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JDBC數據庫連接池

ConnectionHandler.java

package?com.ofis.DBConnection;

import?java.lang.reflect.*;

import?java.sql.*;

import?org.apache.xalan.lib.sql.ConnectionPool;

/**

?*?

?*?數據庫連接的代理類

?*/

class?ConnectionHandler?implements?InvocationHandler?{

????Connection?dbconn;

????ConnectionPool?pool;

????/**

?????*?構造函數

?????*?@param?connPool

?????*/

????public?ConnectionHandler(ConnectionPool?connPool)?{

????????this.pool?=?connPool;

????}

????/**

?????*?

?????*?動態綁定Connection

?????*?@param?conn?Connection

?????*?@return?Connection

?????*?

?????*/

????public?Connection?bind(Connection?conn)?{

????????Class[]?interfaces?=?conn.getClass().getInterfaces();

????????if?(interfaces?==?null?||?interfaces.length?==?0)?{

????????????interfaces?=?new?Class[1];

????????????interfaces[0]?=?Connection.class;

????????}

????????Connection?proxyConn?=?(Connection)?Proxy.newProxyInstance(conn.

????????????????getClass().getClassLoader(),?interfaces,?this);

????????return?conn;

????}

????/**

?????*?調用攔截函數

?????*/

????public?Object?invoke(Object?object,?Method?method,?Object[]?objectArray)?throws

????????????Throwable?{

????????Object?obj?=?null;

????????if?("close".equals(method.getName()))?{

????????????pool.releaseConnection(dbconn);

????????}?else?{

????????????obj?=?method.invoke(dbconn,?objectArray);

????????}

????????return?obj;

????}

}

DBConnectionPool.java

package?com.ofis.DBConnection;

import?org.apache.xalan.lib.sql.ConnectionPool;

import?java.sql.*;

import?java.sql.SQLException;

import?java.util.Properties;

import?java.util.Vector;

/**

?*?數據庫連接池控制

?*/

public?class?DBConnectionPool?implements?ConnectionPool{

????private?static?Vector?pool;

????private?final?int?POOL_MAX_SIZE=40;

????static?String?strDriver?=?"net.sourceforge.jtds.jdbc.Driver";

????static?String?strURL?="jdbc:jtds:sqlserver://localhost:1433/template";

????public?DBConnectionPool()?{

????}

????public?boolean?isEnabled()?{

????????return?false;

????}

????public?void?setDriver(String?string)?{

????????this.strDriver?=?string;

????}

????public?void?setURL(String?string)?{

????????this.strURL=string;

????}

????public?void?freeUnused()?{

????}

????public?boolean?hasActiveConnections()?{

????????return?false;

????}

????public?void?setPassword(String?string)?{

????}

????public?void?setUser(String?string)?{

????}

????public?void?setMinConnections(int?_int)?{

????}

????public?boolean?testConnection()?{

????????return?false;

????}

????/**

?????*?得到數據庫連接操作

?????*/

????public?synchronized?Connection?getConnection()?throws?SQLException?{

????????if(pool==null){

????????????pool=new?Vector();

????????}

????????Connection?conn;

????????if(pool.isEmpty()){

????????????conn=createConnection();

????????}else{

????????????int?last_idx=pool.size()-1;

????????????conn=(Connection)pool.get(last_idx);

????????????pool.remove(pool.get(last_idx));

????????}

????????ConnectionHandler?connHandler=new?ConnectionHandler(this);

????????return?connHandler.bind(conn);

????}

????/**

?????*?釋放數據庫連接操作

?????*/

????public?synchronized?void?releaseConnection(Connection?connection)?throws?SQLException?{

????????if(pool.size()>POOL_MAX_SIZE){

????????????try?{

????????????????connection.close();

????????????}?catch?(SQLException?ex)?{

????????????????ex.printStackTrace();

????????????}

????????}else{

????????????pool.add(connection);

????????}

????}

????/**

?????*?創建數據庫連接操作

?????*?@return

?????*/

????private?static?Connection?createConnection(){

????????Connection?conn;

????????try?{

????????????Class.forName(strDriver);

????????????conn?=?DriverManager.getConnection(strURL,?"sa",?"");

????????????return?conn;

????????}?catch?(SQLException?ex)?{

????????????return?null;

????????}?catch?(ClassNotFoundException?ex)?{

????????????return?null;

