MyBatis (i) installation

1. Create a Web project, add a jar package

2. Create the experimental table user_t

3. Create the Conf.xml file under SRC, as follows

<?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>    <Environmentsdefault= "Development">        <EnvironmentID= "Development">            <TransactionManagertype= "JDBC" />            <!--Configure database connection information -            <DataSourcetype= "Pooled">                < Propertyname= "Driver"value= "Com.mysql.jdbc.Driver" />                < Propertyname= "url"value= "Jdbc:mysql://localhost/mi" />                < Propertyname= "username"value= "root" />                < Propertyname= "Password"value= "Dbdaocom" />            </DataSource>        </Environment>    </Environments>    </Configuration>

2. Define the entity class corresponding to the table,

 Package com.mi.entity;  Public class User {    privateint  ID;     Private String userName;     Private String password;     Private Integer age; ...}

3. Define the SQL mapping file that operates the users table Usermapper.xml

<?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 "><Mappernamespace= "Com.mi.dao.UserInfoMapper">         <SelectID= "Queryuserinfo"Resulttype= "Com.mi.entity.User">SELECT id,user_name username,age from user_t where 1=1</Select>    <SelectID= "GetCount"Resulttype= "int">SELECT Count (*) from user_t</Select>    </Mapper>

4. Register the Usermapper.xml file in the Conf.xml file

<?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>    <Environmentsdefault= "Development">        <EnvironmentID= "Development">            <TransactionManagertype= "JDBC" />            <!--Configure database connection information -            <DataSourcetype= "Pooled">                < Propertyname= "Driver"value= "Com.mysql.jdbc.Driver" />                < Propertyname= "url"value= "Jdbc:mysql://localhost/mi" />                < Propertyname= "username"value= "root" />                < Propertyname= "Password"value= "Dbdaocom" />            </DataSource>        </Environment>    </Environments>    <mappers>        <MapperResource= "Com/mi/mapping/userinfomapper.xml"/><!--Register the Usermapper.xml file, -    </mappers></Configuration>

5. Write the test code: Execute the defined SELECT statement

To create a Test1 class, write the following test code:

 PackageCom.mi.demo;ImportJava.io.InputStream;Importorg.apache.ibatis.session.SqlSession;Importorg.apache.ibatis.session.SqlSessionFactory;ImportOrg.apache.ibatis.session.SqlSessionFactoryBuilder;ImportCom.mi.entity.User; Public classTest1 { Public Static voidMain (string[] args) {//configuration file for MyBatisString resource = "Conf.xml"; //load the MyBatis configuration file using the ClassLoader (it also loads the associated mapping file)InputStream is = Test1.class. getClassLoader (). getResourceAsStream (Resource); //building a factory in sqlsessionSqlsessionfactory sessionfactory =NewSqlsessionfactorybuilder (). Build (IS); //use the resources class provided by MyBatis to load the MyBatis configuration file (It also loads the associated mapping file)//Reader reader = resources.getresourceasreader (Resource); //building a factory in sqlsession//sqlsessionfactory sessionfactory = new Sqlsessionfactorybuilder (). build (reader); //Create a sqlsession that can execute SQL in the mapping filesqlsession session =sessionfactory.opensession (); /*** Mapped SQL identification string, * Com.mi.mapping.UserInfoMapper is the value of the namespace attribute of the mapper tag in the Userinfomapper.xml file, * Queryuserinfo is the id attribute value of the select tag, and the value of the id attribute of the SELECT tag can be used to find the SQL to execute*/String Statement= "Com.mi.mapping.UserInfoMapper.queryUserInfo";//identity string for mapping SQLUser user = Session.selectone (statement,1);//executes a query that returns the SQL for a unique user objectSystem.out.println (User.getid ());        System.out.println (User.getusername ());    System.out.println (User.getage ()); }}

The results are as follows:

MyBatis (i) installation