发表于 2009-1-5 19:48
| 
涓涓畬澶囩殑鏁版嵁搴撹繛鎺ユ睜绫(bczt)
鍙戝竷: 2008-12-02 17:55 | 浣滆: webmaster | 鏉ユ簮: 鏈珯鍘熷垱 | 鏌ョ湅: 7娆
import java.sql.*;
import java.util.*;
import java.util.Date;
/**
* 绠＄悊绫籇BConnectionManager鏀寔瀵逛竴涓垨澶氫釜鐢卞睘鎬ф枃浠跺畾涔夌殑鏁版嵁搴撹繛鎺
* 姹犵殑璁块棶.瀹㈡埛绋嬪簭鍙互璋冪敤getInstance()鏂规硶璁块棶鏈被鐨勫敮涓瀹炰緥.
*/
public class DBConnectionManager {
static private DBConnectionManager instance; // 鍞竴瀹炰緥
static private int clients;
private Vector drivers = new Vector();
private PrintWriter log;
private Hashtable pools = new Hashtable();
/**
* 杩斿洖鍞竴瀹炰緥.濡傛灉鏄涓娆¤皟鐢ㄦ鏂规硶,鍒欏垱寤哄疄渚
*
* @return DBConnectionManager 鍞竴瀹炰緥
**/
static synchronized public DBConnectionManager getInstance() {
if (instance == null) {
instance = new DBConnectionManager();
}
clients++;
return instance;
}
/**
* 寤烘瀯鍑芥暟绉佹湁浠ラ槻姝㈠叾瀹冨璞″垱寤烘湰绫诲疄渚
*/
private DBConnectionManager() {
init();
}
/**
* 灏嗚繛鎺ュ璞¤繑鍥炵粰鐢卞悕瀛楁寚瀹氱殑杩炴帴姹
*
* @param name 鍦ㄥ睘鎬ф枃浠朵腑瀹氫箟鐨勮繛鎺ユ睜鍚嶅瓧
* @param con 杩炴帴瀵硅薄
**/
public void freeConnection(String name, Connection con) {
DBConnectionPool pool = (DBConnectionPool) pools.get(name);
if (pool != null) {
pool.freeConnection(con);
}
}
/**
* 鑾峰緱涓涓彲鐢ㄧ殑(绌洪棽鐨)杩炴帴.濡傛灉娌℃湁鍙敤杩炴帴,涓斿凡鏈夎繛鎺ユ暟灏忎簬鏈澶ц繛鎺ユ暟
* 闄愬埗,鍒欏垱寤哄苟杩斿洖鏂拌繛鎺
*
* @param name 鍦ㄥ睘鎬ф枃浠朵腑瀹氫箟鐨勮繛鎺ユ睜鍚嶅瓧
* @return Connection 鍙敤杩炴帴鎴杗ull
*/
public Connection getConnection(String name) {
DBConnectionPool pool = (DBConnectionPool) pools.get(name);
if (pool != null) {
return pool.getConnection();
}
return null;
}
/**
* 鑾峰緱涓涓彲鐢ㄨ繛鎺.鑻ユ病鏈夊彲鐢ㄨ繛鎺,涓斿凡鏈夎繛鎺ユ暟灏忎簬鏈澶ц繛鎺ユ暟闄愬埗,
* 鍒欏垱寤哄苟杩斿洖鏂拌繛鎺.鍚﹀垯,鍦ㄦ寚瀹氱殑鏃堕棿鍐呯瓑寰呭叾瀹冪嚎绋嬮噴鏀捐繛鎺.
*
* @param name 杩炴帴姹犲悕瀛
* @param time 浠ユ绉掕鐨勭瓑寰呮椂闂
* @return Connection 鍙敤杩炴帴鎴杗ull
*/
public Connection getConnection(String name, long time) {
DBConnectionPool pool = (DBConnectionPool) pools.get(name);
if (pool != null) {
return pool.getConnection(time);
}
return null;
}
/**
* 鍏抽棴鎵鏈夎繛鎺,鎾ら攢椹卞姩绋嬪簭鐨勬敞鍐
*/
public synchronized void release() {
// 绛夊緟鐩村埌鏈鍚庝竴涓鎴风▼搴忚皟鐢
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("鎾ら攢JDBC椹卞姩绋嬪簭 " + driver.getClass().getName() + "鐨勬敞鍐");
}
catch (SQLException e) {
log(e, "鏃犳硶鎾ら攢涓嬪垪JDBC椹卞姩绋嬪簭鐨勬敞鍐: " + driver.getClass().getName());
}
}
}
/**
* 鏍规嵁鎸囧畾灞炴у垱寤鸿繛鎺ユ睜瀹炰緥.
