今天重新學習了JDBC連線資料庫，使用的資料庫是Oracle，在執行前已經手動建立了一張t_user表，建表資訊如下：

create table t_user(

       card_id number(19) primary key,

       password varchar2(6),

       balance number(20,3),

       phone varchar2(12)

);

考慮到手機號不會參加數值運算，所以將其型別設定為varchar

Java方面主要為了將來在實際開發中可能會用到，所以儘可能寫的比較完善，使用者登入部分和後臺插入部分基本已經寫好

方法寫得比較集中，實際開發中可能會把獲取使用者輸入值的部分單獨寫在主方法裡

查詢方法和插入方法也會做成帶布林型別返回值的方法

import java.util.*;

import java.sql.*;

public class User {

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

//        login();

        add();

        }

    public static void login() throws Exception{

        //0.獲取使用者輸入值

        @SuppressWarnings("resource")

        Scanner input = new Scanner(System.in);

        System.out.println("Please enter card id: ");

        String c = input.next();

        System.out.println("Please enter password: ");

        String p = input.next();

        String pass = new String();

        //1.載入驅動

        Class.forName("oracle.jdbc.OracleDriver");

        //2.獲得資料庫連線

        String url = "jdbc:oracle:thin:@127.0.0.1:1521:XE";

        String user = "hr";

        String password = "hr";

        Connection conn = DriverManager.getConnection(url,user,password);

        System.out.println(conn);

        //3.準備SQL語句

        String insertSQL = "select * from t_accounts "

                + "where card_id = " + c;

        System.out.println(insertSQL);

        //4.傳送SQL語句

        Statement stm = conn.createStatement();//獲得傳送SQL的物件

        ResultSet rs = stm.executeQuery(insertSQL);//傳送查詢SQL

        //5.處理ResultSet結果集

        while(rs.next()){

            //迴圈的指向所有行資料

            String passw = rs.getString("password");

            pass = passw;

        }

        //6.釋放資源

        rs.close();

        stm.close();

        conn.close();

        System.out.println(pass);

        //7.判斷使用者輸入值是否正確並作輸出

        if(Integer.parseInt(pass) == Integer.parseInt(p))

            System.out.println("Login success");

        else

            System.out.println("Login fail, please try again");

    }

    public static void add() throws Exception{

        //0.獲取使用者輸入值

        @SuppressWarnings("resource")

        Scanner input = new Scanner(System.in);

        System.out.println("Please enter card id: ");

        String c = input.next();

        System.out.println("Please enter password: ");

        String p = input.next();

        System.out.println("Please enter balance: ");

        double b = input.nextDouble();

        System.out.println("Please enter phone: ");

        String ph = input.next();

        //1.載入驅動

        Class.forName("oracle.jdbc.OracleDriver");

        //2.獲得資料庫連線

        String url = "jdbc:oracle:thin:@127.0.0.1:1521:XE";

        String user = "hr";

        String password = "hr";

        Connection conn = DriverManager.getConnection(url,user,password);

        System.out.println(conn);

        //3.準備SQL語句

        String insertSQL = "insert into t_accounts(card_id, password, balance, phoe) values("+c+", '"+p+"', "+b+", '"+ph+"')";

        //4.傳送SQL語句

        Statement stm = conn.createStatement();//獲得傳送SQL的物件

        int i = stm.executeUpdate(insertSQL);//傳送SQl（傳送增刪改）

        System.out.println(i);

        //5.釋放資源

        stm.close();

        conn.close();

        //6.判斷修改是否成功

        if(i != 0)

            System.out.println("Add success");

        else

            System.out.println("Add fail");

    }

}

控制檯輸出：

Please enter card id:

100003

Please enter password:

123456

Please enter balance:

100000

Please enter phone:

13007516785

oracle.jdbc.driver.T4CConnection@6438a396

1

Add success