基本的bash编程(Basic bash programming)

 我发现任何时候更新项目的POM都有助于重新运行m2eclipse，否则它不会看到新的外部依赖关系。 
 
 如果您在添加新的依赖关系（JPA + Hibernate或其他任何）到您的POM之后还没有尝试运行此操作，请尝试一下，看看它是否有效。 
 
mvn clean install eclipse:clean eclipse:eclipse eclipse:m2eclipse
 
 请注意，执行此操作后，您可能需要刷新您的Eclipse项目以使更改生效。 
 
 它可能不需要所有这些论据都起作用，但我只是为了确定而在一点上添加了它们。 您可以调整参数列表以使其适用于您。 
 
 这样做可能会让您的项目中的某些Eclipse偏好失效，因此希望您拥有在POM中重建项目所需的一切。 例如，我在其中一个POM中添加了一些额外的东西，以确保当使用maven重新构建eclipse项目时，springnature和springbuilder将添加到我的eclipse项目中。 
 
<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-eclipse-plugin</artifactId>
      <configuration>
        <additionalProjectnatures>
          <projectnature>
            org.springframework.ide.eclipse.core.springnature
          </projectnature>
          <projectnature>
            org.eclipse.wst.common.project.facet.core.nature
          </projectnature>
          <projectnature>
            org.eclipse.wst.common.modulecore.ModuleCoreNature
          </projectnature>
          <projectnature>
            org.eclipse.jem.workbench.JavaEMFNature
          </projectnature>
        </additionalProjectnatures>
        <additionalBuildcommands>
          <buildcommand>
            org.eclipse.wst.common.project.facet.core.builder
          </buildcommand>
          <buildcommand>
            org.eclipse.wst.validation.validationbuilder
          </buildcommand>
          <buildcommand>
            org.springframework.ide.eclipse.core.springbuilder
          </buildcommand>
        </additionalBuildcommands>
        <wtpversion>1.5</wtpversion>
      </configuration>
    </plugin>
  </plugins>
</build>
 
 最后一点被添加为警告！ 如果他们没有准备好运行eclipse：*命令的后果，会痛恨某人采用正在运行的Eclipse项目并销毁一堆配置。 

I have found that any time you update a project's POM it helps to rerun m2eclipse or it will not see the new external dependencies.
 
If you have not tried to run this since you added your new dependencies ( JPA + Hibernate or whatever ) to your POM then give it a shot and see if it works.
 
mvn clean install eclipse:clean eclipse:eclipse eclipse:m2eclipse
 
Please note that after you execute this, you will probably need to refresh your Eclipse projects for the changes to take effect.
 
It might not require all of these arguments to work, but I sort of added them all at one point just to make certain. You can tweak the list of arguments to get it to the point that it works for you.
 
Doing this may blow away some of your Eclipse preferences for your project, so hopefully you have everything needed to rebuild your project already in your POM. For instance, I have a bunch of extra things in one of my POMs to ensure that things like springnature and springbuilder are added to my eclipse project when maven is used to rebuild the eclipse project.
 
<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-eclipse-plugin</artifactId>
      <configuration>
        <additionalProjectnatures>
          <projectnature>
            org.springframework.ide.eclipse.core.springnature
          </projectnature>
          <projectnature>
            org.eclipse.wst.common.project.facet.core.nature
          </projectnature>
          <projectnature>
            org.eclipse.wst.common.modulecore.ModuleCoreNature
          </projectnature>
          <projectnature>
            org.eclipse.jem.workbench.JavaEMFNature
          </projectnature>
        </additionalProjectnatures>
        <additionalBuildcommands>
          <buildcommand>
            org.eclipse.wst.common.project.facet.core.builder
          </buildcommand>
          <buildcommand>
            org.eclipse.wst.validation.validationbuilder
          </buildcommand>
          <buildcommand>
            org.springframework.ide.eclipse.core.springbuilder
          </buildcommand>
        </additionalBuildcommands>
        <wtpversion>1.5</wtpversion>
      </configuration>
    </plugin>
  </plugins>
</build>
 
This last bit was added as a warning! Would hate for someone to take a working Eclipse project and destroy a bunch of the configuration if they were not already prepared for the consequences of running the eclipse:* commands.