【Mybaits学习】06_ 一对一查询

主要通过员工与部门属性的关联测试代码说明

1、环境准备,建表

员工表

部门表

2、创建表所对应的实体类

员工类

package nh.ui.automation.tools.Mybaits;

/**
 * 项目 ：UI自动化测试 Mybaits 类描述：
 * 
 * @author Eric
 * @date 2017年3月4日 nh.ui.automation.tools.Mybaits
 */
public class Employee {
	private int id;
	private String name;
	private Department department;

	/**
	 * 
	 */
	public Employee() {
		super();
	}

	/**
	 * @param id
	 * @param name
	 * @param department
	 */
	public Employee(int id, String name, Department department) {
		super();
		this.id = id;
		this.name = name;
		this.department = department;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		return "Employee [id=" + id + ", name=" + name + ", department=" + department + "]";
	}

	/**
	 * @return the id
	 */
	public int getId() {
		return id;
	}

	/**
	 * @param id
	 *            the id to set
	 */
	public void setId(int id) {
		this.id = id;
	}

	/**
	 * @return the name
	 */
	public String getName() {
		return name;
	}

	/**
	 * @param name
	 *            the name to set
	 */
	public void setName(String name) {
		this.name = name;
	}

	/**
	 * @return the department
	 */
	public Department getDepartment() {
		return department;
	}

	/**
	 * @param department
	 *            the department to set
	 */
	public void setDepartment(Department department) {
		this.department = department;
	}

}

　部门类

package nh.ui.automation.tools.Mybaits;

/**
 * 项目 ：UI自动化测试 Mybaits 类描述：
 * 
 * @author Eric
 * @date 2017年3月4日 nh.ui.automation.tools.Mybaits
 */
public class Department {
    private int id;
    private String name;

    /**
     * 
     */
    public Department() {
        super();
    }

    /**
     * @param id
     * @param name
     */
    public Department(int id, String name) {
        super();
        this.id = id;
        this.name = name;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return "Department [id=" + id + ", name=" + name + "]";
    }

    /**
     * @return the id
     */
    public int getId() {
        return id;
    }

    /**
     * @param id
     *            the id to set
     */
    public void setId(int id) {
        this.id = id;
    }

    /**
     * @return the name
     */
    public String getName() {
        return name;
    }

    /**
     * @param name
     *            the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

}

3、创建employeeMapper映射，查询所有员工信息

<?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="nh.ui.automation.tools.Mybaits.Order.employMapper">
    <select id="getAllEmployee" resultType="nh.ui.automation.tools.Mybaits.Employee"
        resultMap="employeeMap">
        select * from employee empl, department depart where
        empl.department_id= depart.id
    </select>

    <resultMap type="nh.ui.automation.tools.Mybaits.Employee" id="employeeMap">
        <id property="id" column="id" />
        <result property="name" column="name" />
        <association property="department"
            javaType="nh.ui.automation.tools.Mybaits.Department">
            <id property="id" column="id" />
            <result property="name" column="name" />
        </association>
    </resultMap>
</mapper>

4、在Mybaits配置文件中注册employMapper

<?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>
    <properties resource="db.properties"></properties>

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

    <mappers>
        <mapper resource="Mappings/userMapper.xml" />
        <mapper resource="Mappings/orderMapper.xml" />
        <mapper resource="Mappings/employMapper.xml" />
        <mapper class="nh.ui.automation.tools.mapper.UserMapper" />

    </mappers>
</configuration>

5、测试代码

package nh.ui.automation.tools.Mybaits;

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;

import nh.ui.automation.tools.mapper.UserMapper;

/**
 * Hello world!
 *
 */
public class EmployeeTest 
{
    public static void main( String[] args )
    {
        /**
         * 1,加载mybaits的配置文件
         * 2,构建sqlsession工厂
         * 3,创建能执行sql的会话
         * 4,映射sql的标识字符串
         * 5,执行sql
         * 6,打印结果
         */
        
        String myBaitsConifg = "Mybaits.xml";
        InputStream loadConfig = EmployeeTest.class.getClassLoader().getResourceAsStream(myBaitsConifg);
        
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(loadConfig);
        SqlSession sqlSession = sessionFactory.openSession(true);
    
        /**
         * <association property="department"
            javaType="nh.ui.automation.tools.Mybaits.Department">
            <id property="id" column="id" />
            <result property="name" column="name" />
         *    </association>
         *association  用于一对一查询
         *property Java POJO属性
         *javaType 对象属性的类型
         *column  数据库列名
         *
         */
        String statement = "nh.ui.automation.tools.Mybaits.Order.employMapper.getAllEmployee";
        List<Object> selectList = sqlSession.selectList(statement);
        System.out.println(selectList);
        
    }
}

6、观察结果

2017-03-05 00:11:57,563 [main] DEBUG [nh.ui.automation.tools.Mybaits.Order.employMapper.getAllEmployee] - ==>  Preparing: select * from employee empl, department depart where empl.department_id= depart.id 
2017-03-05 00:11:57,593 [main] DEBUG [nh.ui.automation.tools.Mybaits.Order.employMapper.getAllEmployee] - ==> Parameters: 
2017-03-05 00:11:57,604 [main] DEBUG [nh.ui.automation.tools.Mybaits.Order.employMapper.getAllEmployee] - <==      Total: 2
[Employee [id=1, name=niuh, department=Department [id=1, name=niuh]], Employee [id=3, name=kk, department=Department [id=3, name=kk]]]