Java Documentation to Connection Pooling?
Hello,
is there any Java API documentation to the Connection Pooling available? It is not listed in the SP03-Docu, but the classes exist. I don't know how to use them, so any help would be appreciated.
Ah, and the Weblogs by Uri Katz are good, but not applicable in my case. I would like to mount a standalone HTTP server on my computer managing the connections to MDM.
Thanks in advance,
Jörg Thiesmann
I too would like to see more documentation and a simple working example of this ever so useful functionality ;}
Similar Messages
-
How database connection pooling works in a application
Hi Guys,
I am new to Java and looking into best way of doing J2ee database conectivity. I am using Eclipse galileo3.5 J2EE with Mysql database and Tomcate 6.0.
I am developing an email application where I need to implement MVC model for my webapplication, using jsp for presentation, servlet for control and java beans for model.
I came across two tutorial for database connection pooling as given below.
Eclipse Corner Article: Creating Database Web Applications with Eclipse - In this tutorial connection pooling is configure in Tomcate 6.0
It says Copy and paste the following into your context.xml file (you may have to click on the Source tab at the bottom of the editor to be able to paste). This defines a DataSource with the name "jdbc/SampleDB". Our application will retrieve database connections from the pool using this name.
<?xml version="1.0" encoding="UTF-8"?>
<Context>
<Resource name="jdbc/SampleDB" auth="Container"
type="javax.sql.DataSource"
username="app" password="app"
driverClassName="org.apache.derby.jdbc.ClientDrive r"
url="jdbc:derby://localhost:1527/sample"
maxActive="8" />
</Context>
Where as in second tutorial - http://www.roseindia.net/answers/viewanswers/2838.html
It uses java bean for connection pooling and then use straight way in JSP and no Servlet used.
conpool.jsp
<%@page import="java.sql.Connection"%>
<jsp:useBean id="pl" class="com.CoreJava.ConnectionPooling"/>
<% Connection con = pl.getConnection(); %>
//do something using con
connectionPooling.java
import com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolD ataSource;
public class ConnectionPooling
static Connection con=null;
public static Connection getConnection()
try
MysqlConnectionPoolDataSource po=new MysqlConnectionPoolDataSource();
po.setServerName("localhost");
po.setPortNumber(3306);
po.setDatabaseName("mydatabase"); //changeur database name
po.setUser("root");//ur username
po.setPassword("");//ur password
con = po.getConnection();
catch(Exception e)
System.out.println("Exception Connection :"+e);
return con;
Please some one explain which is the best way of doing connection pooling to the database by using MVC pattern
Please if some one advise me how to use MVC architecture for simple email application and database connectivty.
Thanks>
>
Where as in second tutorial - http://www.roseindia.net/answers/viewanswers/2838.html
Never EVER use roseindia. It is terrible shit.
[http://balusc.blogspot.com/2008/06/what-is-it-with-roseindia.html]
The correct answer is what you found in the eclipse article. And you can read the Tomcat docs for more.
As per usual the code you have posted from Roseindia is a big pile of rubbish that was written by a complete idiot. I mean the person who wrote it apparently doesn't know much Java at all. Let alone JDBC. Or Connection pools. Or J2EE. It's not the worst I've seen from them but it's pretty bad. -
Oracle: slow performance with SELECT using ojdbc14 and connection pooling
Hello,
i'm working hard the last days to solve a performance problem with our customer using a oracle 10g database. For testing I used our oracle 9.2.0.1.0 database which shows the same symptoms. All doing solved nothing: the performance while using this oracle is much slower than other databases. This result I cannot trust and so I need some advice. What is missing to improve the performance on the java side?
The webapplication I use runs fast on MySQL 4.x and SQLServer 2000, but on the above mentioned Oracle it was always 4 times slower. The webapplication uses a lot of simple SELECT-Statements without complicated joins and so on (because it should run on many different databases). Doing some days of creating tests within this webapplication, I was not able to find any entrance point for a change. All databases server I'm using, having only the default configurations after a common installation.
To reduce the complexity I wrote a simple java application with connection pooling using only the latest libraries from apache-commons(dbcp, pool), and the latest ojdbc14 for oracle 9.2.
First the results than the code: MySQL needed less than 1000 millisecond, SQLServer around 1000 milliseconds and Oracle over 2000 milliseconds. I stopped pooling and the results are for Oracle even worse: over 18000 milliseconds (mysql:2500, sqlserver:4100).
I changed the classes for Oracle and used the class oracle.jdbc.pool.OracleConnectionCacheImpl from the ojdbc14-library. No difference (around 100 milliseconds more or less).
