在安装后，出现下列警告：

The Maven Integration requires that Eclipse be running in a JDK, because a number of Maven core plugins are using jars from the JDK.

Please make sure the -vm option in eclipse.ini is pointing to a JDK and verify that Installed JRE’s are also using JDK installs.

解决：

（1）设置系统安装的JDK目录set your JDK as a default Java environment in eclipse (default installed JRE)

Open eclipse. Click on ‘Window’ -> ‘Preferences’ -> ‘Java’ -> ‘Installed JREs’.

If you can’t find any JDK on the list -> click ‘Add’ -> ‘Standard VM’ -> set all paths and click ‘Finish’.

After that – check this JDK on the list of installed JREs and click ‘OK’.

（2）增加JDK路径到eclipse.ini文件中add path to your SDK in eclipse.ini

open ‘eclipse.ini’ and add there: -vm path_to_javaw_on_your_machine，so in my example it will be (jdk1.6.0_17 on Windows):-vm
D:\\Java\jdk1.6.0_13\jre\bin\javaw
不能有空格，否则要用~1代替，如： ‘Program Files’ is ‘Progra~1′. Notice 1: Do not use paths with spaces! Replace all dir names with spaces to their shortcuts. For example: ‘Program Files’ is ‘Progra~1′.
要分为2行写。Notice 2: ‘-vm’ is in the first line, path is in the second line

your ‘eclipse.ini’ looks like this:

-startup
plugins/org.eclipse.equinox.launcher_1.0.201.R35x_v20090715.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.0.200.v20090519
-showsplash
org.eclipse.platform
--launcher.XXMaxPermSize
256m
-vm
D:\Java\jdk1.6.0_13\jre\bin\javaw
-vmargs
-Xms40m
-Xmx256m
-vm要在-vmargs前面。Notice : ‘-vm’ must be  "-vmargs" above

重启eclipse。Restart eclipse and everything should be fine.

在maven2中使用tomcat plugin启动web应用，在pom.xml中加入以下配置信息：

      

<project>
...
<build>
<!-- To define the plugin version in your parent POM -->
<pluginManagement>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>tomcat-maven-plugin</artifactId>
<version>1.0-beta-1</version>
</plugin>
...
</plugins>
</pluginManagement>
<!-- To use the plugin goals in your POM or parent POM -->
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>tomcat-maven-plugin</artifactId>
<version>1.0-beta-1</version>
</plugin>
...
</plugins>
</build>
...
</project>

运行mvn tomcat:run后，tomcat报

java.lang.ClassCastException: common.filter.CacheFilter cannot be cast to javax.servlet.Servlet 

【分析原因】 
由于CacheFilter实现了javax.servlet.Filter接口，Filter是在servlet-api.jar里，因此pom中有

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.4</version>
        </dependency>

【解决办法】
servlet-api加入<scope>provided</scope>，如下：

<dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.4</version>
            <scope>provided</scope>
        </dependency>

这样修改后，servlet-api.jar就不会在运行tomcat时被import进去了，不会与tomcat自带的servlet-api有冲突

【避免此类问题的建议】
注意pom.xml中关于包的scope的定义，解决此类包冲突产生的问题