Android studio运行时，出现org.gradle.process.internal.ExecException异常

Error:Execution failed for task ‘:app:dexDebug’.
com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process ‘command ‘E:\jdk8\bin\java.exe” finished with non-zero exit value 2
这是由于未正确导入插件（比如v4,v7等包）造成的。重新导入一下就好了。