reademployeerecords.java

来自「java 完全探索的随书源码」· Java 代码 · 共 94 行

import java.sql.*;

public class ReadEmployeeRecords
{
  // Private reference to an instance of the Connection
  private Connection conn = null;

  // Default Constructor
  public ReadEmployeeRecords( Connection connection )
  {
    conn = connection;
  }

  // Public method to read all of the records for the employees
  public void readRecords()
  {
    // SQL Statement to get all of the employees
    String READ_EMPLOYEE_SQL_STMT = "SELECT * FROM EMP";
    Statement stmt = null;
    ResultSet rs = null;

    try
    {
      stmt = getConnection().createStatement();
      stmt.execute( READ_EMPLOYEE_SQL_STMT );
      rs = stmt.getResultSet();
    }
    catch( SQLException ex )
    {
      ex.printStackTrace();
    }

    // Call the public method to print the employees out
    printEmployeeRecords( rs );
  }

  // Private accessor for the connection
  private Connection getConnection()
  {
    return conn;
  }

  // Use the ResultSet and print the records to the console
  public void printEmployeeRecords( ResultSet rs )
  {
    try
    {
      // While there are more records to read from the ResultSet
      while( rs.next() )
      {
        // Get the data by using the column index from the table.
        // Could also have used the column names like
        // rs.getString( "firstName" );
        //
        String nbr = rs.getString( 1 );
        String name = rs.getString( 2 );
        String job = rs.getString( 3 );
        String mgr = rs.getString( 4 );
        Timestamp hireDate = rs.getTimestamp(5);

        Employee employee = new Employee( nbr, name, job, mgr, hireDate );

        System.out.println( employee.toString() );
      }
    }
    catch( SQLException ex )
    {
      ex.printStackTrace();
    }
  }

  // Method to start this class and test the examples
  public static void main(String[] args)
  {
    // Use the previous DatabaseManager
    Connection conn = DatabaseManager.getConnection();
    ReadEmployeeRecords reader = new ReadEmployeeRecords( conn );
    reader.readRecords();

    // Always make sure to close the connection when you are finished
    try
    {
      conn.close();
    }
    catch( SQLException ex )
    {
      ex.printStackTrace();
    }
    catch( Exception ex )
    {
      ex.printStackTrace();
    }
  }
}