*
* @param props 杩炴帴姹犲睘鎬
*/
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) {
log("娌℃湁涓鸿繛鎺ユ睜" + poolName + "鎸囧畾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("閿欒鐨勬渶澶ц繛鎺ユ暟闄愬埗: " + maxconn + " .杩炴帴姹: " + poolName);
max = 0;
}
DBConnectionPool pool =
new DBConnectionPool(poolName, url, user, password, max);
pools.put(poolName, pool);
log("鎴愬姛鍒涘缓杩炴帴姹" + poolName);
}
}
}
/**
* 璇诲彇灞炴у畬鎴愬垵濮嬪寲
*/
private void init() {
InputStream is = getClass().getResourceAsStream("/db.properties");
Properties dbProps = new Properties();
try {
dbProps.load(is);
}
catch (Exception e) {
System.err.println("涓嶈兘璇诲彇灞炴ф枃浠. " +
"璇风‘淇漝b.properties鍦–LASSPATH鎸囧畾鐨勮矾寰勪腑");
return;
}
String logFile = dbProps.getProperty("logfile", "DBConnectionManager.log");
try {
log = new PrintWriter(new FileWriter(logFile, true), true);
}
catch (IOException e) {
System.err.println("鏃犳硶鎵撳紑鏃ュ織鏂囦欢: " + logFile);
log = new PrintWriter(System.err);
}
loadDrivers(dbProps);
createPools(dbProps);
}
/**
* 瑁呰浇鍜屾敞鍐屾墍鏈塉DBC椹卞姩绋嬪簭
*
* @param props 灞炴
*/
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);
log("鎴愬姛娉ㄥ唽JDBC椹卞姩绋嬪簭" + driverClassName);
}
catch (Exception e) {
log("鏃犳硶娉ㄥ唽JDBC椹卞姩绋嬪簭: " +
driverClassName + ", 閿欒: " + e);
}
}
}
/**
* 灏嗘枃鏈俊鎭啓鍏ユ棩蹇楁枃浠
*/
private void log(String msg) {
log.println(new Date() + ": " + msg);
}
/**
* 灏嗘枃鏈俊鎭笌寮傚父鍐欏叆鏃ュ織鏂囦欢
*/
private void log(Throwable e, String msg) {
log.println(new Date() + ": " + msg);
e.printStackTrace(log);
}
/**
* 姝ゅ唴閮ㄧ被瀹氫箟浜嗕竴涓繛鎺ユ睜.瀹冭兘澶熸牴鎹姹傚垱寤烘柊杩炴帴,鐩村埌棰勫畾鐨勬渶
* 澶ц繛鎺ユ暟涓烘.鍦ㄨ繑鍥炶繛鎺ョ粰瀹㈡埛绋嬪簭涔嬪墠,瀹冭兘澶熼獙璇佽繛鎺ョ殑鏈夋晥鎬.
*/
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;
/**
* 鍒涘缓鏂扮殑杩炴帴姹
*
* @param name 杩炴帴姹犲悕瀛
* @param URL 鏁版嵁搴撶殑JDBC URL
* @param user 鏁版嵁搴撳笎鍙,鎴 null
* @param password 瀵嗙爜,鎴 null
* @param maxConn 姝よ繛鎺ユ睜鍏佽寤虹珛鐨勬渶澶ц繛鎺ユ暟
*/
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;
}
/**
* 灏嗕笉鍐嶄娇鐢ㄧ殑杩炴帴杩斿洖缁欒繛鎺ユ睜
*
* @param con 瀹㈡埛绋嬪簭閲婃斁鐨勮繛鎺
*/
public synchronized void freeConnection(Connection con) {
// 灏嗘寚瀹氳繛鎺ュ姞鍏ュ埌鍚戦噺鏈熬
freeConnections.addElement(con);
checkedOut--;
notifyAll();
}
/**
* 浠庤繛鎺ユ睜鑾峰緱涓涓彲鐢ㄨ繛鎺.濡傛病鏈夌┖闂茬殑杩炴帴涓斿綋鍓嶈繛鎺ユ暟灏忎簬鏈澶ц繛鎺
* 鏁伴檺鍒,鍒欏垱寤烘柊杩炴帴.濡傚師鏉ョ櫥璁颁负鍙敤鐨勮繛鎺ヤ笉鍐嶆湁鏁,鍒欎粠鍚戦噺鍒犻櫎涔,
* 鐒跺悗閫掑綊璋冪敤鑷繁浠ュ皾璇曟柊鐨勫彲鐢ㄨ繛鎺.
