mybatis mapper配置错误

Question

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

select * from user where id = #{id}

以上是我的mapper的xml配置文件
然后测试的时候报错 报错信息为：
org.apache.ibatis.exceptions.PersistenceException:

Error building SqlSession.

The error may exist in sqlmap/User.xml

Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error creating document instance. Cause: org.xml.sax.SAXParseException; lineNumber: 7; columnNumber: 26; 必须为元素类型 "mapper" 声明属性 "namespace"。

at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:26)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:82)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:66)
at com.nullException.mybatis.first.MybatisFirst.init(MybatisFirst.java:22)
at com.nullException.mybatis.first.Test.main(Test.java:8)

Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error creating document instance. Cause: org.xml.sax.SAXParseException; lineNumber: 7; columnNumber: 26; 必须为元素类型 "mapper" 声明属性 "namespace"。
at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:109)
at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:92)
at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:80)
... 3 more

初学者，问题可能很白痴，有了解的大神帮忙看一下哈

Answer 1

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.eumji.zblog.mapper.ArticleMapper">

namespace="这是你对应的mapper的全路径"