jdbc 教程

JDBC
链接数据库

利用反射机制查看包是否被导入，idea可以用maven导入依赖，
Class.forName(“com.mysql.cj.jdbc.Driver”);
maven代码如下：

        
            mysql
            mysql-connector-java
            8.0.25
            runtime
        

粘贴到pom.xml里面然后导入一下。

这里设置链接地址 jdbc:mysql://127.0.0.1代表链接本机，3306是端口号，supermaket 数据库名 ，characterEncoding = UTF-8编码格式
String url = “jdbc:mysql://127.0.0.1:3306/supermaket?characterEncoding = UTF-8”;
建立链接
Connection conn = DriverManager.getConnection(url, “root”, “11”);

public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入用户名");
        String uName = scanner.next();
        System.out.println("请输入密码");
        String uTel = scanner.next();
        try{
            Class.forName("com.mysql.cj.jdbc.Driver");
            String url = "jdbc:mysql://127.0.0.1:3306/supermaket?characterEncoding = UTF-8";
            Connection conn = DriverManager.getConnection(url, "root", "11");
           // String sql = "insert into user values(null,'蒲林之',0,'123')";
            String sql1 = "select * from user where uName ='"+uName+"'and tel='"+uTel+"'";
            Statement statement = conn.createStatement();
           // int i = statement.executeUpdate(sql);
            ResultSet resultSet = statement.executeQuery(sql1);
            resultSet.next();
            int anInt = resultSet.getInt(1);
            if (anInt>0){
                String name = resultSet.getString(2);
                System.out.println("欢迎您"+name);
            }else {
                System.out.println("登录失败");
            }

            // System.out.println(i);
            statement.close();
            conn.close();
        }catch (Exception e){
            System.out.println("程序错误");
        }
    }