Java DB (Derby) 的使用(1)

The Embedded mode is limited by that we can't run simultaneously two programs (two JVM instances) using a same database (databaseName is the same).

But we can instead use the NetworkServer mode to avoid this case, it is to say the "Client/Server" mode. In this mode, you have to first start the NetworkServer by this command :

java org.apache.derby.drda.NetworkServerControl start [-h hostIP -p portNumber]

package com.han;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

/**
* The Embedded mode is limited by that we can't run simultaneously
* two programs (two JVM instances) using a same database (databaseName is the same).
* <p>
* But we can instead use the NetworkServer mode to avoid this case,
* it is to say the "Client/Server" mode.
* In this mode, you have to first start the NetworkServer by this command :
* <pre>
*java org.apache.derby.drda.NetworkServerControl start [-h hostIP -p portNumber]* </pre>
* @author HAN
*
*/
public class Derby {
private Connection con=null;
private String port=null;
private String ip=null;

/**
* The port will be set to default: 1527
*/
public void setPortToDefault(){
port="1527";
}

public void setPort(String port){
this.port=port;
}

public void setServer(String ip){
this.ip=ip;
}

/**
* This express loading driver is not necessary for Java 6 and later, JDBC 4.0 and later.
* Because it can be added automatically by <code>DriverManager</code> when connecting to a database.
*/
public void loadDriver(){
//load the driver
if(port==null){
try {
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
System.out.println("The embedded driver is successfully loaded");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{
try{
Class.forName("org.apache.derby.jdbc.ClientDriver");
System.out.println("The client driver is successfully loaded");
}catch(ClassNotFoundException e){
e.printStackTrace();
}
}
}

/**
* create and connect a database
* @param databaseName
* @param user
* @param password
* @return a connection to the URL
*/
public Connection createDatabaseAndGetConnection(String databaseName, String user, String password){
//create and connect the database
Properties props=new Properties();
props.put("user",user);
props.put("password",password);
if(port==null){
try {
con=DriverManager.getConnection("jdbc:derby:"+databaseName+";create=true", props);
System.out.println("Connection is successfully established, it use an Embedded database");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else if(ip==null){
try {
con=DriverManager.getConnection("jdbc:derby://localhost:"+port+"/"+databaseName+";create=true", props);
System.out.println("Connection is sucessfully established, it use an network database but stored in the local host via the port: "+port);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{
try {
con=DriverManager.getConnection("jdbc:derby://"+ip+":"+port+"/"+databaseName+";create=true", props);
System.out.println("Connection is sucessfully established, it use an network database whose host ip is: "+ip+"and via the port: "+port);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return con;
}

/**
* Shut down a specified database. But it doesn't matter that later we could also connect to another database.
* @param databaseName
*/
public void shutdownDatabase(String databaseName){
if(port==null){
try {
DriverManager.getConnection("jdbc:derby:"+databaseName+";shutdown=true");
} catch (SQLException e) {
// TODO Auto-generated catch block
System.out.println("Database: "+databaseName+" shut down normally");
}
}else if(ip==null){
try {
DriverManager.getConnection("jdbc:derby://localhost:"+port+"/"+databaseName+";shutdown=true");
} catch (SQLException e) {
// TODO Auto-generated catch block
System.out.println("Database: "+databaseName+" shut down normally");
}
}else{
try {
DriverManager.getConnection("jdbc:derby://"+ip+":"+port+"/"+databaseName+";shutdown=true");
} catch (SQLException e) {
// TODO Auto-generated catch block
System.out.println("Database: "+databaseName+" shut down normally");
}
}
}

/**
* shut down all opened databases and close the Derby driver.
* The effect is that after the execution of this method, we will not permitted to use Derby again in the rest of our program.
* Or else, an exception of "can't find a suitable driver for [a database URL]" will be thrown.
*/
public void shutdownAll(){
try {
DriverManager.getConnection("jdbc:derby:;shutdown=true");
} catch (SQLException e) {
// TODO Auto-generated catch block
System.out.println("All databases shut down normally and Derby driver closed");
}
}

/**
* Just connect to a database desired by providing the appropriate parameters.
* @param databaseName
* @param user
* @param password
* @return
*/
public Connection getConnection(String databaseName, String user, String password){
if(port==null){
try {
con=DriverManager.getConnection("jdbc:derby:"+databaseName,user,password);
System.out.println("Connection is sucessfully established, it use an Embedded database");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else if(ip==null){
try {
con=DriverManager.getConnection("jdbc:derby://localhost:"+port+"/"+databaseName,user,password);
System.out.println("Connection is sucessfully established, it use an network database but stored in the local host via the port: "+port);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{
try {
con=DriverManager.getConnection("jdbc:derby://"+ip+":"+port+"/"+databaseName,user,password);
System.out.println("Connection is sucessfully established, it use an network database whose host ip is: "+ip+"and via the port: "+port);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return con;
}
}

package com.han;

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

public class JavaDBUse1 {

static void createTable(Statement s) throws SQLException{
s.execute("create table table1(" +
"id char(6)," +
"name varchar(40)," +
"score int)");
s.execute("insert into table1 values('016954', 'San ZHANG', 86)");
s.execute("insert into table1 values('016934', 'Wu WANG', 45)");
s.execute("insert into table1 values('016908', 'Si LI', 97)");
}

public static void main(String[] args){
Derby derby=new Derby();
derby.loadDriver();
Connection con;
Statement s;

con=derby.getConnection("use1", "han", "");
try {
con.setAutoCommit(false);
s=con.createStatement();
ResultSet rs=s.executeQuery("select id, name, score from table1 order by score");
System.out.println("id\tname\tscore");
while(rs.next()){
StringBuilder sb=new StringBuilder(rs.getString("id"));
sb.append("\t");
sb.append(rs.getString("name"));
sb.append("\t");
sb.append(rs.getInt("score"));
System.out.println(sb.toString());
}
s.close();
System.out.println("closed statement");
con.commit();
con.close();
System.out.println("Committed transaction and closed connection");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
derby.shutdownDatabase("use1");
derby.shutdownAll();
}
}