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在jsp里有两种实现的办法，一种是用jndi(java naming directory interface)，这可能和应用服务器有关，如果是resin，先在resin.conf里定义
<resource-ref>
<res-ref-name>jdbc/oracle</res-ref-name>
<res-type>javax.sql.datasource</res-type>
<init-param driver-name="oracle.jdbc.driver.oracledriver"/>
<init-param url="jdbc:oracle:thin:@192.168.1.1:1521:oracle"/>
<init-param user="system"/>
<init-param password="manager"/>
<init-param max-connections="20"/>
<init-param max-idle-time="30"/>
</resource-ref>
如果为tomcat，在server.xml里面定义，有关的资料可以查文档，然后在jsp里这样用
try{
javax.naming.context env = (context)new initialcontext().lookup("java:comp/env");
javax.sql.datasource pool=(javax.sql.datasource) env.lookup("jdbc/oracle");
}catch(exception e){system.err.println("exception error:"+e.getmessage());}
try {
connection conn = pool.getconnection();
}catch(exception e){system.out.println("exception error:"+e.getmessage());}
通过这段代码，你就获得从连接池里获得了一个连接conn。如果想用普通的连接池，那只能用javabean了，先写一个connectionpool的java的类，然后直接从连接池中获得连接，下面是我一个连接池的javabean
connectionpool.java如下：
import java.io.printstream;
import java.sql.connection;
import java.util.vector;
// referenced classes of package com.ilovejsp.sql:
// datasource, pooledconnection
public class connectionpool
{
private vector pool;
private int size;
datasource db;
public connectionpool()
{
pool = null;
size = 0;
db = new datasource();
}
public void setsize(int value)
{
if(value > 1)
size = value;
}
public int getsize()
{
return size;
}
public synchronized void initpool()
throws exception
{
try
{
for(int x = 0; x < size; x++)
{
connection conn = db.getconnection();
if(conn != null)
{
pooledconnection pcon = new pooledconnection(conn);
addconnection(pcon);
}
}
}
catch(exception e)
{
system.err.println(e.getmessage());
}
}
private void addconnection(pooledconnection pcon)
{
if(pool == null)
pool = new vector(size);
pool.addelement(pcon);
}
public synchronized void releaseconnection(connection conn)
{
int x = 0;
do
{
if(x >= pool.size())
break;
pooledconnection pcon = (pooledconnection)pool.elementat(x);
if(pcon.getconnection() == conn)
{
system.err.println("release connection".concat(string.valueof(string.valueof(x))));
pcon.setinuse(false);
break;
}
x++;
}
while(true);
}
public synchronized connection getconnection()
throws exception
{
pooledconnection pcon = null;
for(int x = 0; x < pool.size(); x++)
{
pcon = (pooledconnection)pool.elementat(x);
if(!pcon.inuse())
{
pcon.setinuse(true);
return pcon.getconnection();
}
}
try
{
connection conn = db.getconnection();
pcon = new pooledconnection(conn);
pcon.setinuse(true);
pool.addelement(pcon);
}
catch(exception e)
{
system.err.println("exception error:".concat(string.valueof(string.valueof(e.getmessage()))));
}
return pcon.getconnection();
}
public synchronized void emptypool()
{
for(int x = 0; x < pool.size(); x++)
{
system.err.println("closing jdbc connection".concat(string.valueof(string.valueof(x))));
pooledconnection pcon = (pooledconnection)pool.elementat(x);
if(!pcon.inuse())
{
pcon.close();
continue;
}
try
{
thread.sleep(3000l);
pcon.close();
}
catch(exception e)
{
system.out.println("exception :".concat(string.valueof(string.valueof(e.getmessage()))));
}
}
db.close();
}
}
testpool.jsp内容如下：
<%@ page language="java" contenttype="text/html;charset=gb2312"%>
<%@ page import="java.sql.*"%>
<html>
<head>
<title>系统数据信息</title>
</head>
<body>
<%connectionpool db=new connectionpool();
connection conn=db.getconnection();
statement stmt=conn.createstatement();
string sql1="select * from pg_database ";
resultset rs=stmt.executequery(sql1);
%>
<table><tr><td>系统数据库信息</td></tr>
<tr><td>
<%while(rs.next()) {
%>
<%=rs.getstring(1)%>
<%}
rs.close();%>
</tr></td>
<table><tr><td>系统字段信息</td></tr>
<tr><td>
<%string sql2="select * from pg_type";
rs=stmt.executequery(sql2);
while(rs.next()) {
%>
(<%=rs.getstring(1)%>)
<%}
rs.close();
db.close();%>
</tr></td>
</body>
</html>
