ExportHelper.exportReleaseApk(ExportHelper.java:323)
    at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard.doExport(ExportWizard.java:313)
    at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard.access$0(ExportWizard.java:238)
    at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard$1.run(ExportWizard.java:223)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)
Caused by: java.lang.NullPointerException
    at com.android.ide.eclipse.adt.internal.build.BuildHelper.createWindowsProguardConfig(BuildHelper.java:652)
    at com.android.ide.eclipse.adt.internal.build.BuildHelper.runProguard(BuildHelper.java:571)
    at com.android.ide.eclipse.adt.internal.project.ExportHelper.exportReleaseApk(ExportHelper.java:259)
    ... 4 more
!SUBENTRY 1 com.android.ide.eclipse.adt 4 0 2017-06-27 09:38:11.264
!MESSAGE Failed to export application
!STACK 0
java.lang.NullPointerException
    at com.android.ide.eclipse.adt.internal.build.BuildHelper.createWindowsProguardConfig(BuildHelper.java:652)
    at com.android.ide.eclipse.adt.internal.build.BuildHelper.runProguard(BuildHelper.java:571)
    at com.android.ide.eclipse.adt.internal.project.ExportHelper.exportReleaseApk(ExportHelper.java:259)
    at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard.doExport(ExportWizard.java:313)
    at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard.access$0(ExportWizard.java:238)
    at com.android.ide.eclipse.adt.internal.wizards.export.ExportWizard$1.run(ExportWizard.java:223)
    at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121)

是我的混淆文件有问题么？

报的是空指针异常，应该是你的某个变量在使用的时候没有初始化或者只定义而没有赋值。看看代码，用断点调试查看一下，改过来再打包应该就没什么问题了。