The only Select-Statement works on this table, which has one index on HICTGID.
It contains 259 entrances.:
CREATE TABLE HIERARCHYCATEGORY (
HICTGID NUMBER (19) NOT NULL,
HICTGLEVEL NUMBER (10) NOT NULL,
HICTGEXTID NUMBER (19) NOT NULL,
HICTGEXTPARENTID NUMBER (19) NOT NULL,
HICTGNAME VARCHAR2(255) NOT NULL
);The application simply loops through this table using
SELECT Hictgid, Hictgname FROM HIERARCHYCATEGORY WHERE HICTGID = ?, but I always open a connection before this query and closes this connection afterwards. So I use the pooling as much as possible. That's all SQL I'm using.
protected static DataSource setupDataSource(String sDriver, String sUrl, String sUser, String sPwd) throws SQLException {
BasicDataSource ds = new BasicDataSource();
ds.setDriverClassName(sDriver);
ds.setUsername(sUser);
ds.setPassword(sPwd);
ds.setUrl(sUrl);
// The maximum number of active connections:
ds.setMaxActive(3);
// The maximum number of active connections that can remain idle in the pool,
// without extra ones being released, or zero for no limit:
ds.setMaxIdle(3);
// The maximum number of milliseconds that the pool will wait (when there are no available connections)
// for a connection to be returned before throwing an exception, or -1 to wait indefinitely:
ds.setMaxWait(3000);
return ds;
}I can switch by using external properties between three databases (oracle, mysql and sqlserver) and if I want I can switch pooling off. And all actions I'm interested are logged by Log4J.
public static Connection getConnection() throws SQLException {
Connection result = null;
String sJdbcDriver = m_oJbProp.getString("jdbcDriver");
String sJdbcUrl = m_oJbProp.getString("databaseConnection");
String sJdbcUser = m_oJbProp.getString("dbUsername");
String sJdbcPwd = m_oJbProp.getString("dbPassword");
try {
if (m_oJbProp.getString("useConnectionPooling").equals("true")) {
if (log.isDebugEnabled()) {
log.debug("ConnectionPooling true");
if(null == m_ds) {
m_ds = setupDataSource(sJdbcDriver,sJdbcUrl,sJdbcUser,sJdbcPwd);
if (log.isDebugEnabled()) {
log.debug("DataSource created");
result = m_ds.getConnection();
} else {
// No connection pooling:
if (log.isDebugEnabled()) {
log.debug("ConnectionPooling false");
try {
Class.forName(sJdbcDriver);
result = DriverManager.getConnection(sJdbcUrl, sJdbcUser, sJdbcPwd);
} catch (ClassNotFoundException cnf) {
log.error("Exception: Class Not Found. ", cnf);
System.exit(0);
(.. ErrorHandling ...)Here is the code fragment which is doing the work:
StringBuffer sb = new StringBuffer();
while (lNextBottom <= lNextCeiling) {
con = getConnection();
innerSelStmt = con.prepareStatement("SELECT Hictgid, Hictgname FROM HIERARCHYCATEGORY WHERE HICTGID = ?");
innerSelStmt.setLong(1, lNextBottom);
rsInner = innerSelStmt.executeQuery();
if ((rsInner != null) && (rsInner.next())) {
sb.append(rsInner.getLong(1) + ", " + rsInner.getString(2) + "\r");
if (log.isDebugEnabled()) {
log.debug("Inner Statement: " + rsInner.getLong(1) + "\r");
rsInner.close();
con.close();
lNextBottom++;
if (log.isInfoEnabled()) {
log.info("\rResult values: Hictgid, Hictgname \r");
log.info(sb.toString());
}and the main method:
public static void main(String[] args) {
try {
long lStartTime = System.currentTimeMillis();
JdbcBasic oJb = new JdbcBasic();
boolean bSuccess = false;
bSuccess = oJb.getHierarchycategories();
if (log.isInfoEnabled()) {
log.info("Running time: " + (System.currentTimeMillis() - lStartTime));
if (null != m_ds) {
printDataSourceStats(m_ds);
shutdownDataSource(m_ds);
if (log.isInfoEnabled()) {
log.info("Datasource closed.");
} catch (SQLException sqe) {
log.error("SQLException within main-method", sqe);
}My database values are
databaseConnection=jdbc:oracle:thin:@SERVERDB:1521:ora
jdbcDriver=oracle.jdbc.driver.OracleDriver
databaseConnection=jdbc:jtds:sqlserver://SERVERDB:1433/testdb
jdbcDriver=net.sourceforge.jtds.jdbc.Driver
databaseConnection=jdbc:mysql://localhost/testdb
jdbcDriver=com.mysql.jdbc.Driver
dbUsername=testusr
dbPassword=testpwdThanks for your reading and maybe for your help.A few comments.
