resultMap中两张表id字段相同，数据查询异常解决

最近，在学习MyBatis 关联数据查询时，遇到了问题。
User表在本例子中存储文章作者的相关信息。User表的详细设计如下：



Article表存储了文章的相关内容。Article表的详细设计如下：



对应的实体类：
package com.test.mybatis.pojo;

public class User {
private int id;
private String name;
private int age;
private String address;

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public String getAddress() {
return address;
}

public void setAddress(String address) {
this.address = address;
}

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

}

package com.test.mybatis.pojo;

public class Article {
private int id;
private User user;
private String title;
private String content;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public User getUser() {
return user;
}

public void setUser(User user) {
this.user = user;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getContent() {
return content;
}

public void setContent(String content) {
this.content = content;
}

}

需要注意的是，Article持有的是User的引用，而不是userid。
MyBatis配置如下：
<resultMap type="Article" id="userArticleList">
<id column="id" property="id"/>
<result column="title" property="title"/>
<result column="content" property="content"/>
<association property="user" javaType="User">
<id column="id" property="id" />
<result column="name" property="name"/>
<result column="age" property="age"/>
<result column="address" property="address"/>
</association>
</resultMap>
<select id="queryArticlesByUser" parameterType="int" resultMap="userArticleList">
select user.id, user.name, user.age, user.address, article.id, article.title, article.content
from user, article where user.id = article.userid and user.id = #{id}
</select>在Test中，传递User的id为1，只能查询到一条数据，而直接在命令行执行SQL语句，却能够查询到四条数据。





两张表中的id字段名相同，导致无法正常映射。解决办法是为列起别名。
<resultMap type="Article" id="userArticleList">
<id column="id" property="id"/>
<result column="title" property="title"/>
<result column="content" property="content"/>
<association property="user" javaType="User">
<!-- 别名uid -->
<id column="uid" property="id" />
<result column="name" property="name"/>
<result column="age" property="age"/>
<result column="address" property="address"/>
</association>
</resultMap>
<select id="queryArticlesByUser" parameterType="int" resultMap="userArticleList">
select user.id uid, user.name, user.age, user.address, article.id, article.title, article.content
from user, article where user.id = article.userid and user.id = #{id}
</select>这样便能正确查到四条数据。