一.概述
二.注解实现简单的crud操作
2.1 新建工程如下
2.2 pom文件中依赖的配置
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
<scope>test</scope>
</dependency>
<!--mywql dueong -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.32</version>
</dependency>
<!--mybaits -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<!-- log4j-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<!-- 分页插件-->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>3.7.5</version>
</dependency>
<dependency>
<groupId>com.github.jsqlparser</groupId>
<artifactId>jsqlparser</artifactId>
<version>0.9.1</version>
</dependency>
2.3 实体层
package com.ljf.mybaits.relation.annotation.domain;
import java.util.Date;
/**
* @ClassName: User
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 20:02:38
* @Version: V1.0
**/
public class User {
private int id;
private String userName;
private Date birthday;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", userName='" + userName + '\'' +
", birthday=" + birthday +
'}';
}
}
2.4 dao层
package com.ljf.mybaits.relation.annotation.dao;
import com.ljf.mybaits.relation.annotation.domain.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import java.io.IOException;
import java.util.List;
public interface UserMapper {
@Insert("insert into tb_users values(#{id},#{userName},#{birthday})")
public void save(User user) throws IOException;
@Update("update tb_users set user_name=#{userName} where id=#{id}")
public void update(User user);
@Delete("delete from tb_users where id=#{id}")
public void delete(int id);
@Select("select id,user_name userName,birthday from tb_users where id=#{id}")
public User findById(int id);
@Select("select id,user_name userName,birthday from tb_users")
public List<User> findAll();
}
2.5 service层
service接口
package com.ljf.mybaits.relation.annotation.service;
import com.ljf.mybaits.relation.annotation.domain.User;
import org.apache.ibatis.annotations.Select;
import java.io.IOException;
import java.util.List;
public interface UserService {
public void save(User user) throws IOException;
public void update(User user) throws IOException;
public void delete(int id) throws IOException;
public User findById(int id) throws IOException;
public List<User> findAll() throws IOException;
}
service接口的实现层
package com.ljf.mybaits.relation.annotation.service.impl;
import com.ljf.mybaits.relation.annotation.dao.UserMapper;
import com.ljf.mybaits.relation.annotation.domain.User;
import com.ljf.mybaits.relation.annotation.service.UserService;
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;
import java.util.Date;
import java.util.List;
/**
* @ClassName: UserServiceImpl
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 20:17:17
* @Version: V1.0
**/
public class UserServiceImpl implements UserService {
private UserMapper mapper;
@Override
public void save(User user) throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
mapper.save(user);
}
@Override
public void update(User user) throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
mapper.update(user);
}
@Override
public void delete(int id) throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
mapper.delete(id);
}
@Override
public User findById(int id) throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
User u= mapper.findById(id);
return u;
}
@Override
public List<User> findAll() throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
List<User> userList=mapper.findAll();
return userList;
}
}
2.6 resource层
1.log4j的配置文件
######################
## set log levels
######################
log4j.rootLogger=DEBUG,info,CONSOLE,FILEOUT
#DEBUG,CONSOLE,FILE,ROLLING_FILE,MAIL,DATABASE
log4j.addivity.org.apache=true
######################
## CONSOLE Appender ##
######################
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.Threshold=DEBUG
log4j.appender.CONSOLE.Target=System.out
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
#log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n\u00A0
#log4j.appender.CONSOLE.layout.ConversionPattern=[start]%d{DATE}[DATE]%n%p[PRIORITY]%n%x[NDC]%n%t[THREAD] n%c[CATEGORY]%n%m[MESSAGE]%n%n
######################
## Rolling File Appender
######################
log4j.appender.FILEOUT=org.apache.log4j.RollingFileAppender
log4j.appender.FILEOUT.File=E:/logs/allError.log
#log4j.appender.FILEOUT.Threshold=ALL
log4j.appender.FILEOUT.Threshold=INFO
log4j.appender.FILEOUT.Append=true
log4j.appender.fileout.MaxFileSize=1000KB
#log4j.appender.ROLLING_FILE.MaxBackupIndex=1
log4j.appender.FILEOUT.layout=org.apache.log4j.PatternLayout
log4j.appender.FILEOUT.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
