Referenced file contains errors (http://mybatis.org/dtd/mybatis-3-mapper.dtd). For more information,

用Eclipse做Maven项目时，XML文件第一行经常出现这种错误：

Referenced file contains errors (http://mybatis.org/dtd/mybatis-3-mapper.dtd). For more information, right click on the message in the Problems View
and select “Show Details…”
只需对以下代码进行修改

<!DOCTYPE mapper PUBLIC  "-//mybatis.org//DTD Mapper 3.0//EN"     
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

改成：

<!DOCTYPE mapper PUBLIC  "-//mybatis.org//DTD Mapper 3.0//EN"     
    "http://www.mybatis.org/dtd/mybatis-3-mapper.dtd">

问题就解决了。