openfire(3)数据库浅析
openfire 中的连接有几种，可以自己实现接口ConnectionProvider，修改openfire.xml中的connectionProvider的属性为自己实现的类。
<connectionProvider>
??? <className>org.jivesoftware.database.DefaultConnectionProvider</className>
? </connectionProvider>
? <database>
??? <defaultProvider>
????? <driver>com.mysql.jdbc.Driver</driver>
????? <serverURL>jdbc:mysql://localhost:3306/openfire?useUnicode=true&amp;characterEncoding=UTF-8&amp;zeroDateTimeBehavior=convertToNull</serverURL>
????? <username>root</username>
????? <password>admin</password>
????? <testSQL>select 1</testSQL>
????? <testBeforeUse>false</testBeforeUse>
????? <testAfterUse>false</testAfterUse>
????? <minConnections>5</minConnections>
????? <maxConnections>25</maxConnections>
????? <connectionTimeout>1.0</connectionTimeout>
??? </defaultProvider>
? </database>
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openfire实现了3个相关的接口，JNDIDataSourceProvider，EmbeddedConnectionProvider，DefaultConnectionProvider（默认的连接管理器），下面将分别解析这三个类。
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1. DefaultConnectionProvider：是openfire提供的默认连接管理器，使用了org.logicalcobwebs.proxool.ProxoolDriver提供的连接池，
其中ConnectionProvider的start方法如下，主要设置连接池的相关参数
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?public void start() {
??????? proxoolURL = "proxool.openfire:"+getDriver()+":"+getServerURL();
??????? settings = new Properties();
??????? settings.setProperty("proxool.maximum-activetime", Integer.toString(activeTimeout));
??????? settings.setProperty("proxool.maximum-connection-count", Integer.toString(getMaxConnections()));
??????? settings.setProperty("proxool.minimum-connection-count", Integer.toString(getMinConnections()));
??????? settings.setProperty("proxool.maximum-connection-lifetime", Integer.toString((int)(86400000 * getConnectionTimeout())));
??????? settings.setProperty("proxool.test-before-use", testBeforeUse.toString());
??????? settings.setProperty("proxool.test-after-use", testAfterUse.toString());
??????? settings.setProperty("proxool.house-keeping-test-sql", testSQL);
??????? settings.setProperty("user", getUsername());
??????? settings.setProperty("password", (getPassword() != null ? getPassword() : ""));
??? }
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2.EmbeddedConnectionProvider（嵌入式连接管理器），主要是用于openfire中采用的hsqldb.
? public Connection getConnection() throws SQLException {
??????? try {
??????????? Class.forName("org.logicalcobwebs.proxool.ProxoolDriver");
??????????? return DriverManager.getConnection(proxoolURL, settings);
??????? }
??????? catch (ClassNotFoundException e) {
??????????? throw new SQLException("EmbeddedConnectionProvider: Unable to find driver: "+e);
??????? }
??? }
，此也采用org.logicalcobwebs.proxool.ProxoolDriver代理连接池。
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hsqldb，的存放地址为openfire目录下的embedded-db中。
? File databaseDir = new File(JiveGlobals.getHomeDirectory(), File.separator + "embedded-db");
??????? // If the database doesn't exist, create it.
??????? if (!databaseDir.exists()) {
??????????? databaseDir.mkdirs();
??????? }
??????? try {
??????????? serverURL = "jdbc:hsqldb:" + databaseDir.getCanonicalPath() + File.separator + "openfire";
??????? }
??????? catch (IOException ioe) {
??????????? Log.error("EmbeddedConnectionProvider: Error starting connection pool: ", ioe);
??????? }
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Hsqldb是一个开放源代码的JAVA数据库，其具有标准的SQL语法和JAVA接口，它可以自由使用和分发，非常简洁和快速的。具有Server模式，进程内模式(In-Process)和内存模式(Memory-Only)三种。运行Hsqldb需要hsqldb.jar包, 它包含了一些组件和程序。每个程序需要不同的命令来运行。
更多关于Hsqldb请查看其它相关资料，在openfire中使用的标准的sql。
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3.JNDIDataSourceProvider
openfire提供的JNDI连接器。
?public void start() {
??????? if (dataSourceName == null || dataSourceName.equals("")) {
??????????? Log.error("No name specified for DataSource. JNDI lookup will fail", new Throwable());
??????????? return;
??????? }
??????? try {
??????????? Properties contextProperties = new Properties();
??????????? for (String key: jndiPropertyKeys) {
??????????????? String value = JiveGlobals.getXMLProperty(key);
??????????????? if (value != null) {
??????????????????? contextProperties.setProperty(key, value);
??????????????? }
??????????? }
??????????? Context context;
??????????? if (contextProperties.size() > 0) {
??????????????? context = new InitialContext(contextProperties);
??????????? }
??????????? else {
??????????????? context = new InitialContext();
??????????? }
??????????? dataSource = (DataSource)context.lookup(dataSourceName);
??????? }
??????? catch (Exception e) {
??????????? Log.error("Could not lookup DataSource at '" + dataSourceName + "'", e);
??????? }
??? }
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其主要属性有：
?private static final String[] jndiPropertyKeys = {
??????? Context.APPLET,
??????? Context.AUTHORITATIVE,
??????? Context.BATCHSIZE,
??????? Context.DNS_URL,
??????? Context.INITIAL_CONTEXT_FACTORY,
??????? Context.LANGUAGE,
??????? Context.OBJECT_FACTORIES,
??????? Context.PROVIDER_URL,
??????? Context.REFERRAL,
??????? Context.SECURITY_AUTHENTICATION,
??????? Context.SECURITY_CREDENTIALS,
??????? Context.SECURITY_PRINCIPAL,
??????? Context.SECURITY_PROTOCOL,
??????? Context.STATE_FACTORIES,
??????? Context.URL_PKG_PREFIXES
??? };
具体可查看JNDI相关。
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4.实现自己的连机器（ConnectionProvider），
public interface ConnectionProvider {
??? public boolean isPooled();
???
??? public Connection getConnection() throws SQLException;
???
??? public void start();
???
??? public void restart();
??? public void destroy();
}
需要写以上相关方法，可以用通用的连接池，c3p0,阿帕奇的dbcp等。
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对于openfire比较遗憾的是，没有相关事务的管理，关于sql的处理在各个模块都有，耦合性较大。
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此篇文章就到此，稍后会有更多关于openfire的个人解读。
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