JDBC练习

完成商品品牌数据的增删改查

查询：查询所有数据

添加：添加品牌

修改：根据id修改

删除：根据id删除

1、数据表tb_brand的创建

CREATE table tb_brand
(

//id主键
id int  primary key auto_increment,

//品牌名称
brand_name varchar(20),

//企业名称
company_name varchar(20),

//排序字段
ordered int,

//描述信息
description varchar(100),

//状态：0：禁用  1：启用
status  int
);


INSERT into tb_brand(brand_name,company_name,ordered,description,status)
value('三只松鼠','三只索尼概述股份有限公司',5 ,'好吃不上火',0 ),
('华为','华为技术有限公司',100 ,'华为致力于，。。。。',0 ),
('小米','小米科技有限公司',50 ,'areuok',1 );
select * from tb_brand

2、实体类的创建

int尽量使用封装数据类型integer，防止默认值0对业务产生影响

alter+鼠标左键

可以实现多列同时编辑

package com.avb.pojo;

public class Brand {
    //id主键
    private Integer id                       ;

    //品牌名称
    private String brand_name                   ;

    //企业名称
    private String company_name                 ;

//排序字段
    private Integer ordered;

    //描述信息
    private String description                  ;

//状态：0：禁用  1：启用
    private Integer status                       ;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getBrand_name() {
        return brand_name;
    }

    public void setBrand_name(String brand_name) {
        this.brand_name = brand_name;
    }

    public String getCompany_name() {
        return company_name;
    }

    public void setCompany_name(String company_name) {
        this.company_name = company_name;
    }

    public Integer getOrdered() {
        return ordered;
    }

    public void setOrdered(Integer ordered) {
        this.ordered = ordered;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    @Override
    public String toString() {
        return "Brand{" +
                "id=" + id +
                ", brand_name='" + brand_name + '\'' +
                ", company_name='" + company_name + '\'' +
                ", ordered=" + ordered +
                ", description='" + description + '\'' +
                ", status=" + status +
                '}';
    }
}

3、实现查询所有

package com.avb.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.avb.pojo.Brand;
import org.junit.jupiter.api.Test;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

/*brand类的增删改查操作*/
public class brand_test {
    @Test
    public void testSelectALl() throws Exception{
        //1、导入jar包

        //2、配置文件

        //3、加载配置文件
        Properties prop = new Properties();
        prop.load(new FileInputStream("src/druid.properties"));
        //4、获取数据库连接Connection
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5、获取数据库连接Connection
        Connection conn= dataSource.getConnection();
        //System.out.println(conn);
        //6、构建sql语句
        String sql="select * from tb_brand";
        //创建stmt对象
        PreparedStatement pstmt = conn.prepareStatement(sql) ;
        //设置参数

        //执行sql
        ResultSet rs = pstmt.executeQuery();
        //处理结果 List<Brand> 封装Brand对象，装载List集合
        Brand brand = null;
        List<Brand> brands = new ArrayList<>();
        while (rs.next()){
            //获取数据 alter+enter可以自动补全
            int id = rs.getInt("id");
            String brandName = rs.getString("brand_name");
            String companyName = rs.getString("company_name");
            int ordered = rs.getInt("ordered");
            String description = rs.getString("description");
            int status = rs.getInt("status");
            /*System.out.println(id);
            System.out.println(brandName);
            System.out.println(companyName);
            System.out.println(ordered);
            System.out.println(status);
            System.out.println(description);
*/
            //封装brand对象
            brand = new Brand();
            brand.setId(id);
            brand.setBrand_name(brandName);
            brand.setCompany_name(companyName);
            brand.setOrdered(ordered);
            brand.setDescription(description);
            brand.setStatus(status);
            //装载集合
            brands.add(brand);
        }
        System.out.println(brands);
        //释放资源
        pstmt.close();
        conn.close();
        rs.close();
        //System.out.println(System.getProperty("user.dir"));
    }

