今、http://commons.apache.org/dbcp/[Apache DBCP]は活発な開発に戻っており、多くのバグは修正されており、現在はより安定しています。 Hibernateでも、http://docs.jboss.org/hibernate/core/3.6/javadocs/org/hibernate/connection/C3P0ConnectionProvider.html[C3P0]やhttp://docs.jboss.orgのような接続プロバイダは付属していません/hibernate/core/3.6/javadocs/org/hibernate/connection/ProxoolConnectionProvider.html[Proxool]でも簡単に設定できます。

このチュートリアルでは、Apache DBCP接続プールとHibernateフレームワークを統合する方法を説明します。

1. DBCP jarを取得する

DBCPとHibernateを統合するには、

commons-dbcp.jar



commons-pool-1.5.4.jar

が必要です。


File:pom.xml

<project ...>

    <repositories>
        <repository>
            <id>JBoss repository</id>
            <url>http://repository.jboss.org/nexus/content/groups/public/</url>
        </repository>
    </repositories>

    <dependencies>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>3.6.3.Final</version>
        </dependency>

        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.4</version>
        </dependency>

    </dependencies>
</project>

2. DBCPConnectionProvider

DBCPとHibernateを統合するには、 ”

DBCPConnectionProvider

“クラスを作成する必要があります。このクラスはhttp://wiki.apache.org/commons/DBCP/Hibernate[articleを参照してください。

ファイル:DBCP Connection Provider.java

package com.mkyong.util;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.dbcp.BasicDataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;
import org.hibernate.HibernateException;
import org.hibernate.cfg.Environment;
import org.hibernate.connection.ConnectionProvider;
import org.hibernate.connection.ConnectionProviderFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DBCPConnectionProvider implements ConnectionProvider {

    private static final Logger log = LoggerFactory
            .getLogger(DBCPConnectionProvider.class);
    private static final String PREFIX = "hibernate.dbcp.";
    private BasicDataSource ds;

   //Old Environment property for backward-compatibility (property removed in
   //Hibernate3)
    private static final String DBCP__PS__MAXACTIVE = "hibernate.dbcp.ps.maxActive";

   //Property doesn't exists in Hibernate2
    private static final String AUTOCOMMIT = "hibernate.connection.autocommit";

    public void configure(Properties props) throws HibernateException {
        try {
            log.debug("Configure DBCPConnectionProvider");

           //DBCP properties used to create the BasicDataSource
            Properties dbcpProperties = new Properties();

           //DriverClass & url
            String jdbcDriverClass = props.getProperty(Environment.DRIVER);
            String jdbcUrl = props.getProperty(Environment.URL);
            dbcpProperties.put("driverClassName", jdbcDriverClass);
            dbcpProperties.put("url", jdbcUrl);

           //Username/password
            String username = props.getProperty(Environment.USER);
            String password = props.getProperty(Environment.PASS);
            dbcpProperties.put("username", username);
            dbcpProperties.put("password", password);

           //Isolation level
            String isolationLevel = props.getProperty(Environment.ISOLATION);
            if ((isolationLevel != null)
                    && (isolationLevel.trim().length() > 0)) {
                dbcpProperties.put("defaultTransactionIsolation",
                        isolationLevel);
            }

           //Turn off autocommit (unless autocommit property is set)
            String autocommit = props.getProperty(AUTOCOMMIT);
            if ((autocommit != null) && (autocommit.trim().length() > 0)) {
                dbcpProperties.put("defaultAutoCommit", autocommit);
            } else {
                dbcpProperties.put("defaultAutoCommit",
                        String.valueOf(Boolean.FALSE));
            }

           //Pool size
            String poolSize = props.getProperty(Environment.POOL__SIZE);
            if ((poolSize != null) && (poolSize.trim().length() > 0)
                    && (Integer.parseInt(poolSize) > 0)) {
                dbcpProperties.put("maxActive", poolSize);
            }

           //Copy all "driver" properties into "connectionProperties"
            Properties driverProps = ConnectionProviderFactory
                    .getConnectionProperties(props);
            if (driverProps.size() > 0) {
                StringBuffer connectionProperties = new StringBuffer();
                for (Iterator iter = driverProps.entrySet().iterator(); iter
                        .hasNext();) {
                    Map.Entry entry = (Map.Entry) iter.next();
                    String key = (String) entry.getKey();
                    String value = (String) entry.getValue();
                    connectionProperties.append(key).append('=').append(value);
                    if (iter.hasNext()) {
                        connectionProperties.append(';');
                    }
                }
                dbcpProperties.put("connectionProperties",
                        connectionProperties.toString());
            }

