功能完善的Java连接池调用实例

功能完善的Java连接池调用实例/*** Title: ConnectPool.java* Description: 连接池管理器* Copyright: Copyright (c) 2002/12/25* Company:* Author :* V ersion 2.0*/import java.io.*;import java.sql.*;import java.util.*;import java.util.Date;/*** 管理类DBConnectionManager支持对一个或多个由属性文件定义的数据库连接* 池的访问.客户程序可以调用getInstance()方法访问本类的唯一实例. */public class ConnectPoolstatic public ConnectPool instance; // 唯一实例static public int clients;public V ector drivers = new V ector(); //驱动public PrintWriter log;public Hashtable pools = new Hashtable(); //连接/*** 返回唯一实例.如果是第一次调用此方法,则创建实例** @return DBConnectionManager 唯一实例*/static synchronized public ConnectPool getInstance() {if (instance == null){instance = new ConnectPool();}clients++;return instance;/*** 建构函数私有以防止其它对象创建本类实例*/public ConnectPool() {init();}/*** 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 con 连接对象*/public void freeConnection(String name, Connection con){DBConnectionPool pool = (DBConnectionPool) pools.get(name); if (pool != null){pool.freeConnection(con);}else{System.out.println("pool ==null");}clients--;}/*** 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){DBConnectionPool pool = (DBConnectionPool) pools.get(name);if (pool != null){//return pool.getConnection();return pool.returnConnection();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){DBConnectionPool pool = (DBConnectionPool) pools.get(name);if (pool != null){return pool.getConnection(time);}return null;}/*** 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);log("撤销JDBC驱动程序" + driver.getClass().getName()+"的注册"); }catch (SQLException e){log(e, "无法撤销下列JDBC驱动程序的注册: " + driver.getClass().getName());}}}/*** 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, stIndexOf("."));String url = props.getProperty(poolName + ".url");if (url == null) {log("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){log("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);log("成功创建连接池" + poolName);}}}/*** 读取属性完成初始化*/private void init(){try{Properties p = new Properties();String configs = System.getProperty("user.dir")+"confdb.properties";System.out.println("configs file local at "+configs); FileInputStream is = new FileInputStream(configs);Properties dbProps = new Properties();try{dbProps.load(is);}catch (Exception e){System.err.println("不能读取属性文件. " +"请确保db.properties在CLASSPA TH指定的路径中");return;}String logFile = dbProps.getProperty("logfile", "DBConnectionManager.log");try{log = new PrintWriter(new FileWriter(logFile, true), true);}catch (IOException e){System.err.println("无法打开日志文件: " + logFile);log = new PrintWriter(System.err);}loadDrivers(dbProps);createPools(dbProps); }catch(Exception e){}}/**171 * 装载和注册所有JDBC驱动程序172 *173 * @param props 属性174 */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);System.out.println(driverClassName);log("成功注册JDBC驱动程序" + driverClassName); }catch (Exception e)log("无法注册JDBC驱动程序: " + driverClassName + ", 错误: " + e);}}}/*** 将文本信息写入日志文件*/private void log(String msg){log.println(new Date() + ": " + msg);}/*** 将文本信息与异常写入日志文件*/private void log(Throwable e, String msg) {log.println(new Date() + ": " + msg);e.printStackTrace(log);/*** 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 V ector freeConnections = new V ector();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){ = name;this.URL = URL;er = 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try{if(con.isClosed()){System.out.println("before freeConnection con is closed");}freeConnections.addElement(con);Connection contest = (Connection) stElement();if(contest.isClosed()){System.out.println("after freeConnection contest is closed");}notifyAll();}catch(SQLException e){System.out.println(e);}}/*** 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(){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()){log("从连接池" + name+"删除一个无效连接");System.out.println("从连接池" + name+"删除一个无效连接");// 递归调用自己,尝试再次获取可用连接con = getConnection();}}catch (SQLException e){log("从连接池" + name+"删除一个无效连接时错误"); System.out.println("从连接池" + name+"删除一个无效连接出错"); // 递归调用自己,尝试再次获取可用连接con = getConnection();}if(freeConnections.size()>maxConn){ System.out.println(" 删除一个溢出连接"); releaseOne();}}else if((maxConn == 0)||(freeConnections.size()<maxConn)) {con = newConnection();}return con;}public synchronized Connection returnConnection(){Connection con = null;//如果闲置小于最大连接,返回一个新连接if(freeConnections.size()<maxConn){con = newConnection();}//如果闲置大于最大连接，返回一个可用的旧连接else if(freeConnections.size()>=maxConn){con = (Connection) freeConnections.firstElement();System.out.println(" [a 连接池可用连接数] : "+"[ "+freeConnections.size()+" ]");freeConnections.removeElementAt(0);System.out.println(" [b 连接池可用连接数] : "+"[ "+freeConnections.size()+" ]");try{if (con.isClosed()){log("从连接池" + name+"删除一个无效连接");System.out.println("从连接池" + name+"删除一个无效连接"); returnConnection();}}catch (SQLException e){log("从连接池" + name+"删除一个无效连接时错误");System.out.println("从连接池" + name+"删除一个无效连接出错");returnConnection();}}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){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();log("关闭连接池" + name+"中的一个连接");}catch (SQLException e){log(e, "无法关闭连接池" + name+"中的连接");}}freeConnections.removeAllElements();}/*** 关闭一个连接*/public synchronized void releaseOne(){if(freeConnections.firstElement()!