MyBatis usage (Configuration and annotation usage)

MyBatis is a persistent layer framework usage (xml-based configuration) 1. Add Dependencies (Maven)

<!--database related, MySQL, mybatis--> <!--JDBC Connection--> <dependency> <groupid>mysql</groupid > <artifactId>mysql-connector-java</artifactId> <version>5.1.37</version> & lt;/dependency> <!--spring-mybatis--> <dependency> <groupid>org.mybatis</groupid > <artifactId>mybatis-spring</artifactId> <version>${mybatis-spring-version}</vers Ion> </dependency> <!--mybatis--> <dependency> <groupid>org.mybatis</gro
    Upid> <artifactId>mybatis</artifactId> <version>${mybatis-version}</version> </dependency> <!--reflection Generation entity class--> <dependency> <groupid>org.mybatis.generator</gr 
    Oupid> <artifactId>mybatis-generator-core</artifactId> <version>1.3.2</version> </dependency> 

2. Establish database, table

CREATE DATABASE testdatabase;
Use Testdatabase;
CREATE TABLE User (id int PRIMARY KEY auto_increment, userName VARCHAR not NULL, userage INT not NULL);

INSERT into User (UserName, userage) VALUES (' xiaoxin ',);
INSERT into User (UserName, userage) VALUES (' xiaoming ', 22);

3. Entity classes for tables

Package com.xiaoxin.demo.dto;

public class User {
	private int id;
    Private String userName;
    private int userage;
	public int getId () {return
		ID;
	}
	public void setId (int id) {
		this.id = ID;
	}
	Public String GetUserName () {return
		userName;
	}

	public void Setusername (String userName) {
		this.username = userName;
	}
	public int getuserage () {return
		userage;
	}
	public void setuserage (int userage) {
		this.userage = userage;
	}
	@Override public
	String toString () {return
		"User [id=" + ID + ", username=" + UserName + ", userage=" + userage + "]";
	}
}

4. Add a MyBatis profile

<?xml version= "1.0" encoding= "UTF-8"?> <!
DOCTYPE configuration Public "-//mybatis.org//dtd Config 3.0//en" "Http://mybatis.org/dtd/mybatis-3-config.dtd" > 
    <configuration> <typeAliases> <typealias alias= "User" type= "Com.xiaoxin.demo.dto.User"/> </typeAliases> <!--database environment configuration--> <environments default= "Development" > <environment id= "Development" > <!--JDBC Management--> <transactionmanager type= "jdbc"/> <!--what connection pool to use--&G
            T <datasource type= "Pooled" > <!--JDBC driver--> <property name= "Driver" value= . jdbc. Driver "/> <!--database name url--> <property name=" url "value=" jdbc:mysql://127.0.0.1:3306/tes Tdatabase "/> <!--database user--> <property name=" username "value=" root "/> &L t;!
     --Database user password--> <property name= "password" value= ""/>       </dataSource> </environment> </environments> <!--register User.xml to MyBatis's profile, Us Er.xml Configure--> <mappers> <mapper resource= "Com/xiaoxin/demo/dto/user.xml"/> </mappers&gt
; </configuration>

5. Define the mapping file to manipulate the user table, and step fourth has been registered in the MyBatis configuration file.

<?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" >
<!--Define SQL mapping files that manipulate the user table Usermapper.xml  -->
<mapper namespace= "Com.xiaoxin.demo.dto" >
    <select id= "Selectuserbyid" parametertype= "int" resulttype= "user" >
        select * from ' user ' where id = #{id}
    & Lt;/select>
</mapper>

6. Test

Package com.xiaoxin.demo.dto;

Import Java.io.Reader;

Import org.apache.ibatis.io.Resources;
Import org.apache.ibatis.session.SqlSession;
Import org.apache.ibatis.session.SqlSessionFactory;
Import Org.apache.ibatis.session.SqlSessionFactoryBuilder;
Import Org.junit.Test;

public class TestUser {
	@Test public
	void TestUser () throws exception{
		 sqlsessionfactory sqlsessionfactory ;
	     Reader reader; 
	     String resource = "Spring/configuration.xml";
	     Load a stream
	     reader= resources.getresourceasreader (Resource);
	     Generate Sqlsessionfactory factory
	     sqlsessionfactory = new Sqlsessionfactorybuilder (). build (reader);
	     sqlsession session = Sqlsessionfactory.opensession ();
	     User user = (user) Session.selectone ("Com.xiaoxin.demo.dto.selectUserByID", 1);
	     System.out.print (User.tostring ());
	    Session.close ();
		
	}
	

Connect database successfully query to data

CRUD Operations Rollup

<?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" >
<!--Define SQL mapping files that manipulate the users table Usermapper.xml  -->
<mapper namespace= "Com.xiaoxin.demo.dto" >
    <!--query  -->
     <select id= "Selectuserall" parametertype= "int" resulttype= "User" >
        SELECT * From user
    </select>
    <!--insert  -->
    <insert id= "Insertuser parametertype=" Com.xiaoxin.demo.dto.User ">
    		insert INTO User (username,userage) VALUES (#{username},#{userage});
    </insert>
	<!--update  -->
    <update id= "UpdateUser" parametertype= " Com.xiaoxin.demo.dto.User ">
    		update User set Userage=#{userage},username=#{username} where Id=#{id}
    </update>
    <!--delete  -->
    <delete id= "deleteuser" parametertype= "int" >
    	Delete From user where Id=#{id}
    </delete>
    
