mybatis Plus 多表联合查询

//实体类package com.sk.skkill.entity;

import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;

import java.io.Serializable;
import java.util.Date;
import java.util.List;

@TableName("orders")
@Data
public class Order implements Serializable
{
    public static final long  serialVersionUID =1L;
    private String id;
    private String orderName;
    private Date createTime;
    private Date updateTime;
    private String userID;

    @TableField(exist = false)
    private  List<Users>  listUsers;

    public Order(){

    }

    public Order(String id, String orderName) {
        this.id = id;
        this.orderName = orderName;
    }

}

//dao层

package com.sk.skkill.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.sk.skkill.entity.Order;
import com.sun.javafx.collections.MappingChange;
import org.apache.ibatis.annotations.Select;

import java.util.List;
import java.util.Map;

public interface OrderMapper extends BaseMapper<Order>
{
List<Order> selectOrder();
int addOrder(Order order);

//多表联合查询 按条件orderID
@Select("select t1.*,t2.user_name,t2.nick_name from orders t1 LEFT JOIN  users t2  ON t1.user_id =t2.id WHERE t1.user_id= #{id}")
 List<Map<String,Object>> orderUserList(Page<Map<String,Object>> page,String id);

}

//service层

package com.sk.skkill.service;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.IService;
import com.sk.skkill.entity.Order;

import java.util.List;
import java.util.Map;

public interface OrderService extends IService<Order>
{
    List<Order> selectOrder();
    int addOrder(Order order);
//    List<Map<String,Object>> orderUserList(Page<Map<String,Object>> page, String id);
    Page<Map<String,Object>> selectListPage(int current,int number,String id);
}

//serviceImpl层

package com.sk.skkill.service.impl;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.sk.skkill.entity.Order;
import com.sk.skkill.mapper.OrderMapper;
import com.sk.skkill.service.OrderService;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;

@Service
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements OrderService
{

    @Override
    public List<Order> selectOrder() {
        return baseMapper.selectList(null);
    }

    @Override
    public int addOrder(Order order) {
        return baseMapper.insert(order);
    }

    @Override
    public Page<Map<String, Object>> selectListPage(int current, int number,String id) {
        //新建分页
        Page<Map<String,Object>> page =new Page<Map<String,Object>>(current,number);
        //返回结果
        return  page.setRecords(this.baseMapper.orderUserList(page,id));
    }

}

//controller层

 

package com.sk.skkill.controller;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.sk.skkill.entity.Order;
import com.sk.skkill.service.impl.OrderServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("order")
public class OrderController
{
    @Autowired
    private OrderServiceImpl service;

    @RequestMapping("selectOrder")
    public List<Order> selectOrder()
    {
        return service.selectOrder();
    }
    @RequestMapping("addOrder")
  public  int addOrder(Order order){
        order=new Order("FGGG","蒙牛MILK");
       return service.addOrder(order);

  }
  @RequestMapping("selectListPage")
    public  List<Map<String,Object>>   selectListPage(String id)
    {
        Page<Map<String, Object>> page = service.selectListPage(1, 2,id);
        return page.getRecords();
    }

}