Java开发网 - 求一个比较好用的数据库连接池组件

Topic: 求一个比较好用的数据库连接池组件

1.求一个比较好用的数据库连接池组件	Copy to clipboard
Posted by: jfml Posted on: 2003-04-18 11:04 谢谢

2.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jfml Posted on: 2003-04-18 12:05 不要太庞大的谢谢

3.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: DesertApple Posted on: 2003-04-18 13:25 IBM java Developer 专区有教程，自己参照做一个吧~

4.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jfml Posted on: 2003-04-18 13:26 那里的文章只是简单地介绍一下而已

5.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]

Copy to clipboard

Posted by: yung
Posted on: 2003-04-18 15:42

File: DBConnectionManager.java:

package beans;

/**
* @author
*
*/

import java.util.Vector;
import java.util.Enumeration;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ResourceBundle;
import java.util.MissingResourceException;

/**
* Database Connection Manager
*/
public class DBConnectionManager {

private static final String OPTION_FILE_NAME = "DBOptions";
private final static DBConnectionManager instance=new DBConnectionManager();
private DBConnectionPool pool;

/**
* Use singleton pattern, only return one instance of DBConnectionManager.
* 取得 DBConnectionManager 实例的唯一方式
* @return DBConnectionManager
*/
public static DBConnectionManager getInstance() {
return instance;
}
/**
* Get a connection
* @return Connection
*/
public Connection getConnection() throws SQLException{
return pool.getConnection();
}
/**
* Free a connection
* @param con connection
* @throws SQLException this method
*/
public void freeConnection(Connection con) throws SQLException{
pool.freeConnection(con);

}

private DBConnectionManager() {
init();
}

private void init() {
String db_driver = "";
String db_url = "";
String db_user = "";
String db_password = "";
int db_maxConn=0;

try {
ResourceBundle res = ResourceBundle.getBundle(OPTION_FILE_NAME);
db_driver = res.getString("DB_DRIVER").trim();
db_url = res.getString("DB_URL").trim();
db_user = res.getString("DB_USER").trim();
db_password = res.getString("DB_PASSWORD").trim();
db_maxConn = Integer.parseInt(res.getString("DB_MAX_CONNECTIONS"));

Class.forName(db_driver);
pool = new DBConnectionPool(db_url,db_user,db_password,db_maxConn);
} catch (Exception ex) {
System.out.println(ex);
}
System.out.println("ConnectionPool Init OK ! " +
"URL : "+ db_url +
", User : " + db_user +
", MaxConn : " + db_maxConn);
}

/**
* Closes all open connections.
*/
public void release() {
pool.release();
}

public String toString() {
return pool.toString();
}
/************************************************************************************
************************************************************************************/
// inner class

class DBConnectionPool {

private Vector freeConnections = new Vector();
private int maxConn;
private int connNumb;

private String URL;
private String user;
private String password;

public DBConnectionPool(String URL, String user, String password,int maxConn) {
this.URL = URL;
this.user = user;
this.password = password;
this.maxConn = maxConn;
}

public synchronized void freeConnection(Connection con) {
freeConnections.addElement(con);
connNumb--;
notifyAll(); // useful??
}

public synchronized Connection getConnection() throws SQLException{
Connection con = null;
if (freeConnections.size() > 0) {
con = (Connection) freeConnections.firstElement();
freeConnections.removeElementAt(0);
try {
if (con.isClosed()) {
con = getConnection();
}
}
catch (SQLException e) {
con = getConnection();
}
}
else if (maxConn == 0 || connNumb < maxConn) {
con = newConnection();
}
if (con != null) {
connNumb++;
}
return con;
}

private Connection newConnection() throws SQLException{
Connection con =DriverManager.getConnection(URL,user, password);
return con;
}

synchronized void release() {
Enumeration allConnections = freeConnections.elements();
while (allConnections.hasMoreElements()) {
Connection con = (Connection) allConnections.nextElement();
try {
con.close();
} catch (SQLException e) {
System.out.println("Can't close connection in DBConnectionPool.");
}
}
freeConnections.removeAllElements();
}

public synchronized String toString() {
String info =
"ConnectionPool(" + URL + "," + user + ")" +
", totalConn =" + connNumb +
", freeConnetion=" + freeConnections.size() +
", max=" + maxConn;
return(info);
}
} /// Inner class End.

}///~
-------------------------------------------------------------------------------------------
DBOptions.properties:

DB_DRIVER = org.mysql......Driver
DB_URL = jdbc:mysql...........
DB_USER = yung
DB_PASSWORD = passwd
DB_MAX_CONNECTIONS = 20
-------------------------------------------------------------------------------------------
File Test.java: (测试一下）
package beans;

/**
* @author
*
* To change this generated comment edit the template variable "typecomment":
* Window>Preferences>Java>Templates.
* To enable and disable the creation of type comments go to
* Window>Preferences>Java>Code Generation.
*/

import java.sql.*;

public class Test {
  public static void main(String[] args) throws Exception {
    DBConnectionManager dbcm = DBConnectionManager.getInstance();

    dbcm.release();
    Connection conn = dbcm.getConnection();

    System.out.println(dbcm);

    Statement stmt = null;
    ResultSet rs = null;
    ResultSetMetaData md = null;

    try {
      stmt = conn.createStatement();
      rs = stmt.executeQuery("select * from users");
      md = rs.getMetaData();
      while (rs.next()) {
        for (int i = 1; i <= md.getColumnCount(); i++) {
          System.out.print(rs.getString Light Bulb

+ " | ");
        }
        System.out.println("");
      }
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      dbcm.freeConnection(conn);
      dbcm.freeConnection(conn1);
    }
    dbcm.release();
    System.out.println(dbcm);

  }
}

6.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jfml Posted on: 2003-04-18 18:12 上面这个程序一旦得８到连接就返回ＮＵＬＬ觉得不太好吧

7.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jeez Posted on: 2003-04-18 19:29 DBCP是Apache的一个项目，详细内容见http://jakarta.apache.org/commons/dbcp/index.html。

8.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: black1234 Posted on: 2003-04-18 19:31 楼上的组件容易在池中保留死连接。最好还是用server自带的。

9.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jfml Posted on: 2003-04-18 20:10 是这样的我做的是个大型的Ｓｗｉｎｇ　Ａｐｐｌｉｃａｔｉｏｎ不是Ｂ/S的阿想用个简单但又不能太差的连接池

10.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jeez Posted on: 2003-04-18 23:23 从Tomcat,Jboss等项目中扒吧。

11.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jfml Posted on: 2003-04-19 00:46 独立出来容易么？

12.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: rainman Posted on: 2003-04-19 02:55 如果是Swing程序就没必要用Connection Pool了，因为你不会弄几个并发线程去访问数据库吧？用一个保持数据库连接就可以了。如果断了再自动重新连一次。

13.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: jeez Posted on: 2003-04-19 20:46 像Tomcat,JBoss这类软件，架构一般都比较灵活，设计较好，也就是说比较独立的组件很容易剥离出来。

14.Re:求一个比较好用的数据库连接池组件 [Re: CrazyJavar]	Copy to clipboard
Posted by: harvshen Posted on: 2003-04-22 14:34 留下你的EMAIL, 我发一个给你.

15.Re:求一个比较好用的数据库连接池组件 [Re: black1234]	Copy to clipboard
Posted by: emarket Posted on: 2003-04-22 15:05 DBCP是tomcat缺省得 connection pool 我一直用它，很少，死连我也遇到过（连接MySQL），是因为 MySQL得问题，在ｕｒｌ中把加入autoReconnect=true就可以解决了