#log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n\u00A0
#######################
#info log
log4j.logger.info=info
log4j.appender.info=org.apache.log4j.DailyRollingFileAppender
log4j.appender.info.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.info.File=d:/info.log
log4j.appender.info.Append=true
log4j.appender.info.Threshold=INFO
log4j.appender.info.layout=org.apache.log4j.PatternLayout
log4j.appender.info.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
### File Appender
#######################
#log4j.appender.FILE=org.apache.log4j.FileAppender
#log4j.appender.FILE.File=E:/logs/all.log
#log4j.appender.FILE.Append=true
#log4j.appender.FILE.layout=org.apache.log4j.PatternLayout
#log4j.appender.CONSOLE.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH\:mm\:ss,SSS}][%c] \:%m%n
##log4j.appender.CONSOLE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n\u00A0
#####################
## Socket Appender
#####################
#log4j.appender.SOCKET=org.apache.log4j.RollingFileAppender
#log4j.appender.SOCKET.RemoteHost=localhost
#log4j.appender.SOCKET.Port=5001
#log4j.appender.SOCKET.LocationInfo=true
## Set up for Log Facter 5
#log4j.appender.SOCKET.layout=org.apache.log4j.PatternLayout
#log4j.appender.SOCET.layout.ConversionPattern=[start]%d{DATE}[DATE]%n%p[PRIORITY]%n%x[NDC]%n%t[THREAD]%n%c[CATEGORY]%n%m[MESSAGE]%n%n
#########################
## Log Factor 5 Appender
#########################
#log4j.appender.LF5_APPENDER=org.apache.log4j.lf5.LF5Appender
#log4j.appender.LF5_APPENDER.MaxNumberOfRecords=2000
########################
## SMTP Appender
########################
#log4j.appender.MAIL=org.apache.log4j.net.SMTPAppender
#log4j.appender.MAIL.Threshold=FATAL
#log4j.appender.MAIL.BufferSize=10
#[email protected]
#log4j.appender.MAIL.SMTPHost=mail.openwolf.com
#log4j.appender.MAIL.Subject=Log4J Message
#[email protected]
#log4j.appender.MAIL.layout=org.apache.log4j.PatternLayout
#log4j.appender.MAIL.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n
#########################
## JDBC Appender
########################
#log4j.appender.DATABASE=org.apache.log4j.jdbc.JDBCAppender
#log4j.appender.DATABASE.URL=jdbc:mysql://localhost:3306/test
#log4j.appender.DATABASE.driver=com.mysql.jdbc.Driver
#log4j.appender.DATABASE.user=root
#log4j.appender.DATABASE.password=root
#log4j.appender.DATABASE.sql=INSERT INTO LOG4J (Message) VALUES ('[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n')
#log4j.appender.DATABASE.layout=org.apache.log4j.PatternLayout
#log4j.appender.DATABASE.layout.ConversionPattern=[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n
#log4j.appender.A1=org.apache.log4j.DailyRollingFileAppender
#log4j.appender.A1.File=SampleMessages.log4j
#log4j.appender.A1.DatePattern=yyyyMMdd-HH'.log4j'
#log4j.appender.A1.layout=org.apache.log4j.xml.XMLLayout
####################
### myself Appender
####################
#log4j.appender.im = net.cybercorlin.util.logger.appender.IMAppender
#log4j.appender.im.host = mail.cybercorlin.net
#log4j.appender.im.username = username
#log4j.appender.im.password = password
#log4j.appender.im.recipient = [email protected]
#log4j.appender.im.layout=org.apache.log4j.PatternLayout
#log4j.appender.im.layout.ConversionPattern =[framework] %d - %c -%-4r [%t] %-5p %c %x - %m%n
2.mybaits-jdbc的配置文件
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/nongda
jdbc.username=root
jdbc.password=
3.mybaitsconfig的配置文件
<?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>
<properties resource="mybaits-jdbc.properties"></properties>
<!-- 起别名-->
<typeAliases>
<typeAlias type="com.ljf.mybaits.relation.annotation.domain.User" alias="user"></typeAlias>
</typeAliases>
<!-- 注册类型注册器
<typeHandlers>
<typeHandler handler="com.mybaits.demo.handler.DataTypeTransfer"></typeHandler>
</typeHandlers>
-->
<!--配置分页插件 -->
<plugins>
<plugin interceptor="com.github.pagehelper.PageHelper">
<property name="dialect" value="mysql"/>
</plugin>
</plugins>
<!-- 数据源环境 -->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"></transactionManager>
<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>
<!-- xxxmapper.xml都要在mybaits.config.xml文件中注册-->
<!--加载映射关系-->
<mappers>
<!--指定接口所在的包-->
<package name="com.ljf.mybaits.relation.annotation.dao"></package>
</mappers>
</configuration>
2.7 调用
package com.ljf.mybaits.relation.annotation;
import com.ljf.mybaits.relation.annotation.domain.User;
import com.ljf.mybaits.relation.annotation.service.UserService;
import com.ljf.mybaits.relation.annotation.service.impl.UserServiceImpl;
import java.io.IOException;
import java.util.Date;
import java.util.List;
/**
* Hello world!
