MyBatis series: 1, Getting Started

MyBatis no need for me to reports, this series is pure dry, with no nonsense.

1. Create a maven project, introduced mysql maven drive and mybatis of reference

    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.3</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.18 </version>
    </dependency>

2. Write mybatis configuration files are placed in the following resources directory name at random

<?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>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
   
  </mappers>
</configuration>

SqlSessionFactory 3. Create a way to use XML

// your profile name 
   String Source = "the mybatis-config.xml" ; 
// load configuration file 
        InputStream inputStream = Resources.getResourceAsStream (Source); 
        SqlSessionFactory SqlSessionFactory = new new . The SqlSessionFactoryBuilder () Build (inputStream);

4. Create an entity class to complete a basic query

Create a JavaBean-Blog

public class Blog {

    private int id;

    private String name;

    private  String remark;

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getRemark() {
        return remark;
    }

    public void setRemark(String remark) {
        this.remark = remark;
    }

    @Override
    public String toString()
    {
        return  this.name+this.remark;

    }
}

Blog creation corresponding Mapper interfaces BlogMapper, define a query method within an interface

public interface BlogMapper {

   public Blog selectBlog(int id);
   
}

Creating BlogMapper corresponding XML mapping file BlogMapper

namespace to be consistent with the interface name

id select a node and to a method name as defined in the interface

resultType entity type is set to return

<?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="BlogMapper">
    <select id="selectBlog" resultType="Blog">
        select * from Blog where id=#{id}
    </select>
</mapper>

Then we need to write our new mapper BlogMapper the first step in setting the node configuration file

    <mappers>
       <mapper resource="BlogMapper.xml"></mapper>
    </mappers>

5. Create a Blog above and the same table in the database and arranged to increment id, adding a test data

Write the following code in the main process, reads from the database and the corresponding data is output to the console

    public static void main(String[] str) throws IOException {
        String source = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(source);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        BlogMapper mapper = sqlSession.getMapper(BlogMapper.class);
        Blog blog = mapper.selectBlog(1);
        System.out.println( blog);
    }

This article describes the Mybatis to read from the factory to create a basic flow of data from the database, the next will be described in detail the role of each node.

MyBatis series: 1, Getting Started

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