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<html>
<head>
<title>Creating a Java application to access a Derby database</title>
</head>
<body>
<h2>Creating a Java application to access a Derby database</h2>
<p>
Once you've become familiar with starting the network server and running
SQL queries, you'll want to use Derby from within a Java application.
This section will demonstrate using Derby from a stand-alone Java
application.
</p>
<p>
This example will access the data in our sample database, <b>myDB</b>,
which contains the restaurants table. By following the two <a href="ij_toc.html"><b>ij</b></a> sections in the help, this database and table will have already
been created and ready to use. If you have not created the database and the table return to the <a href="ij_toc.html"><b>ij</b></a> sections and create them now.
</p>
<h3>Steps to create a stand-alone Java application</h3>
<ul>
<li>
From the <b>Java</b> perspective, select the project in the <b>Package Explorer</b> view. Right-click the project to bring up the context menu and select
<b>New, Class</b>.
</li>
</ul>
</p>
<img src="images/new_class.GIF" alt="Creating a Java class in Eclipse" width="914" height="638"></img>
<p>
Give the Java class a package name, <b>myapp</b>, name the class
<b>Restaurants</b>, make it a public class, and include a main method
in the class since this will be a stand-alone application. The image
below shows an example of this.
Click <b>Finish</b> to create the class.
</p>
<img src="images/create_class.GIF" alt="New Java class wizard" width="515" height="566"></img>
<p>
The Java class shown below, <b>Restaurants.java</b>, connects to the Derby Network Server, inserts a row into the restaurants table, and then displays a select
from the restaurants table. Copy the code below into the Java editor window
for the <b>Restaurants.java</b> class you just created.
</p>
<pre>
package myapp;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSetMetaData;
public class Restaurants
{
private static String dbURL = "jdbc:derby://localhost:1527/myDB;create=true;user=me;password=mine";
private static String tableName = "restaurants";
// jdbc Connection
private static Connection conn = null;
private static Statement stmt = null;
public static void main(String[] args)
{
createConnection();
insertRestaurants(5, "LaVals", "Berkeley");
selectRestaurants();
shutdown();
}
private static void createConnection()
{
try
{
Class.forName("org.apache.derby.jdbc.ClientDriver").newInstance();
//Get a connection
conn = DriverManager.getConnection(dbURL);
}
catch (Exception except)
{
except.printStackTrace();
}
}
private static void insertRestaurants(int id, String restName, String cityName)
{
try
{
stmt = conn.createStatement();
stmt.execute("insert into " + tableName + " values (" +
id + ",'" + restName + "','" + cityName +"')");
stmt.close();
}
catch (SQLException sqlExcept)
{
sqlExcept.printStackTrace();
}
}
private static void selectRestaurants()
{
try
{
stmt = conn.createStatement();
ResultSet results = stmt.executeQuery("select * from " + tableName);
ResultSetMetaData rsmd = results.getMetaData();
int numberCols = rsmd.getColumnCount();
for (int i=1; i<=numberCols; i++)
{
//print Column Names
System.out.print(rsmd.getColumnLabel(i)+"\t\t");
}
System.out.println("\n-------------------------------------------------");
while(results.next())
{
int id = results.getInt(1);
String restName = results.getString(2);
String cityName = results.getString(3);
System.out.println(id + "\t\t" + restName + "\t\t" + cityName);
}
results.close();
stmt.close();
}
catch (SQLException sqlExcept)
{
sqlExcept.printStackTrace();
}
}
private static void shutdown()
{
try
{
if (stmt != null)
{
stmt.close();
}
if (conn != null)
{
DriverManager.getConnection(dbURL + ";shutdown=true");
conn.close();
}
}
catch (SQLException sqlExcept)
{
}
}
}
</pre>
<p>
Once Restaurants.java is compiled without errors, run the Java application by
right-clicking it from the Package Explorer view and selecting <b>Run As, Java Application</b>.