*
*/
public class App
{
public static void main( String[] args ) throws IOException {
//add();
// update();
findAll();
findSingleUser();
delete();
findSingleUser();
System.out.println( "Hello World!" );
}
/**
* @author liujianfu
* @description 添加
* @date 2021/2/18 20:45
* @param []
* @return void
*/
public static void add() throws IOException {
UserService us=new UserServiceImpl();
User user = new User();
user.setUserName("beijing");
user.setId(23);
user.setBirthday(new Date());
us.save(user);
}
//修改
public static void update() throws IOException {
UserService us=new UserServiceImpl();
User user = new User();
user.setId(73);
user.setUserName("tianjin");
us.update(user);
}
//查询
public static void findAll() throws IOException {
UserService us=new UserServiceImpl();
List<User> userList= us.findAll();
for(User u:userList){
System.out.println("u:"+u);
}
}
//单个查询
public static void findSingleUser() throws IOException {
UserService us=new UserServiceImpl();
User u= us.findById(23);
System.out.println("u:"+u);
}
//删除
public static void delete() throws IOException {
UserService us=new UserServiceImpl();
us.delete(23);
}
}
三.1:1的关系
3.0 背景描述
订单和用户是1对1的关系
3.1 数据库的设计
CREATE TABLE `tb_users` (
`id` int(11) NOT NULL,
`user_name` varchar(255) DEFAULT NULL,
`birthday` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `tb_orders` (
`id` int(11) NOT NULL,
`order_time` datetime NOT NULL,
`total` double(255,0) NOT NULL,
`uid` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
3.2 实体类的设计
package com.ljf.mybaits.relation.annotation.domain;
import java.util.Date;
/**
* @ClassName: Order
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 22:29:25
* @Version: V1.0
**/
public class Order {
private int id;
private Date orderTime;
private double total;
//当前订单属于哪一个用户
private User user;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Date getOrderTime() {
return orderTime;
}
public void setOrderTime(Date orderTime) {
this.orderTime = orderTime;
}
public double getTotal() {
return total;
}
public void setTotal(double total) {
this.total = total;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
@Override
public String toString() {
return "Order{" +
"id=" + id +
", orderTime=" + orderTime +
", total=" + total +
", user=" + user +
'}';
}
}
3.3 orderMapper配置文件
两种方式实现1:1的关系的查询
package com.ljf.mybaits.relation.annotation.dao;
import com.ljf.mybaits.relation.annotation.domain.Order;
import com.ljf.mybaits.relation.annotation.domain.User;
import org.apache.ibatis.annotations.One;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import java.util.List;
public interface OrderMapper {
//方式一
@Select("select * from tb_orders")
@Results({
@Result(column = "id",property = "id"),
@Result(column = "order_time",property = "orderTime"),
@Result(column = "total",property = "total"),
@Result(
property = "user", //要封装的属性名称
column = "uid", //uid为tb_orders表中的字段,表示是外键,是关联用户表tb_user
javaType = User.class, //要封装的实体类型
//select属性 代表查询那个接口的方法获得数据
one = @One(select = "com.ljf.mybaits.relation.annotation.dao.UserMapper.findById")
)
})
public List<Order> findAll();
//方式二
@Select(" SELECT o.id oid,o.order_time,o.total,u.id,u.user_name,u.birthday FROM tb_orders o,tb_users u WHERE o.uid=u.id")
@Results({
@Result(column = "oid",property = "id"),
@Result(column = "order_time",property = "orderTime"),
@Result(column = "total",property = "total"),
@Result(column = "uid",property = "user.id"),
@Result(column = "user_name",property = "user.userName"),
@Result(column = "birthday",property = "user.birthday")
})
public List<Order> findAll2();
}
3.4 service层
service接口
package com.ljf.mybaits.relation.annotation.service;
import com.ljf.mybaits.relation.annotation.domain.Order;
