myeclipse(java compiler level does not match the version of the installed java project facet)

控制台problems报java compiler level does not match the version of the installed java project facet

1，window--perferences--java--compiler：设为1.7

2，workspace项目下面.settings文件夹下面org.eclipse.wst.common.project.facet.core.xml文件：修改<installed facet="java" version="1.7"/>即可