用 Apache Derby 进行开发 —— 取得节节胜利: 用 Apache Derby 进行 Java 数据库开发，第 6 部分

                
public class Product {
    
    private int itemNumber = 0 ;
    private BigDecimal price = null ;
    private Date stockDate = null ;
    private String description = null ;
    
    public Product(int itemNumber, BigDecimal price, Date stockDate, String description){
        this.itemNumber = itemNumber ;
        this.price = price ;
        this.stockDate = stockDate ;
        this.description = description ;
    }

    public void printProduct() {
        String line = "------------------------------------" ;
        
        System.out.println("\nBigdog's Surf Shop Product Information") ;
        System.out.println(line + line);
        
        System.out.printf("Item Number      : %-11s\n", this.itemNumber) ;
        System.out.printf("Item Price       : $%-8.2f\n", this.price) ;
        System.out.printf("Item StockDate   : %-10s\n", this.stockDate) ;
        System.out.printf("Item Description : %-40s\n", this.description) ;
        
        System.out.println(line + line + "\n");
    }
...

                
SELECT itemNumber, price, stockDate, description " + 
        "FROM bigdog.products WHERE itemNumber = ?" ;
...
    public Product getProduct(int targetItemNumber){

        Product product = null ;

        try{
            pstmt.clearParameters() ;
            pstmt.setInt(1, targetItemNumber) ;

            ResultSet rs = pstmt.executeQuery();

            if (rs.next()) {
                int itemNumber = rs.getInt("itemNumber") ;
                BigDecimal price = rs.getBigDecimal("price") ;
                Date stockDate = rs.getDate("stockDate") ;
                String description = rs.getString("description") ;

                product = new Product(itemNumber, price, stockDate, description) ;
            }
            
            rs.close() ;
            
        } catch(SQLException se) {
            printSQLException(se) ;
        }

        return product;
    }
...

                
public class DBManager {
    private static Connection con = null ;    

    private static final String driver = "org.apache.derby.jdbc.EmbeddedDriver" ;
    private static final String url = "jdbc:derby:" ;
    private static final String dbName = "SurfShop" ;
...
    private ProductDAO pdao = null ;

    public DBManager(){
        if(!dbExists()){
            try {
                Class.forName(driver) ;
                con = DriverManager.getConnection(url + dbName + ";create=true");

                processStatement(createProductsSQL) ;

                con.setAutoCommit(false) ;
                batchInsertData(insertProductsSQL) ;
                con.commit() ;

            }catch(BatchUpdateException bue) {
...
            }
        }
        pdao = new ProductDAO(con) ;
    }

    public void close() {
        try {
            con = DriverManager.getConnection(url + ";shutdown=true") ;
        }catch(SQLException se) {
            ; // Do Nothing. System has shut down.
        }
        con = null ;
    }

    public ProductDAO getProductDAO() {
        return pdao ;
    }

    private Boolean dbExists() {
        Boolean exists = false ;
        try{
            Class.forName(driver) ;
            con = DriverManager.getConnection(url + dbName);
            exists = true ;
        } catch(Exception e){
            ; // Do nothing, as DB does not (yet) exist
        }
        return(exists) ;
    }
...

                
import java.io.BufferedReader ;
import java.io.InputStreamReader ;

public class DemoApp {
    private DBManager dbm = null ;
    private ProductDAO pdao = null ;
    private int maxItemNumber = 0 ;

    public DemoApp() {
        this.dbm = new DBManager() ;
        this.pdao = dbm.getProductDAO() ;
        this.maxItemNumber = pdao.getMaxItemNumber() ;
    }

    public void showProduct() {

        int itemNumber = 0 ;
        Product p = null ;

        BufferedReader cin = new BufferedReader(new InputStreamReader(System.in)) ;

        while(true) {
            try {
                System.out.print("Enter object item number (0 to Exit): ") ;
                itemNumber = Integer.parseInt(cin.readLine()) ;
            }catch(Exception ex){
                ; // Do nothing. In this simple demo you ignore any input errors.
            }    
            
            if(itemNumber == 0)
                break ;
            else if ((itemNumber < 0) || (itemNumber > this.maxItemNumber))
                System.out.println ("Invalid product item number, please try again.") ;
            else{
                p = pdao.getProduct(itemNumber) ;
                p.printProduct() ;
            }
        }
        dbm.close() ;
    }

    public static void main(String[] args) {
        DemoApp da = new DemoApp() ;
        da.showProduct() ;
    }
}

                
rb$ mkdir derbyWork
rb$ cd derbyWork/
rb$ unzip ../derby14.zip 
Archive:  ../derby14.zip
  inflating: DBManager.java          
  inflating: DemoApp.java            
  inflating: Product.java            
  inflating: ProductDAO.java         
  inflating: manifest.txt  
rb$ more manifest.txt 
Main-Class: DemoApp
Class-Path: lib/derby.jar

rb$

                
rb$ mkdir lib
rb$ cp $DERBY_INSTALL/lib/derby.jar lib/
rb$ javac *.java
rb$ jar cvmf manifest.txt demoapp.jar *.class
added manifest
adding: DBManager.class(in = 5087) (out= 2792)(deflated 45%)
adding: DemoApp.class(in = 1460) (out= 881)(deflated 39%)
adding: Product.class(in = 1684) (out= 919)(deflated 45%)
adding: ProductDAO.class(in = 2625) (out= 1369)(deflated 47%)
rb$ ls
DBManager.class         Product.class           demoapp.jar
DBManager.java          Product.java            lib
DemoApp.class           ProductDAO.class        manifest.txt
DemoApp.java            ProductDAO.java
rb$ rm -rf *.java *.class manifest.txt 
rb$ ls
demoapp.jar     lib
rb$ zip demoapp.zip demoapp.jar lib/derby.jar 
  adding: demoapp.jar (deflated 6%)
  adding: lib/derby.jar (deflated 8%)
rb$ rm -rf demoapp.jar lib 
rb$ ls
demoapp.zip

                
rb$ unzip demoapp.zip 
Archive:  demoapp.zip
  inflating: demoapp.jar             
   creating: lib/
rb$ rm demoapp.zip 
rb$ CLASSPATH=  
rb$ export CLASSPATH
rb$ echo $CLASSPATH

rb$ java -jar demoapp.jar 
Enter object item number (0 to Exit): -1
Invalid product item number, please try again.
Enter object item number (0 to Exit): 11
Invalid product item number, please try again.
Enter object item number (0 to Exit): 1

Bigdog's Surf Shop Product Information
------------------------------------------------------------------------
Item Number      : 1          
Item Price       : $19.94   
Item StockDate   : 2006-03-31
Item Description : Hooded sweatshirt                       
------------------------------------------------------------------------

Enter object item number (0 to Exit): 10

Bigdog's Surf Shop Product Information
------------------------------------------------------------------------
Item Number      : 10         
Item Price       : $34.95   
Item StockDate   : 2006-01-24
Item Description : Open-toed sandal                        
------------------------------------------------------------------------

Enter object item number (0 to Exit): 0
rb$ ls
SurfShop        demoapp.jar     derby.log       lib