Smelly JDBC Code

Attention.md

Smelly JDBC Code (Java)

Employee.java

public class Employee {
  private final Integer id;
  private final String name;
  
  public Employee(final Integer id, final String name) {
    this.id = id;
    this.name = name;
  }
  public String toString() { 
    return String.format("Employee(%d, %s)", id, name); 
  }
}

Sql.java

import java.sql.*;
import java.util.*;

public class Sql {
  static List<Employee> execute(String dburl, String sql) throws SQLException {
    Connection connection = null;
    Statement statement = null;
    ResultSet resultSet = null;
    List<Employee> employees = new ArrayList<Employee>();
    try {
      connection = DriverManager.getConnection(dburl);
      statement = connection.createStatement();
      statement.execute(sql);
      resultSet = statement.getResultSet();
      while (resultSet.next()) {
        int empId = resultSet.getInt(0);
        String name = resultSet.getString(1); 
        employees.add(new Employee(empId, name));
      }
    } catch (SQLException e) { 
      e.printStackTrace(); 
    } finally {
      if (connection != null) {
        connection.close();
        if (statement != null) {
          statement.close();
          if (resultSet != null)
            resultSet.close();
        }
      }
    }
    return employees;    
  }
  
  public static void main(String args[]) throws ClassNotFoundException {
    try {
      Class.forName("com.mysql.jdbc.Driver");
      String url = "jdbc:mysql://localhost:3306/test";
      List<Employee> employees  = Sql.execute(url,"select * from employee");
      System.out.println("employees = " + employees);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}