为什么eclipse尝试编译不在我的构建路径中的文件？

I have a rather large project which contains a number of third-party dependencies which are linked via svn:externals. These include tomcat and blazeDS, which are packaged by our installer via ant. The problem is that these projects contain dozens of sample JSP pages, and eclipse chokes on them when trying to build the project, producing hundreds of errors.I have a rather large project which contains a