connectionpool.java

此程序都是企业级 的数据库开发程序 全面揭示了JAVA对数据库的操作

package pooling;

import java.sql.*;
import java.util.*;

public class ConnectionPool {

  private Vector connections;
  private String url, username, password;
  private boolean inUse[];
  final private int poolsize = 10;

  // /////////////////////////////////////////////////////////////////
  // Name		ConnectionPool
  // Description	Constructor
  // /////////////////////////////////////////////////////////////////
  public ConnectionPool(String url, String username, 
                        String password) throws SQLException {
    this.url = url;
    this.username = username;
    this.password = password;
    connections = new Vector(poolsize);
    inUse = new boolean[poolsize];

    try {

      // Load the driver
      Class.forName("COM.cloudscape.core.JDBCDriver").newInstance();

      // Setup our pool of sources
      SetupConnectionsPool();
    } catch (Exception e) {
      e.printStackTrace();
    } 
  }

  // /////////////////////////////////////////////////////////////////
  // Name		SetupConnectonsPool
  // Description	Pre-Create our pool of connections
  // /////////////////////////////////////////////////////////////////
  private void SetupConnectionsPool() throws SQLException {
    for (int i = 0; i < poolsize; i++) {
      Connection conn = DriverManager.getConnection(url, username, 
              password);
      connections.addElement(conn);
      inUse[i] = false;
    } 
  } 

  // /////////////////////////////////////////////////////////////////
  // Name		freeConnection
  // Description	Release resource
  // /////////////////////////////////////////////////////////////////
  public void freeConnection(int connectionIdx) {
    inUse[connectionIdx] = false;
  } 

  // /////////////////////////////////////////////////////////////////
  // Name		getConnection
  // Description	Obtain a connection from the pool (if available)
  // /////////////////////////////////////////////////////////////////
  public Connection getConnection() {
    Connection c = null;
    for (int idx = 0; idx < connections.size(); idx++) {
      if (inUse[idx] == false) {
        c = (Connection) connections.elementAt(idx);
        inUse[idx] = true;
      } 
    } 
    return c;
  } 

  // /////////////////////////////////////////////////////////////////
  // Name		dumpConnectionStatus
  // Description	Dump the status of pool and connections
  // /////////////////////////////////////////////////////////////////
  public void dumpConnectionStatus() {
    System.out.println("\nConnection Pool Status");
    System.out.println("\nPool Size is " + connections.size());
    for (int i = 0; i < connections.size(); i++) {
      System.out.println("Pool Index [" + i + "] In Use status = " 
                         + inUse[i]);
    } 
  } 

}