(NetBeans7.1.1）求大神们帮帮忙，谢谢了...

[yfj1314]

弄了个关机程序，编译，运行都没问题，然后直接点击清理并生成主项目（打包成jar）,双击jar打不开，发现MF文件为
Manifest-Version: 1.0
X-COMMENT: Main-Class will be added automatically by build
然后删掉再重新来过，这次编译后把MF文件修改为
Manifest-Version: 1.0
Main-Class：guanji
点击清理并生成主项目时提示：E:\guanji\nbproject\build-impl.xml:678: Existing manifest E:\guanji\build\null749530493 is invalid.