}

4、添加数据

@Test
    public void testAdd() throws Exception{
        //1、导入jar包

        //2、配置文件

        //3、加载配置文件
        Properties prop = new Properties();
        prop.load(new FileInputStream("src/druid.properties"));
        //4、获取数据库连接Connection
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5、获取数据库连接Connection
        Connection conn= dataSource.getConnection();
        //System.out.println(conn);
        //定义插入数据
        String brandName = "香飘飘奶茶";
        String companyName = "香飘飘";
        int ordered = 8;
        String description = "可绕地球三圈";
        int status = 1;
        //6、构建sql语句
        String sql="insert into tb_brand(brand_name,company_name,ordered,description,status) value(?,?,?,?,?)";
        //创建pstmt对象
        PreparedStatement pstmt = conn.prepareStatement(sql) ;
        //设置参数
        pstmt.setString(1,brandName);
        pstmt.setString(2,companyName);
        pstmt.setInt(3,ordered);
        pstmt.setString(4,description);
        pstmt.setInt(5,status);
        //执行sql
        int count = pstmt.executeUpdate();
        //处理结果 List<Brand> 封装Brand对象，装载List集合
        /*Brand brand = null;
        List<Brand> brands = new ArrayList<>();
        while (rs.next()){
            //获取数据 alter+enter可以自动补全
            int id = rs.getInt("id");
            String brandName = rs.getString("brand_name");
            String companyName = rs.getString("company_name");
            int ordered = rs.getInt("ordered");
            String description = rs.getString("description");
            int status = rs.getInt("status");*/
            /*System.out.println(id);
            System.out.println(brandName);
            System.out.println(companyName);
            System.out.println(ordered);
            System.out.println(status);
            System.out.println(description);
*/
            //封装brand对象
           /* brand = new Brand();
            brand.setId(id);
            brand.setBrand_name(brandName);
            brand.setCompany_name(companyName);
            brand.setOrdered(ordered);
            brand.setDescription(description);
            brand.setStatus(status);
            //装载集合
            brands.add(brand);
        }
            System.out.println(brands);*/
        //判断结果
        System.out.println(count>0);
        //释放资源
        pstmt.close();
        conn.close();
        //rs.close();
        //System.out.println(System.getProperty("user.dir"));
    }

5、修改数据

@Test
    public void testupdate() throws Exception{
        //1、导入jar包

        //2、配置文件

        //3、加载配置文件
        Properties prop = new Properties();
        prop.load(new FileInputStream("src/druid.properties"));
        //4、获取数据库连接Connection
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5、获取数据库连接Connection
        Connection conn= dataSource.getConnection();
        //System.out.println(conn);
        //定义插入数据
        String brandName = "香飘飘奶茶";
        String companyName = "香飘飘";
        int ordered = 2;
        String description = "可绕地球六圈";
        int status = 0;
        int id = 4;
        //6、构建sql语句
        String sql="update tb_brand set brand_name = ?,company_name = ?,ordered = ?,description=?,status=? where id=?";
        //创建pstmt对象
        PreparedStatement pstmt = conn.prepareStatement(sql) ;
        //设置参数
        pstmt.setString(1,brandName);
        pstmt.setString(2,companyName);
        pstmt.setInt(3,ordered);
        pstmt.setString(4,description);
        pstmt.setInt(5,status);
        pstmt.setInt(6,id);
        //执行sql
        int count = pstmt.executeUpdate();
        //处理结果 List<Brand> 封装Brand对象，装载List集合
        /*Brand brand = null;
        List<Brand> brands = new ArrayList<>();
        while (rs.next()){
            //获取数据 alter+enter可以自动补全
            int id = rs.getInt("id");
            String brandName = rs.getString("brand_name");
            String companyName = rs.getString("company_name");
            int ordered = rs.getInt("ordered");
            String description = rs.getString("description");
            int status = rs.getInt("status");*/
            /*System.out.println(id);
            System.out.println(brandName);
            System.out.println(companyName);
            System.out.println(ordered);
            System.out.println(status);
            System.out.println(description);
*/
        //封装brand对象
           /* brand = new Brand();
            brand.setId(id);
            brand.setBrand_name(brandName);
            brand.setCompany_name(companyName);
            brand.setOrdered(ordered);
            brand.setDescription(description);
            brand.setStatus(status);
            //装载集合
            brands.add(brand);
        }
            System.out.println(brands);*/
        //判断结果
        System.out.println(count>0);
        //释放资源
        pstmt.close();
        conn.close();
        //rs.close();
        //System.out.println(System.getProperty("user.dir"));
    }

}

6、删除数据

 @Test
    public void testdeletebyid() throws Exception{
        //1、导入jar包

        //2、配置文件

        //3、加载配置文件
        Properties prop = new Properties();
        prop.load(new FileInputStream("src/druid.properties"));
        //4、获取数据库连接Connection
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5、获取数据库连接Connection
        Connection conn= dataSource.getConnection();
        //System.out.println(conn);
        //定义插入数据
        int id = 4;
        //6、构建sql语句
        String sql="delete from tb_brand where id = ?";
        //创建pstmt对象
        PreparedStatement pstmt = conn.prepareStatement(sql) ;
        //设置参数
        pstmt.setInt(1,id);
        //执行sql
        int count = pstmt.executeUpdate();
        //判断结果
        System.out.println(count>0);
        //释放资源
        pstmt.close();
        conn.close();
        //rs.close();
        //System.out.println(System.getProperty("user.dir"));
    }