import java.io.IOException;
import java.util.List;
public interface OrderService {
public List<Order> findAll() throws IOException;
public List<Order> findAll2() throws IOException;
}
service的实现层
package com.ljf.mybaits.relation.annotation.service.impl;
import com.ljf.mybaits.relation.annotation.dao.OrderMapper;
import com.ljf.mybaits.relation.annotation.dao.UserMapper;
import com.ljf.mybaits.relation.annotation.domain.Order;
import com.ljf.mybaits.relation.annotation.service.OrderService;
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;
import java.util.List;
/**
* @ClassName: OrderServiceImpl
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 22:03:22
* @Version: V1.0
**/
public class OrderServiceImpl implements OrderService {
private OrderMapper mapper;
@Override
public List<Order> findAll() throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(OrderMapper.class);
List<Order> orderList= mapper.findAll();
return orderList;
}
@Override
public List<Order> findAll2() throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(OrderMapper.class);
List<Order> orderList= mapper.findAll2();
return orderList;
}
}
3.5 调用
package com.ljf.mybaits.relation.annotation;
import com.ljf.mybaits.relation.annotation.domain.Order;
import com.ljf.mybaits.relation.annotation.service.OrderService;
import com.ljf.mybaits.relation.annotation.service.impl.OrderServiceImpl;
import java.io.IOException;
import java.util.List;
/**
* @ClassName: APP2
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 22:02:14
* @Version: V1.0
**/
public class APP2 {
public static void main(String[] args) throws IOException {
OrderService orderService=new OrderServiceImpl();
List<Order> orderList=orderService.findAll();
for(Order order:orderList){
System.out.println("order:"+order);
}
System.out.println("============");
List<Order> orderList2=orderService.findAll2();
for(Order order:orderList2){
System.out.println("order2:"+order);
}
}
}
四.1:n的关系
4.1 修改实体类
package com.ljf.mybaits.relation.annotation.domain;
import java.util.Date;
import java.util.List;
/**
* @ClassName: User
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 20:02:38
* @Version: V1.0
**/
public class User {
private int id;
private String userName;
private Date birthday;
//描述的是当前用户具有的订单
private List<Order> orderList;
public List<Order> getOrderList() {
return orderList;
}
public void setOrderList(List<Order> orderList) {
this.orderList = orderList;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", userName='" + userName + '\'' +
", birthday=" + birthday +
", orderList=" + orderList +
'}';
}
}
4.2 orderMapper
//多对一使用,被usermapper中的findUserAndRoleAll方法调用
@Select("select id id,order_time orderTime,total from tb_orders where uid=#{uid}")
public List<Order> findByUid(int uid);
4.3 userMapper
//配置多对1的关系
@Select("SELECT * FROM tb_users")
@Results({
@Result(id = true,column = "id",property = "id"),
@Result(column = "user_name",property = "userName"),
@Result(column = "birthday",property = "birthday"),
@Result(
property = "orderList",
column = "id",
javaType = List.class,
//一对多的配置,多是order
many = @Many(select = "com.ljf.mybaits.relation.annotation.dao.OrderMapper.findByUid")
)
})
public List<User> findUserAndOrderAll();
4.4 service层
service接口
//查询1对多的查询
public List<User> findUserAndOrderAll() throws IOException;
serviceimpl接口
@Override
public List<User> findUserAndRoleAll() throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
List<User> userList=mapper.findUserAndOrderAll();
return userList;
}
4.5 调用
package com.ljf.mybaits.relation.annotation;
import com.ljf.mybaits.relation.annotation.domain.User;
import com.ljf.mybaits.relation.annotation.service.UserService;
