JDBC练习

查询所有数据

 准备环境:
数据库表tb_brand

实体类Brand
测试用例

public class test {
    
    public void test() throws Exception {
        //获取连接
        Properties prop =new Properties();
        prop.load(new FileInputStream("D:/IdeaProject/jdbcdmo/src/druid.properties"));
//        4．获取数据库连接池对象
        DataSource dataSource= DruidDataSourceFactory.createDataSource(prop);
//        5．获取连接
        Connection conn=dataSource.getConnection();
        //2.定义SQL
        String sql="select * from tb_brand;";
        //3.获取ptmt对象
        java.sql.PreparedStatement pstmt= conn.prepareStatement(sql);
//        PreparedStatement pstmt= (PreparedStatement) conn.prepareStatement(sql);
       //4.设置参数，这里不需要
        //5.执行SQl
        ResultSet rs=pstmt.executeQuery();
        //6.处理结果 List,封装brand 对象，装载List集合
        brand brander=null;
        List brands=new ArrayList<>();
        while (rs.next()){
            //获取数据
            int id=rs.getInt(1);
            String brand =rs.getString(2);
            String companyname=rs.getString(3);
            int order=rs.getInt(4);
            String desc= rs.getString(5);
            String status=rs.getString(6);
            //封装对象
            brander.setId(id);
            brander.setBrand_name(brand);
            brander.setCompany_name(companyname);
            brander.setOrdered(order);
            brander.setDescription(desc);
            brander.setStatus(status);
            //装载集合
            brands.add(brander);
        }
        //7.释放对象
        rs.close();
        pstmt.close();
        conn.close();
    }
}

添加

public class test {
    
    public void test() throws Exception {
        String brandname="香飘飘";
        String companyname="香飘飘";
        int order=1;
        String description="好喝";
        String status="卖出";
        //获取连接
        Properties prop =new Properties();
        prop.load(new FileInputStream("D:/IdeaProject/jdbcdmo/src/druid.properties"));
//        4．获取数据库连接池对象
        DataSource dataSource= DruidDataSourceFactory.createDataSource(prop);
      //        1．获取连接
        Connection conn=dataSource.getConnection();
        //2.定义SQL
        String sql="insert into tb_brand(brand_name,company_name,order,description,status)value(?,?,?,?,?)";
        //3.获取ptmt对象
        PreparedStatement pstmt= (PreparedStatement) conn.prepareStatement(sql);

       //4.设置参数
        pstmt.setString(1,brandname);
        pstmt.setString(2,companyname);
        pstmt.setInt(3,order);
        pstmt.setString(4,description);
        pstmt.setString(5,status);

        //5.执行SQl
        int cout=pstmt.executeUpdate();

        //6处理结果
        System.out.print(cout);

        //7.释放对象
        pstmt.close();
        conn.close();
    }
}