clspublicmethods.java

《JBuilder编程技术与实例》（2006 四维科技 人民邮电）赠送代码——库存管理系统(Access)

package MainForm;

/*
********************************************************************************
*																			   *
* Note:																		   *
*      This is not intended to used in a big business because this system was  *
*      created for small business only.
* 																			   *
********************************************************************************
*/

import java.awt.*;
import java.sql.*;
import java.util.*;
import java.io.*;
import java.awt.PrintJob;
import javax.swing.*;

public class clsPublicMethods {

        public static boolean recordExist(String strSQL,Connection sCN){
                Statement stRE;
                ResultSet rsRE;
                int Total = 0;
                try{
                        stRE = sCN.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
                        rsRE = stRE.executeQuery(strSQL);
                        //Move to the last record
                        rsRE.afterLast();
                        //Get the current record position
                        if(rsRE.previous()){
                                Total = rsRE.getRow();
                        }else{
                                Total = 0;
                        }
                }catch(SQLException sqlEx){
                                System.out.println("\nERROR IN clsPublicMethods(recordExist):" + sqlEx + "\n");
                        }
                rsRE = null;
                stRE = null;
                if(Total == 0){
                        return false;
                }else{
                        return true;
                }
        }

        public static int getMaxNum(String strSQL,Connection sCN,String strFieldName){
                Statement stMaxRow;
                ResultSet rsMaxRow;
                int Max = 0;
                try{
                        stMaxRow = sCN.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
                        rsMaxRow = stMaxRow.executeQuery(strSQL);
                        //Move to the last record
                        rsMaxRow.afterLast();
                        //Get the current record position
                        if(rsMaxRow.previous()){
                                Max = rsMaxRow.getInt(strFieldName);
                        }else{
                                Max = 0;
                        }
                }catch(SQLException sqlEx){
                                System.out.println("\nERROR IN clsPublicMethods(getMaxNum):" + sqlEx + "\n");
                        }

                rsMaxRow = null;
                stMaxRow = null;
                return Max;
        }

        public static JComboBox fillCombo(String strSQL,Connection sCN,String strFieldName){
                Statement stFC;
                ResultSet rsFC;
                String cmbList[] =new String[0];
                int TotalRow = 0;
                int rowNum = 0;
                try{
                        stFC = sCN.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
                        rsFC = stFC.executeQuery(strSQL);
                        rsFC.afterLast();
                        //Get the current record position
                        if(rsFC.previous())TotalRow = rsFC.getRow();
                        //Move back to the first record;
                        rsFC.beforeFirst();
                        if(TotalRow > 0){
                                cmbList = new String[TotalRow];
                                while(rsFC.next()){
                                        cmbList[rowNum] = "" + rsFC.getString(strFieldName);
                                        rowNum++;
                                }
                        }else{
                                cmbList[0] ="";
                        }
                }catch(SQLException sqlEx){
                                System.out.println("\nERROR IN clsPublicMethods(fillCombo):" + sqlEx + "\n");
                        }
                rsFC = null;
                stFC = null;
                TotalRow=0;
                return new JComboBox(cmbList);
        }

        public void printRecord (String rec,JFrame JFMainParent) {

                StringReader SRReader = new StringReader (rec);
                LineNumberReader LNRReader = new LineNumberReader (SRReader);
                Font typeface = new Font ("Courier New", Font.PLAIN,10);
                PrintJob PJPrint = Toolkit.getDefaultToolkit().getPrintJob (JFMainParent, "", new Properties());

                if (PJPrint != null) {
                        Graphics GGraph = PJPrint.getGraphics ();
                        if (GGraph != null) {
                                FontMetrics FMFont = GGraph.getFontMetrics (typeface);
                                int PAGE_HEIGHT = PJPrint.getPageDimension().height - 75;
                                int FONT_HEIGHT = FMFont.getHeight();
                                int FONT_DESCENT = FMFont.getDescent();
                                int CURRENT_HEIGHT = 75;
                                String NEXT_LINE;
                                GGraph.setFont (typeface);

                                try {
                                        do {
                                                NEXT_LINE = LNRReader.readLine ();
                                                if (NEXT_LINE != null) {
                                                        if ((CURRENT_HEIGHT + FONT_HEIGHT) > PAGE_HEIGHT) {
                                                                GGraph.dispose();
                                                                GGraph = PJPrint.getGraphics ();
                                                                CURRENT_HEIGHT = 75;
                                                        }
                                                        CURRENT_HEIGHT += FONT_HEIGHT;
                                                        if (GGraph != null) {
                                                                GGraph.setFont (typeface);
                                                                GGraph.drawString (NEXT_LINE, 75, CURRENT_HEIGHT - FONT_DESCENT);
                                                        }
                                                }
                                        }
                                        while (NEXT_LINE != null);
                                }
                                catch (EOFException EOF_EXCEPTION) { }
                                catch (Throwable TROW_ERR) { }
                        }
                        GGraph.finalize();
                        GGraph.dispose();
                }
                if (PJPrint != null)
                        PJPrint.end ();
        }
}