簡單的JDBC應用程式for Java DB

今天下載了jdk1.6.0,以後要慢慢來學習1.6中的新特性和其中的一些經典執行個體。先看看關於java DB的這個最簡例子：
Simple JDBC Application （源碼SimpleApp.java、文檔及derby.jar,derbynet.jar,derbyclient.ar檔案請從jdk1.6.0中找）

這個例子是一個最小限度的JDBC 應用程式。 關於這個程式：

• 以內嵌式模式（預設的）或作為一個伺服器環境中的用戶端運行，這依賴於傳遞給程式的參數
• 如果運行在內嵌式模式，則啟動Derby 引擎
• 如果運行在用戶端模式，則串連到 Derby 網路伺服器
• 建立並串連到資料庫
• 建立一個表
• 插入資料
• 更新資料
• 查詢資料
• 刪除表
• 關閉串連
• 如果運行在內嵌式模式，則關閉 Derby。

以下是源碼：

import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.Properties;/* * @author janet */public class SimpleApp{    /* 預設的模式是內嵌式的*/    public String framework = "embedded";    public String driver = "org.apache.derby.jdbc.EmbeddedDriver";    public String protocol = "jdbc:derby:";    public static void main(String[] args)    {        new SimpleApp().go(args);    }    void go(String[] args)    {        /* 處理參數，確定這個程式作為內嵌式使用還是作為用戶端使用*/        parseArguments(args);        System.out.println("SimpleApp starting in " + framework + " mode.");        try        {            /*               裝載驅動程式，如果是內嵌式模式，這將啟動Derby, 因為它還沒有運行.             */            Class.forName(driver).newInstance();            System.out.println("Loaded the appropriate driver.");            Connection conn = null;            Properties props = new Properties();            props.put("user", "user1");            props.put("password", "user1");            //create=true將建立資料庫derbyDB            conn = DriverManager.getConnection(protocol +"derbyDB;create=true", props);            System.out.println("Connected to and created database derbyDB");            conn.setAutoCommit(false);//設定自動認可模式            Statement s = conn.createStatement();            /*               建立一個表，加入幾條記錄並更新一條.             */            s.execute("create table derbyDB(num int, addr varchar(40))");            System.out.println("Created table derbyDB");            s.execute("insert into derbyDB values (1956,'Webster St.')");            System.out.println("Inserted 1956 Webster");            s.execute("insert into derbyDB values (1910,'Union St.')");            System.out.println("Inserted 1910 Union");            s.execute(                "update derbyDB set num=180, addr='Grand Ave.' where num=1956");            System.out.println("Updated 1956 Webster to 180 Grand");            s.execute(                "update derbyDB set num=300, addr='Lakeshore Ave.' where num=180");            System.out.println("Updated 180 Grand to 300 Lakeshore");            /*               查詢並校正結果.             */            ResultSet rs = s.executeQuery(                    "SELECT num, addr FROM derbyDB ORDER BY num");            if (!rs.next())            {                throw new Exception("Wrong number of rows");            }            if (rs.getInt(1) != 300)            {                throw new Exception("Wrong row returned");            }            if (!rs.next())            {                throw new Exception("Wrong number of rows");            }            if (rs.getInt(1) != 1910)            {                throw new Exception("Wrong row returned");            }            if (rs.next())            {                throw new Exception("Wrong number of rows");            }            System.out.println("Verified the rows");            s.execute("drop table derbyDB");//刪除表            System.out.println("Dropped table derbyDB");                       rs.close();            s.close();            System.out.println("Closed result set and statement");            conn.commit();            conn.close();            System.out.println("Committed transaction and closed connection");                       boolean gotSQLExc = false;            if (framework.equals("embedded"))            {                try                {                    DriverManager.getConnection("jdbc:derby:;shutdown=true");//關閉資料庫服務                }                catch (SQLException se)                {                    gotSQLExc = true;                }                if (!gotSQLExc)                {                    System.out.println("Database did not shut down normally");                }                else                {                    System.out.println("Database shut down normally");                }            }        }        catch (Throwable e)        {            System.out.println("exception thrown:");            if (e instanceof SQLException)            {                printSQLError((SQLException) e);            }            else            {                e.printStackTrace();            }        }        System.out.println("SimpleApp finished");    }    static void printSQLError(SQLException e)    {        while (e != null)        {            System.out.println(e.toString());            e = e.getNextException();        }    }    private void parseArguments(String[] args)    {       
        //  System.setProperty("derby.system.home", "c:\\DBdata");//這樣可以設定資料庫資料的存放目錄

        int length = args.length;        for (int index = 0; index < length; index++)        {            if (args[index].equalsIgnoreCase("jccjdbcclient"))            {                framework = "jccjdbc";                driver = "com.ibm.db2.jcc.DB2Driver";                protocol = "jdbc:derby:net://localhost:1527/";            }            if (args[index].equalsIgnoreCase("derbyclient"))            {                framework = "derbyclient";                driver = "org.apache.derby.jdbc.ClientDriver";                protocol = "jdbc:derby://localhost:1527/";            }        }    }}