VoIP Knowledge Base sip-voip-completion Initial commit 202004291431HEADmaster

1 files changed, 392 insertions, 0 deletions

diff --git a/src/main/java/cn/ac/iie/dao/JdbcConnectionManager.java b/src/main/java/cn/ac/iie/dao/JdbcConnectionManager.java
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+package cn.ac.iie.dao;
+
+import java.io.FileNotFoundException;
+import java.io.InputStream;
+import java.sql.Connection;
+import java.sql.Driver;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Date;
+import java.util.Enumeration;
+import java.util.Hashtable;
+import java.util.Properties;
+import java.util.StringTokenizer;
+import java.util.Vector;
+
+import com.nis.exception.DaoException;
+
+
+
+
+
+/**
+ * 
+ * <p>JDBC 连接管理类</p>
+ * <p>使用该类需要具备两个条件：
+ * <li>1.数据库驱动jar包</li>
+ * <li>2.在src目录下生成db.properties，具有如下内容
+ * drivers=* 数据库连接驱动类
+ * idb.url=* 数据库连接URL
+ * idb.maxconn=* 线程最大连接数
+ * idb.user=* 数据库连接用户名
+ * idb.password=* 数据库连接密码
+ * </li>
+ * </p>
+ * @author 中科智源育成信息有限公司 E-mail: [email protected]
+ * @version 1.0 创建时间：2010-11-8 下午04:54:15
+ *
+ */
+public final class JdbcConnectionManager {
+	private static final JdbcConnectionManager jdbcConnectionManager = new JdbcConnectionManager() ; // 唯一实例
+	private static int clients;
+	private Vector drivers = new Vector();
+	private Hashtable pools = new Hashtable();
+	
+	//抑制默认的构造器,避免实例化对象
+	private JdbcConnectionManager(){
+		init();
+	}
+	
+	/**
+	 * 读取属性完成初始化
+	 */
+	private void init() {
+		
+		//InputStream is = getClass().getResourceAsStream("/db.properties");
+		
+		Properties dbProps = new Properties();
+		try {
+			InputStream is = JdbcConnectionManager.class.getClassLoader().getResourceAsStream("db.properties");
+			//InputStream is = new FileInputStream(System.getProperty("user.dir")+File.separator+"config"+File.separator+"db.properties");
+			dbProps.load(is);
+		    System.out.println("读取数据成功！");
+		} catch (Exception e) {
+			System.err.println("不能读取属性文件. "
+				+ "请确保db.properties在CLASSPATH指定的路径中");
+			throw new RuntimeException(new FileNotFoundException("unknow db.properties"));
+		}
+		loadDrivers(dbProps);
+		createPools(dbProps);
+	}
+
+	/**
+	 * 装载和注册所有JDBC驱动程序
+	 * 
+	 * @param props
+	 *            属性
+	 */
+	private void loadDrivers(Properties props) {
+		String driverClasses = props.getProperty("drivers");
+		StringTokenizer st = new StringTokenizer(driverClasses);
+		while (st.hasMoreElements()) {
+			String driverClassName = st.nextToken().trim();
+			
+			try {
+				
+				Driver driver = (Driver) Class.forName(driverClassName)
+						.newInstance();
+				DriverManager.registerDriver(driver);
+				drivers.addElement(driver);
+			} catch (Exception e) {
+				System.out.println("无法装载驱动，异常信息:" + e.getMessage());
+			}
+		}
+	}
+	
+	/**
+	 * 根据指定属性创建连接池实例.