           //Copy all DBCP properties removing the prefix
            for (Iterator iter = props.entrySet().iterator(); iter.hasNext();) {
                Map.Entry entry = (Map.Entry) iter.next();
                String key = (String) entry.getKey();
                if (key.startsWith(PREFIX)) {
                    String property = key.substring(PREFIX.length());
                    String value = (String) entry.getValue();
                    dbcpProperties.put(property, value);
                }
            }

           //Backward-compatibility
            if (props.getProperty(DBCP__PS__MAXACTIVE) != null) {
                dbcpProperties.put("poolPreparedStatements",
                        String.valueOf(Boolean.TRUE));
                dbcpProperties.put("maxOpenPreparedStatements",
                        props.getProperty(DBCP__PS__MAXACTIVE));
            }

           //Some debug info
            if (log.isDebugEnabled()) {
                StringWriter sw = new StringWriter();
                dbcpProperties.list(new PrintWriter(sw, true));
                log.debug(sw.toString());
            }

           //Let the factory create the pool
            ds = (BasicDataSource) BasicDataSourceFactory
                    .createDataSource(dbcpProperties);

           //The BasicDataSource has lazy initialization
           //borrowing a connection will start the DataSource
           //and make sure it is configured correctly.
            Connection conn = ds.getConnection();
            conn.close();

           //Log pool statistics before continuing.
            logStatistics();
        } catch (Exception e) {
            String message = "Could not create a DBCP pool";
            log.error(message, e);
            if (ds != null) {
                try {
                    ds.close();
                } catch (Exception e2) {
                   //ignore
                }
                ds = null;
            }
            throw new HibernateException(message, e);
        }
        log.debug("Configure DBCPConnectionProvider complete");
    }

    public Connection getConnection() throws SQLException {
        Connection conn = null;
        try {
            conn = ds.getConnection();
        } finally {
            logStatistics();
        }
        return conn;
    }

    public void closeConnection(Connection conn) throws SQLException {
        try {
            conn.close();
        } finally {
            logStatistics();
        }
    }

    public void close() throws HibernateException {
        log.debug("Close DBCPConnectionProvider");
        logStatistics();
        try {
            if (ds != null) {
                ds.close();
                ds = null;
            } else {
                log.warn("Cannot close DBCP pool (not initialized)");
            }
        } catch (Exception e) {
            throw new HibernateException("Could not close DBCP pool", e);
        }
        log.debug("Close DBCPConnectionProvider complete");
    }

    protected void logStatistics() {
        if (log.isInfoEnabled()) {
            log.info("active: " + ds.getNumActive() + " (max: "
                    + ds.getMaxActive() + ")   " + "idle: " + ds.getNumIdle()
                    + "(max: " + ds.getMaxIdle() + ")");
        }
    }

    public boolean supportsAggressiveRelease() {
        return false;
    }
}

3. hibernate.cfg.xmlにDBCPを設定する

ここで、 ”

DBCPConnectionProvider

“をリンクし、 ”

hibernate.cfg.xml

“にDBCPプロパティを定義します。


File:hibernate.cfg.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 <session-factory>
  <property name="hibernate.connection.driver__class">oracle.jdbc.driver.OracleDriver</property>
  <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:MKYONG</property>
  <property name="hibernate.connection.username">mkyong</property>
  <property name="hibernate.connection.password">password</property>
  <property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>
  <property name="hibernate.default__schema">MKYONG</property>
  <property name="show__sql">true</property>

  <property name="hibernate.connection.provider__class">
    com.mkyong.util.DBCPConnectionProvider
  </property>
  <property name="hibernate.dbcp.initialSize">8</property>
  <property name="hibernate.dbcp.maxActive">20</property>
  <property name="hibernate.dbcp.maxIdle">20</property>
  <property name="hibernate.dbcp.minIdle">0</property>

  <mapping class="com.mkyong.user.DBUser"></mapping>
</session-factory>
</hibernate-configuration>

  • 注意

    DBCPプロパティは、Hibernateで ”

    hibernate.dbcp.properties-name ** “を介してサポートされています。

すべてのDBCPプロパティについては、http://commons.apache.org/dbcp/configuration.html[DBCP設定]ページを参照してください。

4.それを実行し、出力します.

完了して、次の出力を参照してください。


hibernateのdbcp接続プール、title = "hibernate-dbcp-connection-pool"、width = 639、height = 466

アプリケーションの起動段階では、8つのデータベース接続が接続プールに作成され、Webアプリケーションで使用できる状態になります。

それをダウンロードしてください://wp-content/uploads/2011/04/Hibernate-DBCP-Connection-Pool-Example.zip[Hibernate-DBCP-Connection-Pool-Example.zip](10KB)