</mapper>

Test

Package com.xiaoxin.demo.dto;
Import Java.io.Reader;

Import java.util.List;
Import org.apache.ibatis.io.Resources;
Import org.apache.ibatis.session.SqlSession;
Import Org.apache.ibatis.session.SqlSessionFactory;
Import Org.apache.ibatis.session.SqlSessionFactoryBuilder;

Import Org.junit.Test;
	     public class TestUser {@Test the public void TestUser () throws exception{sqlsessionfactory sqlsessionfactory; 
	     Reader reader;
	     String resource = "Spring/configuration.xml";
	     Load a stream reader= Resources.getresourceasreader (Resource);
	     Generate Sqlsessionfactory Factory sqlsessionfactory = new Sqlsessionfactorybuilder (). build (reader);
	     sqlsession session = Sqlsessionfactory.opensession ();
Insert//User user1 = new User ();
User1.setusername ("Xiaohong");
User1.setuserage (20);
Session.insert ("Com.xiaoxin.demo.dto.insertUser", user1);
Session.commit () Be sure to do otherwise there is no information in the database ....
	    Session.commit (); Update//Put Xiaohong's nameChange to Xiaohong101 age to Xiaohong ID is the//User User3 = new User ();
User3.setusername ("Xiaohong101");
User3.setuserage (44);
User3.setid (16);
Session.update ("Com.xiaoxin.demo.dto.updateUser", User3);
	     
	    Session.commit ();
	     Delete Session.delete ("Com.xiaoxin.demo.dto.deleteUser", 16);
	     Session.commit ();
	     Query database All the information list<user> user2 = session.selectlist ("Com.xiaoxin.demo.dto.selectUserAll");
	     for (User user:user2) {System.out.println (user.tostring ());
		
	} session.close ();
 }
	

}

Above all the success of their own testing, but the process of XML configuration of their own mistakes a lot, debugging many times before successfully debugging out, the following learning based on annotation annotation usage of mybatis
1. Interface for defining SQL mappings

Package com.xiaoxin.demo.mapper;

Import java.util.List;

Import Org.apache.ibatis.annotations.Delete;
Import Org.apache.ibatis.annotations.Insert;
Import Org.apache.ibatis.annotations.Select;
Import org.apache.ibatis.annotations.Update;

Import Com.xiaoxin.demo.dto.User;

Public interface Usermapper {
	@Select (' select * from user ') public
	list<user> Getselectuser ();
	@Update ("Update user set Username=#{username},userage=#{userage} where Id=#{id}") Public
	void Getupdateuser (user user);
	@Insert (Insert into user (Username,userage) VALUES (#{username},#{userage}); "
	public void Getinsertuser (user user);
	@Delete (' Delete from user where Id=#{id} ') public
	void getdeleteuser (int id);
	

}

2. Register this mapping interface in the MyBatis configuration file (Note class ...). ）

<mappers>
        <mapper resource= "Com/xiaoxin/demo/dto/user.xml"/>
        <mapper class= " Com.xiaoxin.demo.mapper.UserMapper "></mapper>
    </mappers>

Called in the DAO Class (here is the test)

Package com.xiaoxin.demo.dto;
Import java.io.IOException;
Import Java.io.Reader;

Import java.util.List;
Import org.apache.ibatis.io.Resources;
Import org.apache.ibatis.session.SqlSession;
Import Org.apache.ibatis.session.SqlSessionFactory;
Import Org.apache.ibatis.session.SqlSessionFactoryBuilder;

Import Org.junit.Test;

Import Com.xiaoxin.demo.mapper.UserMapper; public class Testuserannotation {@Test public void TestUser () throws ioexception{sqlsessionfactory sqlsessionf
	     Actory; 
	     Reader reader;
	     String resource = "Spring/configuration.xml";
	     Load a stream reader= Resources.getresourceasreader (Resource);
	     Generate Sqlsessionfactory Factory sqlsessionfactory = new Sqlsessionfactorybuilder (). build (reader);
	     
	     sqlsession session = Sqlsessionfactory.opensession ();
	     Usermapper usermapper = Session.getmapper (Usermapper.class);
Insert//USER user = new User ();
User.setusername ("Xinxin");
User.setuserage (20); UsermaPper.getinsertuser (user);
	     Session.commit ();
Delete//Usermapper.getdeleteuser (21);
	     Session.commit ();
Update will change the name of ID 19 to no change age to//user user = new User ();
User.setid (19);
User.setusername ("Xinxin");
User.setuserage (23);
Usermapper.getupdateuser (user);
	     Session.commit ();
	     Query list<user> users = Usermapper.getselectuser ();
	     for (User user2:users) {System.out.println (user2.tostring ());
	} session.close ();
 }

}

Test successful