</p>
<img src="images/run_javaapp.GIF" alt="Running a java application" width="857" height="703"></img>
<p>
The output from running <b>Restaurants.java</b> is shown below. It shows the
successful insert of a row into our restaurants table and a select of all rows
in the table. If you encounter any errors when running the application make
sure the Derby Network Server has been started on port 1527 and the myDB
database exists in the current workspace and Java project.
</p>
<img src="images/completed_javaapp.GIF" alt="Output from a java application" width="857" height="703"></img>
<h3>Changing the application to use the Derby Embedded Driver</h3>
<p>
<b>Restaurants.java</b> accessed the Derby database, <b>myDB</b> using
the Derby Network Client Driver. The values for loading the driver and the
Database connection URL are shown below.
</p>
<ul>
<li>
<b>
Driver name <br/>
</b>
org.apache.derby.jdbc.ClientDriver
<br/><br/>
</li>
<li>
<b>
Database connection URL<br/>
</b>
jdbc:derby://localhost:1527/myDB;create=true;user=me;password=mine
<br/><br/>
</li>
</ul>
<p>
To change the application to use the Derby Embedded Driver we need to change
these values to:
</p>
<ul>
<li>
<b>
Driver name <br/>
</b>
org.apache.derby.jdbc.EmbeddedDriver
<br/><br/>
</li>
<li>
<b>
Database connection URL<br/>
</b>
jdbc:derby:myDB;create=true;user=me;password=mine
<br/><br/>
</li>
</ul>
<h3>About Schema Names</h3>
<p>
If a database is created in Derby using the embedded driver and no user
name is specified, the default schema used becomes <b>APP</b>. Therefore
any tables created in the database have a schema name of <b>APP</b>.
However, when creating a Derby database using the Network Server, the value
for the schema becomes the value of the username used to connect with as
part of the database URL. In our example we first created the <b>myDB</b>
database using the user <b>me</b>.
</p>
<p>
When we change the application to connect using the embedded driver, the
schema will default to <b>APP</
derby_ui_plugin_1.1.2.zip （52个子文件） 
plugins org.apache.derby.ui_1.1.2 icons 
start.gif 881B add.gif 318B stop.gif 905B ij.gif 855B isrun.gif 67B sysinfo.gif 873B rem.gif 350B
LICENSE 11KB
ui.jar 39KB plugin.xml 17KB NOTICE 1KB org.apache.derby.plugin.doc_1.1.2 toc.xml 2KB LICENSE 11KB topics 
ij2.html 4KB sysinfo.html 2KB ij_toc.html 1KB resources.html 1KB nature.html 2KB java_project.html 2KB properties.html 4KB start_server.html 4KB start_toc.html 3KB nature_toc.html 2KB server_toc.html 2KB images properties.gif 35KB start_server_console.gif 30KB sysinfo_output.GIF 38KB new_class.GIF 40KB ij_commands.GIF 48KB create_class.GIF 21KB create_file.GIF 29KB shutdown_success.gif 33KB remove_nature.GIF 37KB stop_server.GIF 46KB property_sheet.GIF 20KB start_ij.GIF 46KB run_javaapp.GIF 52KB restaurant_script.GIF 47KB start_server.GIF 38KB sysinfo_start.GIF 41KB restaurant_editor.GIF 45KB stop_popup.gif 8KB create_restaurant.GIF 38KB server_popup.gif 7KB completed_javaapp.GIF 51KB add_nature.GIF 34KB derby_app.html 9KB ij.html 4KB stop_server.html 2KB remove_nature.html 2KB plugin.xml 1KB NOTICE 1KB资源评论
wym_fenger2014-10-11是的，可以使用，谢谢分享！- evil_sb2014-11-24与2013版的Eclipse不兼容,版本老了点
- jsntsunxixi2014-05-26可以使用，谢谢分享！
- dgyasheng2013-08-21不错，这正是我想要的。
- cy206251352013-06-14可以使用，谢谢分享！
