MyBatis快速入门——第四章、mybatis动态sql_foreach

MyBatis快速入门——第四章、mybatis动态sql_foreach

目录

循环测试配【mapper.xml】置文件编写

DAO层：

参数传递：

测试类： 

查询结果：

循环测试配【mapper.xml】置文件编写

我这里便利的是【uuid()】的id，故而是字符串。

<?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.item.mapper.ProductMapper">
    <select id="GetInfo" resultType="Product">
        select * from product where id in
        <foreach collection="array" item="id" index="i" open="(" close=")" separator=",">
            "${id}"
        </foreach>
    </select>

</mapper>

DAO层：

package com.item.dao;

import com.item.common.JDBC;
import com.item.mapper.ProductMapper;
import com.item.model.Product;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class ProduceDAO {
    /**
     * 多个查询
     * @param array (字符串id数组)
     * @return
     */
    public static List<Product> GetInfo(String []array) {
        SqlSessionFactory factory = JDBC.GetConn();
        SqlSession session = factory.openSession();
        ProductMapper db = session.getMapper(ProductMapper.class);
        List<Product> list = db.GetInfo(array);
        session.close();
        return list;
    }
}

参数传递：

package com.item.mapper;

import com.item.model.Product;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface ProductMapper {
    List<Product> GetInfo(@Param("array") String[] array);
}

测试类： 

package com.item.action;

import com.item.dao.ProduceDAO;
import com.item.model.Product;

import java.util.List;

public class Action {
    public static void main(String[] args){
        String [] array={"b383581fd20211ec84b500e070bfdb54",
                "b3839547d20211ec84b500e070bfdb54",
                "b383d49dd20211ec84b500e070bfdb54",
                "b384180cd20211ec84b500e070bfdb54",
                "f6715eb2d20111ec84b500e070bfdb54"};
        List<Product> list = ProduceDAO.GetInfo(array);
        for (Product p : list) {
            System.out.println("编号"+p.getId());
            System.out.println("创建时间"+p.getCreateDate());
            System.out.println("修改时间"+p.getModifyDate());
            System.out.println("产品名称"+p.getProductName());
            System.out.println("产品标题"+p.getProductTitle());
            System.out.println("产品价格"+p.getProductPrice());
            System.out.println("产品数量"+p.getProductCount());
            System.out.println("品牌类型"+p.getProductType());
            System.out.println("重量"+p.getProductWeight());
            System.out.println("状态"+(p.getProductStatus()==1?"上架":"下架"));
        }
    }
}

查询结果：

循环的用处可以很多可以进行批量添加、修改、删除等处。