+	 * 
+	 * @param props
+	 *            连接池属性
+	 */
+	private void createPools(Properties props) {
+		Enumeration propNames = props.propertyNames();
+		while (propNames.hasMoreElements()) {
+			String name = (String) propNames.nextElement();
+			if (name.endsWith(".url")) {
+				String poolName = name.substring(0, name.lastIndexOf("."));
+				String url = props.getProperty(poolName + ".url");
+				if (url == null) {
+					System.out.println("没有为连接池" + poolName + "指定URL");
+					continue;
+				}
+				String user = props.getProperty(poolName + ".user");
+				String password = props.getProperty(poolName + ".password");
+				String maxconn = props.getProperty(poolName + ".maxconn", "0");
+
+				int max;
+				try {
+					max = Integer.valueOf(maxconn).intValue();
+				} catch (NumberFormatException e) {
+					System.out.println("错误的最大连接数限制: " + maxconn + " .连接池: "
+							+ poolName);
+					max = 0;
+				}
+				DBConnectionPool pool = new DBConnectionPool(poolName, url,
+						user, password, max);
+				pools.put(poolName, pool);
+
+			}
+		}
+	}
+
+
+	/**
+	 * 返回singleton实例.如果是第一次调用此方法,则创建实例
+	 * 
+	 * @return JdbcConnectionManager 唯一实例
+	 */
+	 public  static synchronized JdbcConnectionManager getInstance() {
+		clients++;
+		return jdbcConnectionManager;
+	}
+
+	
+
+	/**
+	 * 将连接对象返回给由名字指定的连接池
+	 * 
+	 * @param name
+	 *            在属性文件中定义的连接池名字
+	 * @param conn
+	 *            连接对象
+	 */
+	public void freeConnection(String name, Connection conn) {
+		DBConnectionPool pool = (DBConnectionPool) pools.get(name);
+		if (pool != null) {
+			pool.freeConnection(conn);
+		}
+	}
+
+	/**
+	 * 获得一个可用的(空闲的)连接.如果没有可用连接,且已有连接数小于最大连接数 限制,则创建并返回新连接
+	 * 
+	 * @param name
+	 *            在属性文件中定义的连接池名字
+	 * @return Connection 可用连接或null
+	 */
+	public Connection getConnection(String name) throws DaoException{
+		DBConnectionPool pool = (DBConnectionPool) pools.get(name);
+		if (pool != null) {
+			return pool.getConnection();
+		}
+		return null;
+	}
+
+	/**
+	 * 获得一个可用连接.若没有可用连接,且已有连接数小于最大连接数限制, 则创建并返回新连接.否则,在指定的时间内等待其它线程释放连接.
+	 * 
+	 * @param name
+	 *            连接池名字
+	 * @param time
+	 *            以毫秒计的等待时间
+	 * @return Connection 可用连接或null
+	 */
+	public Connection getConnection(String name, long time)throws DaoException {
+		DBConnectionPool pool = (DBConnectionPool) pools.get(name);
+		if (pool != null) {
+			return pool.getConnection(time);
+		}
+		return null;
+	}
+
+	//返回多少个连接
+	private int getClient() {
+		return clients;
+	}
+
+	/**
+	 * 关闭所有连接,撤销驱动程序的注册
+	 */
+	public synchronized void release() {
+		// 等待直到最后一个客户程序调用
+		if (--clients != 0) {
+			return;
+		}
+
+		Enumeration allPools = pools.elements();
+		while (allPools.hasMoreElements()) {
+			DBConnectionPool pool = (DBConnectionPool) allPools.nextElement();
+			pool.release();
+		}
+
+		Enumeration allDrivers = drivers.elements();
+		while (allDrivers.hasMoreElements()) {
+			Driver driver = (Driver) allDrivers.nextElement();
+			try {
+				DriverManager.deregisterDriver(driver);
+	//			System.out.println("撤销JDBC驱动程序 " + driver.getClass().getName()
+	//					+ "的注册");
+			} catch (SQLException e) {
+				System.out.println("无法撤销下列JDBC驱动程序的注册: "
+					+ driver.getClass().getName() + "。错误信息："
+						+ e.getMessage());
+			}
+		}
+	}
+
+	/**
+	 * 
+	 * 清空PreparedStatement、Statement、ResultSet对象，未定义的置空。
+	 * @param pstmt  PreparedStatement对象
+	 * @param stmt  Statement对象
+	 * @param rs  ResultSet对象
+	 */
+	public void clear(PreparedStatement pstmt,Statement stmt,ResultSet rs) {
+		try {
+			if (stmt != null) {
+				stmt.close();
+			}
+			if (rs != null) {
+				rs.close();
+			}
+			if (pstmt != null) {
+				pstmt.close();
+			}
+		} catch (SQLException e) {
+			e.printStackTrace();
+		}
+		
+	}
+	
+
+	/**
+	 * 此内部类定义了一个连接池.它能够根据要求创建新连接,直到预定的最大连接数为止.在返回连接给客户程序之前,它能够验证连接的有效性.
