-de8bd8f33c3e44a59907dafe1884f228.png)
准备
# jdbc.properties
jdbc.url=jdbc:mysql://192.168.208.192:3306/test?characterEncoding=utf-8
jdbc.driver=com.mysql.jdbc.Driver
jdbc.username=root
jdbc.password=root
# log4j.properties
log4j.rootLogger = debug,stdout,E
### 输出信息到控制抬 ###
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n
### 输出DEBUG 级别以上的日志到=E://logs/error.log ###
log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = E://logs/log.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = DEBUG
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
### 输出ERROR 级别以上的日志到=E://logs/error.log ###
log4j.appender.E = org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.File =E://logs/error.log
log4j.appender.E.Append = true
log4j.appender.E.Threshold = ERROR
log4j.appender.E.layout = org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n
<!-- mybatis/SqlMapConfig.xml -->
<?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>
<!--
加载属性文件
先加载内部标签，再加载外部文件，名称一致时，会覆盖内部标签内容
-->
<properties resource="jdbc.properties"/>
<!--别名扫描-->
<typeAliases>
<package name="com.zze.mybatis.pojo" />
</typeAliases>
<!-- 和 spring 整合后 environments配置将废除-->
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理-->
<transactionManager type="JDBC"/>
<!-- 数据库连接池-->
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments>
<!-- 加载映射文件 -->
<mappers>
<package name="com.zze.mybatis.mapper"/>
</mappers>
</configuration>
// com.zze.mybatis.pojo.User
import java.util.Date;
public class User {
private Integer id;
private String name;
private Date birthday;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", birthday=" + birthday +
'}';
}
}
// com.zze.mybatis.util.SqlSessionFactoryUtil
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
public class SqlSessionFactoryUtil {
private static SqlSessionFactory sqlSessionFactory;
static {
// 创建 SqlSessionFactoryBuilder 对象
SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
// 创建核心配置文件的输入流
InputStream resourceAsStream = null;
try {
resourceAsStream = Resources.getResourceAsStream("mybatis/SqlMapConfig.xml");
} catch (IOException e) {
e.printStackTrace();
}
// 创建 Session 工厂
sqlSessionFactory = sqlSessionFactoryBuilder.build(resourceAsStream);
}
/**
* 打开一个 Session
*
* @return SqlSession 实例
*/
public static SqlSession openSession() {
return sqlSessionFactory.openSession();
}
/**
* 打开一个 Session
*
* @param autoCommit 是否自动提交事务
* @return SqlSession 实例
*/
public static SqlSession openSession(Boolean autoCommit) {
return sqlSessionFactory.openSession(autoCommit);
}
}
<!-- pom.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.zze.mybatis</groupId>
<artifactId>mybatis_test2</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.8</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.0-rc1</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.0-rc1</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.11.0.GA</version>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>asm</groupId>
<artifactId>asm</artifactId>
<version>3.3.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.37</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
示例
一对一
新建与用户关联的订单表和 POJO，配置映射文件：
// com.zze.mybatis.pojo.Order
import java.util.Date;
public class Order {
private Integer id;
private Integer uId;
private Double totalPrice;
private Date createDate;
/*
Order 一对一关联 User
*/
private User user;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getuId() {
return uId;
}
public void setuId(Integer uId) {
this.uId = uId;
}
public Double getTotalPrice() {
return totalPrice;
}
public void setTotalPrice(Double totalPrice) {
this.totalPrice = totalPrice;
}
public Date getCreateDate() {
return createDate;
}
public void setCreateDate(Date createDate) {
this.createDate = createDate;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
@Override
public String toString() {
return "Order{" +
"id=" + id +
", uId=" + uId +
", TotalPrice=" + totalPrice +
", createDate=" + createDate +
", user=" + user +
'}';
}
}
<!-- com/zze/mybatis/mapper/OrderMapper.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="com.zze.mybatis.mapper.OrderMapper">
<resultMap id="orderMap" type="order">
<!--
注意：
在关联查询时，每个映射字段都需配置，不可省略。
-->
<id property="id" column="oid"/>
<result property="uId" column="uid"/>
<result property="totalPrice" column="totalPrice"/>
<result property="createDate" column="createdate"/>
<!--
通过 association 配置一对一关系
-->
<association property="user" javaType="user">
<id property="id" column="uid"/>
<result property="name" column="name"/>
<result property="birthday" column="birthday"/>
</association>
</resultMap>
<select id="getAll" resultMap="orderMap">
select o1.id oid,o1.uid,totalPrice,createdate,name,birthday from `order` o1 left join `user` u1 on o1.uid = u1.id;
</select>
</mapper>
package com.zze.mybatis.test;
import com.zze.mybatis.mapper.OrderMapper;
import com.zze.mybatis.pojo.Order;
import com.zze.mybatis.util.SqlSessionFactoryUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Before;
import org.junit.Test;
import java.util.List;
public class OrderTest {
private OrderMapper orderMapper;
@Before
public void init() {
SqlSession sqlSession = SqlSessionFactoryUtil.openSession();
orderMapper = sqlSession.getMapper(OrderMapper.class);
}
@Test
public void test() {
List<Order> orderList = orderMapper.getAll();
orderList.forEach(o -> System.out.println(o));
/*
==> Preparing: select o1.id oid,o1.uid,totalPrice,createdate,name,birthday from `order` o1 left join `user` u1 on o1.uid = u1.id;
Order{id=1, uId=1, TotalPrice=324.0, createDate=Thu Mar 21 11:10:20 CST 2019, user=User{id=1, name='张三', birthday=Thu Jan 01 00:00:00 CST 1998}}
Order{id=3, uId=1, TotalPrice=543.0, createDate=Mon Mar 18 11:11:05 CST 2019, user=User{id=1, name='张三', birthday=Thu Jan 01 00:00:00 CST 1998}}
Order{id=2, uId=3, TotalPrice=23.0, createDate=Fri Mar 01 06:04:07 CST 2019, user=User{id=3, name='李四', birthday=Thu Jan 01 00:00:00 CST 1998}}
*/
}
}
一对多
修改用户的 POJO 关联订单，配置映射文件：
// com.zze.mybatis.pojo.User
import java.util.Date;
import java.util.List;
public class User {
private Integer id;
private String name;
private Date birthday;
/*
User 一对多关联 Order
*/
private List<Order> orders;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public List<Order> getOrders() {
return orders;
}
public void setOrders(List<Order> orders) {
this.orders = orders;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", birthday=" + birthday +
'}';
}
}
<!-- com/zze/mybatis/mapper/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">
<mapper namespace="com.zze.mybatis.mapper.UserMapper">
<resultMap id="userMap" type="user">
<id property="id" column="uId"/>
<result property="name" column="name"/>
<result property="birthday" column="birthday"/>
<!--
使用 collection 标签建立一对多关系
注意，这里使用的是 ofType，而一对一关联时使用的是 javaType
-->
<collection property="orders" ofType="order">
<id property="id" column="oId"/>
<result property="totalPrice" column="totalPrice"/>
<result property="createDate" column="createDate"/>
<result property="uId" column="uId"/>
</collection>
</resultMap>
<select id="getAll" resultMap="userMap">
select u1.id uId,o1.id oId,totalPrice,createdate,name,birthday from `user` u1 left join `order` o1 on u1.id=o1.uid;
</select>
</mapper>
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