Mybatis Learning-3

1. Designing the DAO Interface

Public interface Userdao {

public boolean addUser (user user);

}

Public interface CategoryDao {

public boolean addcategory (category category);

Public Category Getcategorybyid (int id);

Public list<category> Getallcategorys ();

}

Public interface Articledao {

public Boolean addarticle (article article);

Public article Getarticlebyid (int id);

Public list<article> getallarticles ();

Public list<article> getarticelsbycategory (int categoryId);

Public list<article> Getarticlesbytitle (String title);

}

2. Implement the interface

public class Userdaoimpl extends basedao<user> implements Userdao {

@Override

public boolean addUser (user user) {

try {

Super.add (user);

return true;

} catch (Exception e) {

E.printstacktrace ();

return false;

}

}

}

-------The mapping file for this configuration (don't forget to add an alias "Mybatis.cfg.xml" to the entity class in the core configuration file)

<typeAliases>

<typealias alias= "User" type= "Cn.smartapp.blogs.pojo.User"/>

<typealias alias= "Category" type= "Cn.smartapp.blogs.pojo.Category"/>

<typealias alias= "article" type= "Cn.smartapp.blogs.pojo.Article"/>

</typeAliases>

Mapping file for User entity class

<?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= "Cn.smartapp.blogs.pojo.User" >

<insert id= "Insertpojo" parametertype= "User" usegeneratedkeys= "true" >

Insert into Blog_user (user_name,user_pass,nick_name) VALUES (#{username},#{password},#{nickname})

</insert>

</mapper>

Do not forget to add mappings to the core configuration file after the mapping file has been written.

<mappers>

<mapper resource= "Cn/smartapp/blogs/pojo/user.xml"/>

<mapper resource= "Cn/smartapp/blogs/pojo/category.xml"/>

<mapper resource= "Cn/smartapp/blogs/pojo/article.xml"/>

</mappers>

2. Do a test that adds a user

public class Userdaoaddtest

@Test

public void Test () {

Userdao Userdao = new Userdaoimpl ();

User user = new user ();

User.setusername ("mingming");

User.setpassword ("123123");

User.setnickname ("Ming");

Boolean doflag = userdao.adduser (user);

Assert.asserttrue (Doflag);

}

}

3. Implement article one-to-many bidirectional association (user,category)

(1) many to one association, because article is from the table, so article is more of a party, from this side associated

-"Implement Articledao (the code is slightly, as before)

<?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= "Cn.smartapp.blogs.pojo.Article" >

<resultmap type= "article" id= "Articleresult" >

<id column= "aid" property= "id"/>

<result column= "Art_title" property= "title"/>

<result column= "art_content" property= "content"/>

<result column= "Art_pubtime" property= "Pubtime" javatype= "Java.util.Date"/>

<association property= "User" foreigncolumn= "pub_user_id" >

<id column= "UID" property= "id"/>

<result column= "user_name" property= "UserName"/>

<result column= "User_pass" property= "password"/>

<result column= "Nick_name" property= "nickname"/>

</association>

<association property= "Category" foreigncolumn= "cate_id" >

<id column= "CID" property= "id"/>

<result column= "Cate_name" property= "Catename"/>

</association>

</resultMap>

<insert id= "Insertpojo" parametertype= "article" usegeneratedkeys= "true" >

Insert into Blog_article (art_title,art_content,art_pubtime,pub_user_id,cate_id)

VALUES (#{title},#{content},#{pubtime},#{user.id}), #{category.id})

</insert>

<select id= "Selectbyid" resultmap= "Articleresult" parametertype= "int" >

Select

Ta.id as aid,

Ta.art_title,

Ta.art_content,

Ta.art_pubtime,

TA.PUB_USER_ID,

TA.CATE_ID,

Tu.id as UID,

Tu.user_name,

Tu.user_pass,

Tu.nick_name,

Tc.id as CID,

Tc.cate_name

From Blog_user as Tu inner joins blog_article as TA on tu.id=ta.pub_user_id

INNER JOIN Blog_category as TC on tc.id=ta.cate_id where Ta.id=#{id}

</select>

<select id= "SelectAll" resultmap= "Articleresult" >

Select

Ta.id as aid,

Ta.art_title,

Ta.art_content,

Ta.art_pubtime,

TA.PUB_USER_ID,

TA.CATE_ID,

Tu.id as UID,

Tu.user_name,

Tu.user_pass,

Tu.nick_name,

Tc.id as CID,

Tc.cate_name

From Blog_user as Tu inner joins blog_article as TA on tu.id=ta.pub_user_id

INNER JOIN Blog_category as TC on TC.ID=TA.CATE_ID

</select>

<select id= "Selectbycategory" resultmap= "Articleresult" >

Select

Ta.id as aid,

Ta.art_title,

Ta.art_content,

Ta.art_pubtime,

TA.PUB_USER_ID,

TA.CATE_ID,

Tu.id as UID,

Tu.user_name,

Tu.user_pass,

Tu.nick_name,

Tc.id as CID,

Tc.cate_name

From Blog_user as Tu inner joins blog_article as TA on tu.id=ta.pub_user_id

INNER JOIN Blog_category as TC on tc.id=ta.cate_id where Tc.id=#{cid}

</select>

<select id= "Selectbytitle" resultmap= "Articleresult" >

Select

Ta.id as aid,

Ta.art_title,

Ta.art_content,

Ta.art_pubtime,

TA.PUB_USER_ID,

TA.CATE_ID,

Tu.id as UID,

Tu.user_name,

Tu.user_pass,

Tu.nick_name,

Tc.id as CID,

Tc.cate_name

From Blog_user as Tu inner joins blog_article as TA on tu.id=ta.pub_user_id

INNER JOIN Blog_category as TC on tc.id=ta.cate_id where ta.title like #{title}

</select>

</mapper>

Mybatis Learning-3