*/
public synchronized Connection getConnection() {
Connection con = null;
if (freeConnections.size() > 0) {
// 鑾峰彇鍚戦噺涓涓涓彲鐢ㄨ繛鎺
con = (Connection) freeConnections.firstElement();
freeConnections.removeElementAt(0);
try {
if (con.isClosed()) {
log("浠庤繛鎺ユ睜" + name + "鍒犻櫎涓涓棤鏁堣繛鎺");
// 閫掑綊璋冪敤鑷繁,灏濊瘯鍐嶆鑾峰彇鍙敤杩炴帴
con = getConnection();
}
}
catch (SQLException e) {
log("浠庤繛鎺ユ睜" + name + "鍒犻櫎涓涓棤鏁堣繛鎺");
// 閫掑綊璋冪敤鑷繁,灏濊瘯鍐嶆鑾峰彇鍙敤杩炴帴
con = getConnection();
}
}
else if (maxConn == 0 || checkedOut < maxConn) {
con = newConnection();
}
if (con != null) {
checkedOut++;
}
return con;
}
/**
* 浠庤繛鎺ユ睜鑾峰彇鍙敤杩炴帴.鍙互鎸囧畾瀹㈡埛绋嬪簭鑳藉绛夊緟鐨勬渶闀挎椂闂
* 鍙傝鍓嶄竴涓猤etConnection()鏂规硶.
*
* @param timeout 浠ユ绉掕鐨勭瓑寰呮椂闂撮檺鍒
*/
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()杩斿洖鐨勫師鍥犳槸瓒呮椂
return null;
}
}
return con;
}
/**
* 鍏抽棴鎵鏈夎繛鎺
*/
public synchronized void release() {
Enumeration allConnections = freeConnections.elements();
while (allConnections.hasMoreElements()) {
Connection con = (Connection) allConnections.nextElement();
try {
con.close();
log("鍏抽棴杩炴帴姹" + name + "涓殑涓涓繛鎺");
}
catch (SQLException e) {
log(e, "鏃犳硶鍏抽棴杩炴帴姹" + name + "涓殑杩炴帴");
}
}
freeConnections.removeAllElements();
}
/**
* 鍒涘缓鏂扮殑杩炴帴
/**/
private Connection newConnection() {
Connection con = null;
try {
if (user == null) {
con = DriverManager.getConnection(URL);
}
}
catch (Exception e) {
log("鏃犳硶鍙栧緱鏂拌繛鎺");
}
return con;
}
}
}
涓嬮潰鏄疛avaDoc鏂囨。锛
Class DBConnectionManager
public class DBConnectionManager
绠＄悊绫籇BConnectionManager鏀寔瀵逛竴涓垨澶氫釜鐢卞睘鎬ф枃浠跺畾涔夌殑鏁版嵁搴撹繛鎺 姹犵殑璁块棶.瀹㈡埛绋嬪簭鍙互璋冪敤getInstance()鏂规硶璁块棶鏈被鐨勫敮涓瀹炰緥.
