lookupaction.java

电子时钟的java源程序

package ch03;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;

import ch08.WroxActionMapping;

public class LookupAction extends Action {

  protected Double getQuote(HttpServletRequest request, String symbol) {

    Double price = null;
    Connection conn = null;
    Statement stmt = null;
    ResultSet rs = null;
    DataSource dataSource = null;
    
    try {

      dataSource = getDataSource(request);
      conn = dataSource.getConnection();
      stmt = conn.createStatement();
      rs = stmt.executeQuery("select * from stocks where "
        + "symbol='" + symbol + "'");

      if ( rs.next() ) {

        double tmp = 0;
        tmp = rs.getDouble("price");

        price = new Double(tmp);

        System.err.println("price : "
          + price);
      }
      else {

        System.err.println("---->Symbol not found returning null<----");
      }
    }
    catch (SQLException e) {

      System.err.println(e.getMessage());
    }
    finally {

      if (rs != null) {

        try {

          rs.close();
        }
        catch (SQLException sqle) {

          System.err.println(sqle.getMessage());
        }
        rs = null;
      }
      if (stmt != null) {

        try {

          stmt.close();
        }
        catch (SQLException sqle) {

          System.err.println(sqle.getMessage());
        }
        stmt = null;
      }
      if (conn != null) {

        try {

          conn.close();
        }
        catch (SQLException sqle) {

          System.err.println(sqle.getMessage());
        }
        conn = null;
      }
    }
    return price;
  }

  /*
  protected Double getQuote(String symbol) {

    if ( symbol.equalsIgnoreCase("SUNW") ) {

      return new Double(25.00);
    }
    return null;
  }
  */
  
  public ActionForward execute(ActionMapping mapping,
    ActionForm form,
    HttpServletRequest request,
    HttpServletResponse response)
    throws IOException, ServletException {

    WroxActionMapping wroxMapping = (WroxActionMapping)mapping;

    Double price = null;
    String symbol = null;

    // Default target to success
    String target = new String("success");

    if ( form != null ) {

      LookupForm lookupForm = (LookupForm)form;

      symbol = lookupForm.getSymbol();

      price = getQuote(request, symbol);
    }
    
	  // if price is null, set the target to failure
    if ( price == null ) {

      target = new String("failure");
      
      ActionErrors errors = new ActionErrors();
      errors.add("symbol",
        new ActionError("errors.lookup.unknown",symbol));

      // Report any errors we have discovered
      if ( !errors.isEmpty() ) {

        saveErrors(request, errors);
      }
    }
    else {

      boolean logging = wroxMapping.getLogResults();
      if ( logging ) {

        System.err.println("SYMBOL:"
          + symbol + " PRICE:" + price);
      }

      request.setAttribute("PRICE", price);
    }
    // Forward to the appropriate View
    return (mapping.findForward(target));
  }
}