+	 */
+	class DBConnectionPool {
+		private int checkedOut;
+		private Vector freeConnections = new Vector();
+		private int maxConn;
+		private String name;
+		private String password;
+		private String URL;
+		private String user;
+
+		/**
+		 * 创建新的连接池
+		 * 
+		 * @param name
+		 *            连接池名字
+		 * @param URL
+		 *            数据库的JDBC URL
+		 * @param user
+		 *            数据库帐号,或 null
+		 * @param password
+		 *            密码,或 null
+		 * @param maxConn
+		 *            此连接池允许建立的最大连接数
+		 */
+		public DBConnectionPool(String name, String URL, String user,
+				String password, int maxConn) {
+			this.name = name;
+			this.URL = URL;
+			this.user = user;
+			this.password = password;
+			this.maxConn = maxConn;
+		}
+
+		/**
+		 * 将不再使用的连接返回给连接池
+		 * 
+		 * @param con
+		 *            客户程序释放的连接
+		 */
+		public synchronized void freeConnection(Connection con) {
+			// 将指定连接加入到向量末尾
+			freeConnections.addElement(con);
+			checkedOut--;
+			//release();
+			notifyAll();
+		}
+
+		/**
+		 * 从连接池获得一个可用连接.如没有空闲的连接且当前连接数小于最大连接 数限制,则创建新连接.如原来登记为可用的连接不再有效,则从向量删除之,
+		 * 然后递归调用自己以尝试新的可用连接.
+		 */
+		public synchronized Connection getConnection() throws DaoException{
+			Connection con = null;
+			if (freeConnections.size() > 0) {
+				// 获取向量中第一个可用连接
+				con = (Connection) freeConnections.firstElement();
+				freeConnections.removeElementAt(0);
+				try {
+					if (con.isClosed()) {
+						// 递归调用自己,尝试再次获取可用连接
+						con = getConnection();
+					}
+				} catch (SQLException e) {
+					// 递归调用自己,尝试再次获取可用连接
+					con = getConnection();
+				}
+			} else if (maxConn == 0 || checkedOut < maxConn) {
+				con = newConnection();
+			}
+			if (con != null) {
+				checkedOut++;
+			}
+			return con;
+		}
+
+		/**
+		 * 从连接池获取可用连接.可以指定客户程序能够等待的最长时间 参见前一个getConnection()方法.
+		 * 
+		 * @param timeout
+		 *            以毫秒计的等待时间限制
+		 */
+		public synchronized Connection getConnection(long timeout) throws DaoException {
+			long startTime = new Date().getTime();
+			Connection con;
+			while ((con = getConnection()) == null) {
+				try {
+					wait(timeout);
+				} catch (InterruptedException e) {
+				}
+				if ((new Date().getTime() - startTime) >= timeout) {
+					// wait()返回的原因是超时
+					return null;
+				}
+			}
+			return con;
+		}
+
+		/**
+		 * 关闭所有连接
+		 */
+		public synchronized void release() {
+			Enumeration allConnections = freeConnections.elements();
+			while (allConnections.hasMoreElements()) {
+				Connection con = (Connection) allConnections.nextElement();
+				try {
+					con.close();
+				} catch (SQLException e) {
+             		System.out.println("无法关闭连接池" + name + "中的连接，错误信息："
+							+ e.getMessage());
+				}
+			}
+			freeConnections.removeAllElements();
+		}
+
+		/**
+		 * 创建新的连接
+		 */
+		private Connection newConnection() throws DaoException {
+			Connection con = null;
+			try {				
+				if (user == null) {
+					con = DriverManager.getConnection(URL);
+				} else {
+					con = DriverManager.getConnection(URL, user, password);
+				}				
+				System.out.println("连接池" + name + "创建一个新的连接");
+			} catch (SQLException e) {				
+				throw new DaoException("无法创建下列URL的连接:" + URL + "\n错误信息："+ e.getMessage());				
+			}
+			//freeConnections.addElement(con);
+			return con;
+		}
+	}
+
+}