=null){ Connection con = (Connection) freeConnections.firstElement(); try {con.close();System.out.println("关闭连接池" + name+"中的一个连接"); log("关闭连接池" + name+"中的一个连接");}catch (SQLException e){System.out.println("无法关闭连接池" + name+"中的一个连接");log(e, "无法关闭连接池" + name+"中的连接");}}else{System.out.println("releaseOne() bug.......................................................");}}/*** 创建新的连接*/private Connection newConnection(){Connection con = null;try{if (user == null) {con = DriverManager.getConnection(URL);}else{con = DriverManager.getConnection(URL, user, password); }log("连接池" + name+"创建一个新的连接");}catch (SQLException e) {log(e, "无法创建下列URL的连接: " + URL);return null;}return con;}}}================================/*** Title: ConnectPool.java* Description: 数据库操作* Copyright: Copyright (c) 2002/12/25* Company:* Author :* remark : 加入指针回滚* V ersion 2.0*/import java.io.*;import com.sjky.pool.*;import java.sql.*;import java.util.*;import java.util.Date;import .*;public class PoolMan extends ConnectPool {private ConnectPool connMgr;private Statement stmt;private Connection con ;private ResultSet rst;/***对象连接初始化* */public Connection getPool(String name) throws Exception{try{connMgr = ConnectPool.getInstance();con = connMgr.getConnection(name);}catch(Exception e){System.err.println("不能创建连接!请尝试重启应用服务器");}return con;}/***同以上方法,加入连接空闲等待时间*待用方法* */public Connection getPool_t(String name, long time) throws Exception {try{connMgr = ConnectPool.getInstance();con = connMgr.getConnection(name,time);}catch(Exception e){System.err.println("不能创建连接!");}return con;}/***执行查询方法1* */public ResultSet executeQuery(String SqlStr) throws Exception {ResultSet result = null;try{stmt = con.createStatement();result = stmt.executeQuery(SqlStr);// here add one line by jnma 12.11mit();}catch(java.sql.SQLException e){throw new Exception("执行查询语句出错");}return result;}/***执行查询方法2* */public ResultSet getRst(String SqlStr) throws Exception{// ResultSet result = null;try{stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet. CONCUR_UPDA TABLE);rst = stmt.executeQuery(SqlStr);// here add one line by jnma 12.11mit();}catch(java.sql.SQLException e){throw new Exception("执行查询语句出错");}return rst;}/***执行更新* */public int Update(String SqlStr) throws Exception{int result = -1;try{stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet. CONCUR_UPDA TABLE);result = stmt.executeUpdate(SqlStr);// here add one line by jnma 12.11mit();if(result==0)System.out.println("执行delete,update,insert SQL出错");}catch(java.sql.SQLException e){System.err.println("执行delete,update,insert SQL出错");}return result;}/***执行事务处理* */public boolean handleTransaction(V ector SqlArray) throws Exception {boolean result = false;int ArraySize = SqlArray.size();try{stmt = con.createStatement();con.setAutoCommit(false);System.out.println("ArraySize is" +ArraySize);for(int i=0;i<ArraySize;i++){System.out.println(" 开始执行语句"+(String)SqlArray.elementAt(i)); stmt.executeUpdate((String)SqlArray.elementAt(i));System.out.println(" 执行成功");}mit();con.setAutoCommit(true) ;//必须System.out.println("事务执行成功"); result = true;}catch(java.sql.SQLException e){try{System.out.println(e.toString()); System.out.println("数据库操作失败"); con.rollback();}catch(java.sql.SQLException Te){System.err.println("事务出错回滚异常"); }}try{con.setAutoCommit(true);}catch(java.sql.SQLException e){System.err.println("设置自动提交失败");}return result;}/***释放连接* */public void close(String name) throws Exception {try{if(stmt!=null)stmt.close();if(con!=null){connMgr.freeConnection(name,con);System.out.println(" [c 正在释放一个连接] ");}}catch(java.sql.SQLException e){System.err.println("释放连接出错");}}}===========================属性文件db.properties放在conf下#drivers=com.inet.tds.TdsDriver#logfile=c: esin-2.1.4DBConnectPool-log.txt#test.maxconn=1000#test.url=jdbc:inetdae:SERVER:1433?sql7=true#er=sa#test.password=testdrivers=com.microsoft.jdbc.sqlserver.SQLServerDriverlogfile=F: esin-2.1.4DBConnectPool-log.txttest.maxconn=20test.url=jdbc:microsoft:sqlserver://192.168.0.5:1433;DatabaseName=test er=satest.password=test#drivers=oracle.jdbc.driver.OracleDriver#logfile=c: esin-2.1.4DBConnectPool-log.txt#test.maxconn=100#test.url=jdbc:oracle:thin:@192.168.0.10:1521:myhome#er=system#test.password=manager#mysql端3306#drivers=org.gjt.mm.mysql.Driver#logfile=c: esin-2.1.4DBConnectPool-log.txt#test.maxconn=100#test.url=jdbc:mysql://192.168.0.4:3306/my_test#er=root#test.password=system原作者：薄冰来源：。