自写的连接池-生产者消费者

public class DBConnectionPool
{
    // 默认的最大线程数阀值
    private static final int DEFAULT_MAX = 10;
    
    // 默认的最小线程数阀值
    private static final int DEFAULT_MIN = 5;
    
    // 默认的最长等待时间
    private static final long DEFAULT_MAXWAIT = 10000L;
    
    // 最大线程数阀值
    private int max;
    
    // 最先线程数阀值
    private int min;
    
    // 最长等待时间
    private long maxWait;
    
    // 当前请求获取连接数
    private int currentRequest;
    
    // 当前激活数
    private int currentActive;
    
    // 池
    private List<Connection> pool;
    
    // 连接源
    private Entry source;
    
    public DBConnectionPool(String driverName, String url, String userName, String password)
    {
        this(DEFAULT_MAX, DEFAULT_MIN, DEFAULT_MAXWAIT, driverName, url, userName, password);
    }
    
    public DBConnectionPool(int max, int min, long maxWait, String driverName, String url, String userName,
        String password)
    {
        pool = new LinkedList<Connection>();
        source = new Entry(driverName, url, userName, password);
        this.max = max;
        this.min = min;
        this.maxWait = maxWait;
        this.addPool(pool);
    }
    
    // 获取连接
    public synchronized Connection getConnection()
    {
        currentRequest++;
        System.out.println("currentRequest: " + currentRequest);
        Connection con = null;
        beginTransaction(maxWait);
        if (pool.size() == 0)
        {
            try
            {
                con = source.getConnection();
                currentActive++;
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
        else if (pool.size() < min)
        {
            con = pool.remove(0);
            System.out.println("12312312");
            currentActive++;
        }
        else
        {
            con = pool.remove(0);
            currentActive++;
        }
        System.out.println("currentActive : " + currentActive);
        return con;
    }
    
    // 判断是否超过最大数，超过等待，没有超过就唤醒
    private void beginTransaction(long maxWait)
    {
        if (currentRequest > max)
        {
            try
            {
                if (maxWait > 0)
                    this.wait(maxWait);
                else
                {
                    this.wait(DEFAULT_MAXWAIT);
                }
                if (currentRequest > max)
                {
                    throw new RuntimeException("获取连接超时");
                }
                else
                {
                    System.out.println("等待之后获取了连接");
                }
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
        }
        else
        {
            this.notifyAll();
        }
    }

// 注入源
    private void addPool(List<Connection> pool)
    {
        for (int i = pool.size(); i < min; i++)
        {
            try
            {
                pool.add(source.getConnection());
            }
            catch (Exception e)
            {
                e.printStackTrace();
                continue;
            }
        }
    }
    
    // 关闭连接
    public synchronized void close(Connection con)
    {
        if (con != null)
        {
            currentRequest--;
            System.out.println("currentRequest: " + currentRequest);
            beginTransaction(maxWait);
            if (pool.size() < max)
            {
                pool.add(con);
            }
            else
            {
                try
                {
                    con.close();
                }
                catch (SQLException e)
                {
                    e.printStackTrace();
                }
                finally
                {
                    con = null;
                }
            }
            currentActive--;
            System.out.println("currentActive : " + currentActive);
        }
    }
    
    // 连接获取实体类
    private static class Entry
    {
        private String driverName;
        
        private String url;
        
        private String userName;
        
        private String password;
        
        public Entry(String driverName, String url, String userName, String password)
        {
            super();
            this.driverName = driverName;
            this.url = url;
            this.userName = userName;
            this.password = password;
        }
        
        Connection getConnection()
            throws Exception
        {
            Class.forName(driverName);
            return DriverManager.getConnection(url, userName, password);
        }
    }
}