JDBC practice cases

demand

Environmental preparation

1. Database table tb_brand

--  Delete tb_brand surface 
drop table if exists tb_brand;
--  establish tb_brand surface 
create table tb_brand (
    -- id  Primary key 
    id int primary key auto_increment,
    --  The brand name 
    brand_name varchar(20),
    --  Company name 
    company_name varchar(20),
    --  Sort field 
    ordered int,
    --  Description information 
    description varchar(100),
    --  state ：0： Ban   1： Enable 
    status int
);
--  Add data 
insert into tb_brand (brand_name, company_name, ordered, description, status)
values (' The three little squirrels ', ' Three squirrels Co., Ltd ', 5, ' It's delicious but not hot ', 0),
       (' Huawei ', ' Huawei Technology Co., Ltd ', 100, ' Huawei is committed to bringing the digital world to everyone 、 Every family 、 Every organization , Building an intelligent world of interconnection of all things ', 1),
       (' millet ', ' Xiaomi Technology Co., Ltd ', 50, 'are you ok', 1);

2. stay pojo Package entity classes Brand

/** *  brand  * alt +  Left mouse button ： Edit the entire column  *  In entity classes , For basic data types, it is recommended to use their corresponding packaging types  */
public class Brand {
    
    // id  Primary key 
    private Integer id;
    //  The brand name 
    private String brandName;
    //  Company name 
    private String companyName;
    //  Sort field 
    private Integer ordered;
    //  Description information 
    private String description;
    //  state ：0： Ban  1： Enable 
    private Integer status;

    public Integer getId() {
    
        return id;
    }

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

    public String getBrandName() {
    
        return brandName;
    }

    public void setBrandName(String brandName) {
    
        this.brandName = brandName;
    }

    public String getCompanyName() {
    
        return companyName;
    }

    public void setCompanyName(String companyName) {
    
        this.companyName = companyName;
    }

    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 +
                ", brandName='" + brandName + '\'' +
                ", companyName='" + companyName + '\'' +
                ", ordered=" + ordered +
                ", description='" + description + '\'' +
                ", status=" + status +
                '}';
    }
}

JDBC operation

1. Query all

/** * Druid Database connection pool demo  */
public class DruidDemo {
    
    public  static void fun() throws  Exception {
    

        //1.  obtain Connection
        //3.  Load profile 
        Properties prop = new Properties();
        prop.load(new FileInputStream("jdbc-demo/src/druid.properties"));
        //4.  Get connection pool object 
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);

        //5.  Get database connection  Connection
        Connection conn = dataSource.getConnection();
        //2.  Definition SQL
        String sql = "select * from tb_brand;";
        //3.  obtain pstmt object 
        PreparedStatement pstmt = conn.prepareStatement(sql);
        //4.  Set parameters 
        //5.  perform SQL
        ResultSet rs = pstmt.executeQuery();
        //6.  Processing results  List<Brand>  encapsulation Brand object , load List aggregate 
        Brand brand = null;
        List<Brand> brands = new ArrayList<>();
        while (rs.next()){
    
            // get data 
            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");
            // encapsulation Brand object 
            brand = new Brand();
            brand.setId(id);
            brand.setBrandName(brandName);
            brand.setCompanyName(companyName);
            brand.setOrdered(ordered);
            brand.setDescription(description);
            brand.setStatus(status);

            // Load collection 
            brands.add(brand);
        }
        System.out.println(brands);
        //7.  Release resources 
        rs.close();
        pstmt.close();
        conn.close();

    }
    public static void main(String[] args) throws Exception {
    
        fun();
    }
}

2. Add data

/** * Druid Database connection pool demo  */
public class DruidDemo {
    
    public  static void fun() throws  Exception {
    
//  Receive the parameters submitted by the page 
        String brandName = " Fragrant ";
        String companyName = " Fragrant ";
        int ordered = 1;
        String description = " Circle the earth ";
        int status = 1;

        //1.  obtain Connection
        //3.  Load profile 
        Properties prop = new Properties();
        prop.load(new FileInputStream("jdbc-demo/src/druid.properties"));
        //4.  Get connection pool object 
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5.  Get database connection  Connection
        Connection conn = dataSource.getConnection();
        //2.  Definition SQL
        String sql = "insert into tb_brand(brand_name, company_name, ordered, description, status) values(?,?,?,?,?);";
        //3.  obtain pstmt object 
        PreparedStatement pstmt = conn.prepareStatement(sql);
        //4.  Set parameters 
        pstmt.setString(1,brandName);
        pstmt.setString(2,companyName);
        pstmt.setInt(3,ordered);
        pstmt.setString(4,description);
        pstmt.setInt(5,status);

        //5.  perform SQL
        int count = pstmt.executeUpdate(); //  Number of rows affected 
        //6.  Processing results 
        System.out.println(count > 0);

        //7.  Release resources 
        pstmt.close();
        conn.close();
    }
    public static void main(String[] args) throws Exception {
    
        fun();
    }

3. Modifying data

public class DruidDemo {
    
    public  static void fun() throws  Exception {
    

        //  Receive the parameters submitted by the page 
        String brandName = " Fragrant ";
        String companyName = " Fragrant ";
        int ordered = 1000;
        String description = " Three circles around the earth ";
        int status = 1;
        int id = 4;

        //1.  obtain Connection
        //3.  Load profile 
        Properties prop = new Properties();
        prop.load(new FileInputStream("jdbc-demo/src/druid.properties"));
        //4.  Get connection pool object 
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5.  Get database connection  Connection
        Connection conn = dataSource.getConnection();
        //2.  Definition SQL
        String sql = " update tb_brand\n" +
                " set brand_name = ?,\n" +
                " company_name= ?,\n" +
                " ordered = ?,\n" +
                " description = ?,\n" +
                " status = ?\n" +
                " where id = ?";

        //3.  obtain pstmt object 
        PreparedStatement pstmt = conn.prepareStatement(sql);

        //4.  Set parameters 
        pstmt.setString(1,brandName);
        pstmt.setString(2,companyName);
        pstmt.setInt(3,ordered);
        pstmt.setString(4,description);
        pstmt.setInt(5,status);
        pstmt.setInt(6,id);

        //5.  perform SQL
        int count = pstmt.executeUpdate(); //  Number of rows affected 
        //6.  Processing results 
        System.out.println(count > 0);

        //7.  Release resources 
        pstmt.close();
        conn.close();

    }
    public static void main(String[] args) throws Exception {
    
        fun();
    }
}

4. Delete data

public class DruidDemo {
    
    public  static void fun() throws  Exception {
    

        //  Receive the parameters submitted by the page 
        int id = 4;
        //1.  obtain Connection
        //3.  Load profile 
        Properties prop = new Properties();
        prop.load(new FileInputStream("jdbc-demo/src/druid.properties"));
        //4.  Get connection pool object 
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //5.  Get database connection  Connection
        Connection conn = dataSource.getConnection();
        //2.  Definition SQL
        String sql = " delete from tb_brand where id = ?";
        //3.  obtain pstmt object 
        PreparedStatement pstmt = conn.prepareStatement(sql);
        //4.  Set parameters 
        pstmt.setInt(1,id);
        //5.  perform SQL
        int count = pstmt.executeUpdate(); //  Number of rows affected 
        //6.  Processing results 
        System.out.println(count > 0);

        //7.  Release resources 
        pstmt.close();
        conn.close();

    }
    public static void main(String[] args) throws Exception {
    
        fun();
    }
}