????????}

????}

????public?void?releaseConnectionOnError(Connection?connection)?throws

????????????SQLException?{

????}

????public?void?setPoolEnabled(boolean?_boolean)?{

????}

????public?void?setProtocol(Properties?properties)?{

????}

}

DBHelper.java

package?com.ofis.DBConnection;

import?java.sql.*;

/**

?*?數據庫連接操作

?*/

public?class?DBHelper?{

????/**

?????*?得到數據庫連接

?????*?@return

?????*/

????public?static?Connection?getConnection()?{

????????DBConnectionPool?cp=new?DBConnectionPool();

????????cp.setDriver("net.sourceforge.jtds.jdbc.Driver");

????????cp.setURL("jdbc:jtds:sqlserver://localhost:1433/template");

????????Connection?conn?=?null;

????????try?{

????????????conn?=?cp.getConnection();

????????}?catch?(SQLException?ex)?{

????????}

????????return?conn;

??}

????/**

?????*?釋放數據庫連接

?????*?@param?conn?

?????*/

????public?static?void?releaseConnection(Connection?conn){

????????DBConnectionPool?cp=new?DBConnectionPool();

????????try?{

????????????cp.releaseConnection(conn);

????????}?catch?(SQLException?ex)?{

????????}

????}

}

DBHelperTest.java

package?com.ofis.DBConnection;

import?java.sql.Connection;

import?java.sql.ResultSet;

import?java.sql.SQLException;

import?java.sql.Statement;

import?com.ofis.DBConnection.DBHelper;

import?junit.framework.TestCase;

public?class?DBHelperTest?extends?TestCase?{

????/*

?????*?Test?method?for?'com.ofis.DBConnection.DBHelper.getConnection()'

?????*/

????public?void?testGetConnection()?{

????????Connection?h1?=?DBHelper.getConnection()?;

????????Connection?h2?=?DBHelper.getConnection()?;

????????Connection?h3?=?DBHelper.getConnection()?;

????????Connection?h4?=?DBHelper.getConnection()?;

????????Connection?h5?=?DBHelper.getConnection()?;

????????try{

????????????Statement?stmt?=?h1.createStatement();

????????????ResultSet?rs?=?stmt.executeQuery("select?*?from?tbusers");

????????????if(rs.next())

????????????{

????????????????System.out.println(rs.getString("user_truename"));

????????????}

????????}

????????catch(SQLException?ex){

????????????System.err.println(ex.getMessage());

????????}????????

????????finally?{

????????????if?(h1?!=?null)?{

????????????????DBHelper.releaseConnection(h1);

????????????}

????????????if?(h2?!=?null)?{

????????????????DBHelper.releaseConnection(h2);

????????????}

????????????if?(h3?!=?null)?{

????????????????DBHelper.releaseConnection(h3);

????????????}

????????????if?(h4?!=?null)?{

????????????????DBHelper.releaseConnection(h4);

????????????}

????????????if?(h5?!=?null)?{

????????????????DBHelper.releaseConnection(h5);

????????????}

????????????testCon();

????????????

????????}

????}

????public?void?testCon(){

????????Connection?h1?=?DBHelper.getConnection()?;

????????Connection?h2?=?DBHelper.getConnection()?;

????????try{

????????????Statement?stmt?=?h1.createStatement();

????????????ResultSet?rs?=?stmt.executeQuery("select?*?from?tbusers");

????????????if(rs.next())

????????????{}

????????}

????????catch(SQLException?ex){

????????????System.err.println(ex.getMessage());

????????}????????

????????finally?{

????????????if?(h1?!=?null)?{

????????????????DBHelper.releaseConnection(h1);

????????????}

????????????if?(h2?!=?null)?{

????????????????DBHelper.releaseConnection(h2);

????????????}

//????????????if?(h3?!=?null)?{

//????????????????DBHelper.releaseConnection(h3);

//????????????}

//????????????if?(h4?!=?null)?{

//????????????????DBHelper.releaseConnection(h4);

//????????????}

//????????????if?(h5?!=?null)?{

//????????????????DBHelper.releaseConnection(h5);

//????????????}

????????????

????????}

????}

}

posted on 2006-09-30 13:42 young 閱讀(308) 評論(0) 編輯收藏所屬分類: java

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JDBC數據庫連接池