Java의 데이터베이스 기술 및 데이터베이스 관리 기술

Connection conn = null;
try {
    Class.forName("com.mysql.cj.jdbc.Driver");
    String url = "jdbc:mysql://localhost:3306/test?serverTimezone=UTC";
    String user = "root";
    String password = "123456";
    conn = DriverManager.getConnection(url, user, password);
} catch (Exception e) {
    e.printStackTrace();
}

Statement stmt = null;
ResultSet rs = null;
try {
    stmt = conn.createStatement();
    String sql = "SELECT * FROM student";
    rs = stmt.executeQuery(sql);
    while(rs.next()) {
        System.out.println(rs.getString("name") + " " + rs.getInt("age"));
    }
} catch (Exception e) {
    e.printStackTrace();
}

CallableStatement cstmt = null;
try {
    String sql = "{call getStudentNum(?)}";
    cstmt = conn.prepareCall(sql);
    cstmt.registerOutParameter(1, Types.INTEGER);
    cstmt.execute();
    System.out.println(cstmt.getInt(1));
} catch (Exception e) {
    e.printStackTrace();
}

ResultSetMetaData rsmd = null;
try {
    stmt = conn.createStatement();
    String sql = "SELECT * FROM student";
    rs = stmt.executeQuery(sql);
    rsmd = rs.getMetaData();
    int columnCount = rsmd.getColumnCount();
    for (int i = 1; i <= columnCount; i++) {
        System.out.println(rsmd.getColumnName(i) + " " + rsmd.getColumnTypeName(i));
    }
} catch (Exception e) {
    e.printStackTrace();
}

public class Student {
    private String name;
    private int age;
    // getter and setter methods
}

PreparedStatement pstmt = null;
try {
    String sql = "INSERT INTO student(name, age) VALUES(?, ?)";
    pstmt = conn.prepareStatement(sql);
    pstmt.setString(1, "Tom");
    pstmt.setInt(2, 20);
    pstmt.executeUpdate();
} catch (Exception e) {
    e.printStackTrace();
}