MyBatis快速入门——第四章、mybatis动态sql_if_choose_when

DROP TABLE IF EXISTS `product`;
CREATE TABLE `product`  (
  `id` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `createDate` datetime(0) NOT NULL,
  `modifyDate` datetime(0) NOT NULL,
  `productName` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `productTitle` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `productPrice` decimal(10, 2) NOT NULL,
  `productCount` int(8) NOT NULL,
  `productType` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,
  `productColor` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `productWeight` double NULL DEFAULT NULL,
  `productStatus` int(1) NOT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
INSERT INTO `product` VALUES ('b383581fd20211ec84b500e070bfdb54', '2022-05-12 22:49:18', '2022-05-12 22:49:18', '外星人M15', '高端外星人', 13499.00, 299, '外星人', 'black', 3300, 1);
INSERT INTO `product` VALUES ('b3839547d20211ec84b500e070bfdb54', '2022-05-12 22:49:18', '2022-05-12 22:49:18', 'ThinkBook', '联想', 4599.00, 159, '联想', 'gray', 2250, 1);
INSERT INTO `product` VALUES ('b383d49dd20211ec84b500e070bfdb54', '2022-05-12 22:49:18', '2022-05-12 22:49:18', '戴尔G15', '戴尔', 7499.00, 179, '戴尔', 'gray', 2270, 1);
INSERT INTO `product` VALUES ('b384180cd20211ec84b500e070bfdb54', '2022-05-12 22:49:18', '2022-05-12 22:49:18', 'RedmiBook Pro15', '小米', 4499.00, 699, '小米', 'black', 2500, 1);
INSERT INTO `product` VALUES ('b38457bed20211ec84b500e070bfdb54', '2022-05-12 22:49:18', '2022-05-12 22:49:18', '华硕a豆', '华硕', 3699.00, 799, '华硕', 'pink', 2100, 1);
INSERT INTO `product` VALUES ('f6715eb2d20111ec84b500e070bfdb54', '2022-05-12 22:44:01', '2022-05-12 22:44:01', '拯救者Y7700P', '2022新品拯救者', 7399.00, 199, '联想', 'gray', 2200, 1);

<?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>
        <setting name="logImpl" value="LOG4J"/>
    </settings>
    <typeAliases>
        <package name="com.item.model"/>
    </typeAliases>
    <environments default="dev">
        <environment id="dev">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mytest?characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="12345678"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/item.mapper/ProductMapper.xml"></mapper>
    </mappers>
</configuration>

<?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
        <if test="productName!=null or productType!=null or productColor!=null ">
            where 1=1
        </if>
                <!-- 模糊查询 -->
                <if test="productName!=null">
                   and productName like "%${productName}%"
                </if>
                <!-- 类型筛选 -->
                <if test="productType!=null">
                    and productType="${productType}"
                </if>
                <!-- 颜色筛选 -->
                <if test="productColor!=null">
                    and productColor="${productColor}"
                </if>
    </select>
</mapper>

<?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
        <if test="productName!=null or productType!=null or productColor!=null ">
            where 1=1
        </if>
        <choose>
            <when test="productName!=null">
                and productName like "%${productName}%"
            </when>
            <when test="productType!=null">
                and productType = "${productType}"
            </when>
            <when test="productType!=null">
                and productColor = "${productColor}"
            </when>
        </choose>
    </select>
</mapper>

package com.item.common;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.Reader;
public class JDBC {
    public static SqlSessionFactory GetConn(){
        Reader reader = null;
        try {
            reader = Resources.getResourceAsReader("mybatis-config.xml");
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
            return factory;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

package com.item.model;
import java.math.BigDecimal;
import java.util.Date;
public class Product {
    private String id;
    private Date createDate;
    private Date modifyDate;
    private String productName;
    private String productTitle;
    private BigDecimal productPrice;
    private int productCount;
    private String productType;
    private String productColor;
    private double productWeight;
    private int productStatus;
    @Override
    public String toString() {
        return "Product{" +
                "id='" + id + '\'' +
                ", createDate=" + createDate +
                ", modifyDate=" + modifyDate +
                ", productName='" + productName + '\'' +
                ", productTitle='" + productTitle + '\'' +
                ", productPrice=" + productPrice +
                ", productCount=" + productCount +
                ", productType='" + productType + '\'' +
                ", productColor='" + productColor + '\'' +
                ", productWeight=" + productWeight +
                ", productStatus=" + productStatus +
                '}';
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public Date getCreateDate() {
        return createDate;
    }
    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }
    public Date getModifyDate() {
        return modifyDate;
    }
    public void setModifyDate(Date modifyDate) {
        this.modifyDate = modifyDate;
    }
    public String getProductName() {
        return productName;
    }
    public void setProductName(String productName) {
        this.productName = productName;
    }
    public String getProductTitle() {
        return productTitle;
    }
    public void setProductTitle(String productTitle) {
        this.productTitle = productTitle;
    }
    public BigDecimal getProductPrice() {
        return productPrice;
    }
    public void setProductPrice(BigDecimal productPrice) {
        this.productPrice = productPrice;
    }
    public int getProductCount() {
        return productCount;
    }
    public void setProductCount(int productCount) {
        this.productCount = productCount;
    }
    public String getProductType() {
        return productType;
    }
    public void setProductType(String productType) {
        this.productType = productType;
    }
    public String getProductColor() {
        return productColor;
    }
    public void setProductColor(String productColor) {
        this.productColor = productColor;
    }
    public double getProductWeight() {
        return productWeight;
    }
    public void setProductWeight(double productWeight) {
        this.productWeight = productWeight;
    }
    public int getProductStatus() {
        return productStatus;
    }
    public void setProductStatus(int productStatus) {
        this.productStatus = productStatus;
    }
}

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("productName") String productName,
                          @Param("productType") String productType,
                          @Param("productColor") String productColor);
}
ProduceDAO
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 {
    /**
     * 各类查询
     * @param productName (商品名称)
     * @param productType (商品类型)
     * @param productColor (商品颜色)
     * @return
     */
    public static List<Product> GetInfo(String productName,
                          String productType,
                          String productColor) {
        SqlSessionFactory factory = JDBC.GetConn();
        SqlSession session = factory.openSession();
        ProductMapper db = session.getMapper(ProductMapper.class);
        List<Product> list = db.GetInfo(productName, productType, productColor);
        session.close();
        return list;
    }
}

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){
        List<Product> list = ProduceDAO.GetInfo(null,"联想",null);
        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"));
        }
    }
}