Constructor Detail
DBConnectionManagerprivate DBConnectionManager()
寤烘瀯鍑芥暟绉佹湁浠ラ槻姝㈠叾瀹冨璞″垱寤烘湰绫诲疄渚
--------------------------------------------------------------------------------
Method Detail
getInstancepublic static synchronized DBConnectionManager getInstance()
杩斿洖鍞竴瀹炰緥.濡傛灉鏄涓娆¤皟鐢ㄦ鏂规硶,鍒欏垱寤哄疄渚
Returns:
DBConnectionManager 鍞竴瀹炰緥
--------------------------------------------------------------------------------
freeConnectionpublic void freeConnection(java.lang.String name,
java.sql.Connection con)
灏嗚繛鎺ュ璞¤繑鍥炵粰鐢卞悕瀛楁寚瀹氱殑杩炴帴姹
Parameters:
name - 鍦ㄥ睘鎬ф枃浠朵腑瀹氫箟鐨勮繛鎺ユ睜鍚嶅瓧
con - 杩炴帴瀵硅薄
--------------------------------------------------------------------------------
getConnectionpublic java.sql.Connection getConnection(java.lang.String name)
鑾峰緱涓涓彲鐢ㄧ殑(绌洪棽鐨)杩炴帴.濡傛灉娌℃湁鍙敤杩炴帴,涓斿凡鏈夎繛鎺ユ暟灏忎簬鏈澶ц繛鎺ユ暟 闄愬埗,鍒欏垱寤哄苟杩斿洖鏂拌繛鎺
Parameters:
name - 鍦ㄥ睘鎬ф枃浠朵腑瀹氫箟鐨勮繛鎺ユ睜鍚嶅瓧
Returns:
Connection 鍙敤杩炴帴鎴杗ull
--------------------------------------------------------------------------------
getConnectionpublic java.sql.Connection getConnection(java.lang.String name,
long time)
鑾峰緱涓涓彲鐢ㄨ繛鎺.鑻ユ病鏈夊彲鐢ㄨ繛鎺,涓斿凡鏈夎繛鎺ユ暟灏忎簬鏈澶ц繛鎺ユ暟闄愬埗, 鍒欏垱寤哄苟杩斿洖鏂拌繛鎺.鍚﹀垯,鍦ㄦ寚瀹氱殑鏃堕棿鍐呯瓑寰呭叾瀹冪嚎绋嬮噴鏀捐繛鎺.
Parameters:
name - 杩炴帴姹犲悕瀛
time - 浠ユ绉掕鐨勭瓑寰呮椂闂
Returns:
Connection 鍙敤杩炴帴鎴杗ull
--------------------------------------------------------------------------------
releasepublic synchronized void release()
鍏抽棴鎵鏈夎繛鎺,鎾ら攢椹卞姩绋嬪簭鐨勬敞鍐
--------------------------------------------------------------------------------
createPoolsprivate void createPools(java.util.Properties props)
鏍规嵁鎸囧畾灞炴у垱寤鸿繛鎺ユ睜瀹炰緥.
Parameters:
props - 杩炴帴姹犲睘鎬
--------------------------------------------------------------------------------
initprivate void init()
璇诲彇灞炴у畬鎴愬垵濮嬪寲
--------------------------------------------------------------------------------
loadDriversprivate void loadDrivers(java.util.Properties props)
瑁呰浇鍜屾敞鍐屾墍鏈塉DBC椹卞姩绋嬪簭
Parameters:
props - 灞炴
--------------------------------------------------------------------------------
logprivate void log(java.lang.String msg)
灏嗘枃鏈俊鎭啓鍏ユ棩蹇楁枃浠
--------------------------------------------------------------------------------
logprivate void log(java.lang.Throwable e,
java.lang.String msg)
灏嗘枃鏈俊鎭笌寮傚父鍐欏叆鏃ュ織鏂囦欢
寮曡捣娉ㄦ剰鐨勶細
1.涓嶇敤log4j鍐欐棩蹇楁枃浠剁殑鏂规硶锛
String logFile = dbProps.getProperty("logfile", "DBConnectionManager.log");
try {
log = new PrintWriter(new FileWriter(logFile, true), true);
}
catch (IOException e) {
System.err.println("鏃犳硶鎵撳紑鏃ュ織鏂囦欢: " + logFile);
log = new PrintWriter(System.err);
}
2.鏁版嵁搴撹繛鎺ユ睜绫讳腑澶ч儴鍒嗘柟娉曢兘瀹氫箟涓簊ynchronized
3.鍦ㄦ暟鎹簱杩炴帴姹犱腑鏈夋暟閲忔帶鍒惰繛鎺ユ暟
4.Properties绫绘槸Hashtable鐨勫瓙绫伙紝鍏稿瀷鐢ㄩ斿姝ゆ枃浠舵墍璇村彲浠oad涓涓枃浠讹紝杩欎釜鏂囦欢鏄敭鍊煎褰㈠紡銆
InputStream is = getClass().getResourceAsStream("/db.properties");
Properties dbProps = new Properties();
try {
dbProps.load(is);
}
catch (Exception e) {
System.err.println("涓嶈兘璇诲彇灞炴ф枃浠. " +
"璇风‘淇漝b.properties鍦–LASSPATH鎸囧畾鐨勮矾寰勪腑");
return;
}
