MyBatis | Mapping Query Results to Arbitrary Java Objects | Basics
Data table
test_table
| id | value |
|---|---|
| 1 | fizz |
| 2 | buzz |
Source code
sample_mapper.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">
<mapper namespace="sample.mybatis">
<select id="selectTest" resultType="sample.mybatis.TestTable">
select * from test_table
</select>
</mapper>
TestTable.java
package sample.mybatis;
public class TestTable {
private int id;
private String value;
public void setValue(String value) {
System.out.println("setValue(" + value + ")");
this.value = value;
}
@Override
public String toString() {
return "TestTable [id=" + id + ", value=" + value + "]";
}
}
Main.java
package sample.mybatis;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class Main {
public static void main(String[] args) throws Exception {
try (InputStream in = Main.class.getResourceAsStream("/mybatis-config.xml")) {
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
try (SqlSession session = factory.openSession()) {
List<TestTable> result = session.selectList("sample.mybatis.selectTest");
System.out.println(result);
}
}
}
}
Execution result
[DEBUG] s.m.selectTest - ==> Preparing: select * from test_table
[DEBUG] s.m.selectTest - ==> Parameters:
setValue(fizz)
setValue(buzz)
[DEBUG] s.m.selectTest - <== Total: 2
[TestTable [id=1, value=fizz], TestTable [id=2, value=buzz]]
Explanation
- Specify the Java class you want to map query results to in resultType.
- Values are set on fields whose names match the column names.
- If a setter method exists, values are set through it. Otherwise, they are set directly on the fields.