dbconnection.java

一个数据库连接池的完整代码

package eise.db;
//------------------------------------------------------------------------------
import java.io.*;
import java.sql.*;
import java.util.*;
//------------------------------------------------------------------------------
public class DBConnection{
  Connection conn=null;
  Statement stmt=null;
  ResultSet rset=null;
  DBConnectionManager connMgr=null;
//------------------------------------------------------------------------------
    public DBConnection(){
    }
//------------------------------------------------------------------------------
    public void close() throws SQLException{
        if(conn!=null){conn.close();}
        if(rset!=null){rset.close();}
        if(stmt!=null){stmt.close();}
    }
//------------------------------------------------------------------------------
    public ResultSet executeQuery(String sql_str) throws SQLException{
        stmt = conn.createStatement();
        rset = stmt.executeQuery(sql_str);
        return rset;
    }
//------------------------------------------------------------------------------
    public void executeUpdate(String sql_str) throws SQLException{
        stmt = conn.createStatement();
        stmt.executeUpdate(sql_str);
        if(stmt != null){stmt.close();}
    }
//------------------------------------------------------------------------------
    protected void finalize() throws Throwable{
        close();
    }
//------------------------------------------------------------------------------
    public void freeConnection(String db_type_name){
        connMgr.freeConnection(db_type_name, conn);
    }
//------------------------------------------------------------------------------
    public Connection getConn(){
        return conn;
    }
//------------------------------------------------------------------------------
    public static void main(String args[]){
        DBConnection dbconnection = new DBConnection();
        System.out.println(dbconnection.openConnection());
    }
//------------------------------------------------------------------------------
    public boolean openConnection(){
        Properties properties = new Properties();
        try{InputStream inputstream = getClass().getResourceAsStream("db_connection.properties");
            properties.load(inputstream);
            if(inputstream != null){inputstream.close();}
           }
        catch(IOException _ex){System.out.println("Can not open db_connect.properties");}
        String driver_name = properties.getProperty("db_driver");
        String url_string = properties.getProperty("db_url");
        try{Class.forName(driver_name).newInstance();}
        catch(ClassNotFoundException classnotfoundexception)
           {System.out.println("JDBC驱动注册失败：" + classnotfoundexception.getMessage());
            return false;
           }
        catch(Exception exception)
           {System.err.println("无法加载数据库驱动");
            exception.printStackTrace();
           }
        try{conn = DriverManager.getConnection(url_string);}
        catch(SQLException sqlexception)
           {System.out.println("Generate Connection, Error!" + sqlexception.getMessage());
            return false;
           }
        return true;
    }
//------------------------------------------------------------------------------
    public boolean openConnection(String db_type_name){
        connMgr = DBConnectionManager.getInstance();
        conn = connMgr.getConnection(db_type_name);
        return conn != null;
    }
//------------------------------------------------------------------------------
    public boolean openConnection(String db_type_name, long limit_long){
        connMgr = DBConnectionManager.getInstance();
        conn = connMgr.getConnection(db_type_name, limit_long);
        return conn != null;
    }
//------------------------------------------------------------------------------
    public void release(){
        connMgr.release();
    }
//------------------------------------------------------------------------------
}//end of class
//------------------------------------------------------------------------------