import com.ljf.mybaits.relation.annotation.service.impl.UserServiceImpl;
import java.io.IOException;
import java.util.List;
/**
* @ClassName: APP3
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/19 09:53:12
* @Version: V1.0
**/
public class APP3 {
public static void main(String[] args) throws IOException {
UserService us=new UserServiceImpl();
List<User> userList= us.findUserAndOrderAll();
for(User u:userList){
System.out.println("u:"+u);
}
}
}
五.n:n的关系
5.1 数据库设计
5.2 实体设计
1.role
package com.ljf.mybaits.relation.annotation.domain;
/**
* @ClassName: Role
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 14:42:38
* @Version: V1.0
**/
public class Role {
private int id;
private String roleName;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getRoleName() {
return roleName;
}
public void setRoleName(String roleName) {
this.roleName = roleName;
}
@Override
public String toString() {
return "Role{" +
"id=" + id +
", roleName='" + roleName + '\'' +
'}';
}
}
2.user
package com.ljf.mybaits.relation.annotation.domain;
import java.util.Date;
import java.util.List;
/**
* @ClassName: User
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/18 20:02:38
* @Version: V1.0
**/
public class User {
private int id;
private String userName;
private Date birthday;
//描述的是当前用户具有的订单
private List<Order> orderList;
public List<Order> getOrderList() {
return orderList;
}
public void setOrderList(List<Order> orderList) {
this.orderList = orderList;
}
//当前用户具备哪些角色
private List<Role> roleList;
public List<Role> getRoleList() {
return roleList;
}
public void setRoleList(List<Role> roleList) {
this.roleList = roleList;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", userName='" + userName + '\'' +
", birthday=" + birthday +
", orderList=" + orderList +
", roleList=" + roleList +
'}';
}
}
5.3 UserMapper配置
//n:n的关系
@Select("SELECT * FROM tb_users")
@Results({
@Result(id = true,column = "id",property = "id"),
@Result(column = "user_name",property = "userName"),
@Result(column = "birthday",property = "birthday"),
@Result(
property = "roleList",
column = "id",
javaType = List.class,
many = @Many(select = "com.ljf.mybaits.relation.annotation.dao.RoleMapper.findByUid")
)
})
public List<User> findUserAndRoleAll();
5.4 roleMapper
package com.ljf.mybaits.relation.annotation.dao;
import com.ljf.mybaits.relation.annotation.domain.Role;
import org.apache.ibatis.annotations.Select;
import java.util.List;
public interface RoleMapper {
@Select("SELECT a.uid,a.rid,b.id,b.role_name roleName FROM tb_user_role a,tb_role b WHERE a.rid=b.id AND a.uid=#{uid}")
public List<Role> findByUid(int uid);
}
5.5 service层
service接口
//查询n对多的查询
public List<User> findUserAndRoleAll() throws IOException;
service的实现层
@Override
public List<User> findUserAndRoleAll() throws IOException {
InputStream resourceAsStream = Resources.getResourceAsStream("mybaitsConfig.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
SqlSession sqlSession = sqlSessionFactory.openSession(true);
mapper = sqlSession.getMapper(UserMapper.class);
List<User> userList=mapper.findUserAndRoleAll();
return userList;
}
5.6 调用
package com.ljf.mybaits.relation.annotation;
import com.ljf.mybaits.relation.annotation.domain.User;
import com.ljf.mybaits.relation.annotation.service.UserService;
import com.ljf.mybaits.relation.annotation.service.impl.UserServiceImpl;
import java.io.IOException;
import java.util.List;
/**
* @ClassName: APP4
* @Description: TODO
* @Author: liujianfu
* @Date: 2021/02/19 10:43:23
* @Version: V1.0
**/
public class APP4 {
public static void main(String[] args) throws IOException {
UserService us=new UserServiceImpl();
List<User> userList= us.findUserAndRoleAll();
for(User u:userList){
System.out.println("u:"+u);
}
}
}