一般是因爲本身的 工程 建得不對, 沒有聲明爲 JAVA 或 PHP 類型工程。php
例如, PHP 工程的 .project 文件中的內容若是以下, F3 應該就能夠起做用了。java
<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
<name>projectName</name>
<comment></comment>
<projects>
</projects>
<buildSpec>
<buildCommand>
<name>org.eclipse.dltk.core.scriptbuilder</name>
<arguments>
</arguments>
</buildCommand>
<buildCommand>
<name>org.eclipse.php.core.PhpIncrementalProjectBuilder</name>
<arguments>
</arguments>
</buildCommand>
<buildCommand>
<name>org.eclipse.wst.validation.validationbuilder</name>
<arguments>
</arguments>
</buildCommand>
</buildSpec>
<natures>
<nature>org.eclipse.php.core.PHPNature</nature>
</natures>
</projectDescription>spring
又例如,JAVA Spring Tomcat 項目的 .project 文件中的內容以下:tomcat
<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
<name>projectName</name>
<comment></comment>
<projects>
</projects>
<buildSpec>
<buildCommand>
<name>org.eclipse.jdt.core.javabuilder</name>
<arguments>
</arguments>
</buildCommand>
<buildCommand>
<name>org.springframework.ide.eclipse.core.springbuilder</name>
<arguments>
</arguments>
</buildCommand>
</buildSpec>
<natures>
<nature>org.springframework.ide.eclipse.core.springnature</nature>
<nature>org.eclipse.jdt.core.javanature</nature>
<nature>com.sysdeo.eclipse.tomcat.tomcatnature</nature>
</natures>
</projectDescription>eclipse