添加dtd文件

Window => Preferences => XML XML Catalog => add

例如mybatis-config.xml文件的文件头如下：

<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">

在Eclipse中应该设置：

添加dtd文件

将class文件输出到指定文件夹
Project=>Properties=>Java Build Path=>Source=>Browser...

修改class文件输出路径

这样做的用途：
在eclipse中默认输出的class实在bin目录下的，但是在默认情况下，tomcat会在WEB-INF/classes这个目录下查找class文件，而不是在bin目录下查找。通过更改class文件的输出路径到WEB-INF/classes这样的操作，我们可以把web应用方便地部署到tomcat。

显示空包或web/WEB-INF下的classes文件夹
Navigate=>Show In=>Navigator <=> Alt+Shift+W
看看效果，呦吼~

Package Explorer.PNG

Navigator.PNG

原因：
工程项目的个目录下面没有.project和.classpath这两个文件

解决：

1. 建一个项目，这个项目的项目名要import的项目名称一样；
2. 新建的项目目录里面有上述的两个文件，把上述两个文件拷到你要import的项目目录下面；
3. 删除之前建的那个项目，然后再重新import。

修改Eclipse的编码格式
Window=>Preferences=>Work Space

GBK-UTF-8.PNG

导入Maven项目：The declared package "com.myself" does not match the expected package "main.java.com.myself"

Set my-project/src/main/java as the source folder (Project => Properties => Java Build Path => Project => Add Folder). Remove the old source folder.

Restart eclipse if necessary.

Simply put, Eclipse thinks that your project begins at my-project/src. Therefore, it expects all packages to descend from there, starting with main.java.
问题解决来自：stackoverflow
The tomcat server configuration at /sever/tomcat v7.0 localhost-config is missing
原因：做项目时用的tomcat的版本/路径和现在用 不一样，tomcat版本或者路径问题。
解决：更改项目的tomcat或者路径版本方法。
项目右击=>run as=>run on server=> manually define a new server

No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?

1. On your Eclipse IDE, go into Window > Preferences > Java > Installed JREs > and check your installed JREs. You should have an entry with a JDK there.
2. Select the Execution Env as show below. Click OK
3. ThenRight-Clickon your Project -> Maven -> Update Project

Additionally, you may have to change Maven JRE which is as follows. Goto Run -> Run Configurations, selecting the Maven Build I was running (from the left panel). Then, I clicked the JRE tab and selected the option Workspace default JRE

重命名
alt+shift+R

Insert
插入变改写：Inert键可以打出一个的时候删掉一个字。
另外：终端下
Ctrl+Insert是复制
Shift+Insert是粘贴
Ctrl+C 是终止正在运行的进程