字段名与实体类属性不匹配（[尚硅谷]_张晓飞_Mybatis 学习笔记二）

创建表

CREATE TABLE orders(
	order_id INT PRIMARY KEY AUTO_INCREMENT,
	order_no VARCHAR(20), 
	order_price FLOAT
);
INSERT INTO orders(order_no, order_price) VALUES('aaaa', 23);
INSERT INTO orders(order_no, order_price) VALUES('bbbb', 33);
INSERT INTO orders(order_no, order_price) VALUES('cccc', 22);

创建javabean类

package com.hb.bean;

public class Order {
	private int id;
	private String orderNo;
	private float price;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getOrderNo() {
		return orderNo;
	}
	public void setOrderNo(String orderNo) {
		this.orderNo = orderNo;
	}
	public float getPrice() {
		return price;
	}
	public void setPrice(float price) {
		this.price = price;
	}
	
	@Override
	public String toString() {
		return "Order [id=" + id + ", orderNo=" + orderNo + ", price=" + price + "]";
	}
	
}

创建映射XML文件

<?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="com.hb.bean.orderMapper">
	<!-- 这里namespace必须是“包名 + xml文件名”，不然要运行的时候要报错 “is not known to the MapperRegistry” -->
	<!-- 在SQL语句中定义别名，保证别名与类属性名一致 -->
	<select id="selectOrder" parameterType="int" resultType="com.hb.bean.Order">
		select
		order_id id, order_no orderNo,order_price price from orders where
		order_id=#{id}
	</select>


	<!-- 使用自定义类型，指名类属性与表字段的对应关系 -->
	<select id="selectOrderResultMap" parameterType="int" resultMap="orderResultMap">
		select * from orders where order_id=#{id}
	</select>

	<resultMap type="com.hb.bean.Order" id="orderResultMap">
		<id property="id" column="order_id" />
		<result property="orderNo" column="order_no" />
		<result property="price" column="order_price" />
	</resultMap>



</mapper>

配置mybatis总配置文件

<?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>

	<settings>
		<!-- changes from the defaults for testing -->
		<setting name="cacheEnabled" value="false" />
		<setting name="useGeneratedKeys" value="true" />
		<setting name="defaultExecutorType" value="REUSE" />
	</settings>

	<environments default="development">
		<environment id="development">
			<transactionManager type="jdbc" />
			<dataSource type="POOLED">
				<!-- 
				<property name="driver" value="oracle.jdbc.driver.OracleDriver"/> 
				<property name="url" value="jdbc:oracle:thin:@192.168.56.201:1521:system"/> 
				-->
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>

	<mappers>
		<mapper resource="com/hb/bean/orderMapper.xml" />
	</mappers>

</configuration>

创建测试类

package com.hb.test2;

import java.io.InputStream;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import com.hb.bean.Order;


public class Test2 {

	public static SqlSessionFactory sqlSessionFactory;
	public static SqlSession sqlSession;
	
	@Before
	public void init(){
		//"/"表示是在src根目录下
		String source = "config.xml";
		InputStream inputStream = Test2.class.getClassLoader().getResourceAsStream(source);
		
		try {
			sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//			sqlSession = sqlSessionFactory.openSession();
			//是否自动提交，默认不是自动提交的
			sqlSession = sqlSessionFactory.openSession(true);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	
	@Test
	public void selectById(){
		String statment = "com.hb.bean.orderMapper.selectOrder";
		Order order = sqlSession.selectOne(statment, 1);
		System.out.println(order);
	}
	
	@Test
	public void selectById2(){
		String statment = "com.hb.bean.orderMapper.selectOrderResultMap";
		Order order = sqlSession.selectOne(statment, 1);
		System.out.println(order);
	}
	
	
}