There is of course another difference between your test cases then just the database. There is also the driver. And I suspect that in at least the case with the jtds driver it is helping you along where you are doing something silly and the Oracle driver is not.
Before I explain the next part I would say the speed differences between MS-SQL and MySQL look about right I think you are aiming here for MS-SQL level performance not MySQL. (For a bunch of reasons MySQL is inherently faster but there are MANY drawbacks as well which have been well discussed on previous threads)
Here is where I believe your problem lies
while (lNextBottom <= lNextCeiling) {
con = getConnection();
innerSelStmt = con.prepareStatement("SELECT Hictgid, Hictgname FROM HIERARCHYCATEGORY WHERE HICTGID = ?");
innerSelStmt.setLong(1, lNextBottom);
rsInner = innerSelStmt.executeQuery();
if ((rsInner != null) && (rsInner.next())) {
sb.append(rsInner.getLong(1) + ", " + rsInner.getString(2) + "\r");
if (log.isDebugEnabled()) {
log.debug("Inner Statement: " + rsInner.getLong(1) + "\r");
rsInner.close();
con.close();
lNextBottom++;
}There at least four things that are wrong with above.
1) Why are you preparing the statement INSIDE the loop. Let us for a moment say that the loop will spin 100 times. That means that you are preparing the same statement 100 times. This is bad. It is also very relevant because for example the Jtds driver is going to be caching the prepared statements you make so that actually while you try and prepare it 100 times it only actually does it once... but in Oracle I don't know what it is doing for sure but if it is preparing on each pass well than that bit of it is going take 100 times longer then it should.
2) You are opening and closing the connection on each pass through the loop... also a terrible idea. You need to fix this first so that you can repeatedly use the same prepared statement.
3) Why are you looping in the first place? More on this later.
4) Where do you close the PreparedStatement? It doesn't look like you do.
Okay so for starters your loop should look a lot more like this...
code]
con = getConnection();
innerSelStmt = con.prepareStatement("SELECT Hictgid, Hictgname FROM HIERARCHYCATEGORY WHERE HICTGID = ?");
while (lNextBottom <= lNextCeiling) {
innerSelStmt.setLong(1, lNextBottom);
rsInner = innerSelStmt.executeQuery();
if ((rsInner != null) && (rsInner.next())) {
sb.append(rsInner.getLong(1) + ", " + rsInner.getString(2) + "\r");
rsInner.close();
lNextBottom++;
innerSelStmt.close();
con.close();
I think the code above (and you can put your debug stuff back if you want) which uses ONE connection and ONE prepared Statement will improve your performance dramatically.
The other question though I would as is why in the hell you are doing 100 or whatever number of queries anyway. This can be done all in ONE query which again will improve performance.
Your query and such should look like this I think.
String sql = "SELECT Hictgid, Hictgname FROM HIERARCHYCATEGORY WHERE HICTGID >=? AND HICTGID<=?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setLong(1,lNextBottom );
ps.setLong(2,lNextCeiling);
ResultSet rs = ps.executeQuery();
while(rs.next()){
// your appending to string buffer code goes here
}and I can't understand why you're not doing that in the first place. -
i have writen a DBTester.java to test connection pooling.
when i run my program , every time it open a new connection ?
please help me where i did mistake ?
package db;
import oracle.jdbc.pool.OracleConnectionPoolDataSource;
* @author Jayaraj
public class DBTester {
private static void test() throws Exception {
OracleConnectionPoolDataSource ocpds = new OracleConnectionPoolDataSource();
ocpds.setURL("jdbc:oracle:thin:@127.0.0.1:1521:db1");
ocpds.setUser("root");
ocpds.setPassword("root");
for (int i = 0; i < 100; i++) {
new RequestThread(i, ocpds).start();
public static void main(String[] args) throws Exception {
test();
package db;
import java.sql.Connection;
import java.sql.SQLException;
import javax.sql.PooledConnection;
import oracle.jdbc.pool.OracleConnectionPoolDataSource;
* @author Jayaraj
public class RequestThread extends Thread implements Runnable {
private OracleConnectionPoolDataSource datasource = null;
private int rid = 0;
public RequestThread(int rid, OracleConnectionPoolDataSource datasource) {
this.datasource = datasource;
this.rid = rid;
public void run() {
try {
PooledConnection pc = datasource.getPooledConnection();
Connection conn = pc.getConnection();
System.out.println(" Request ID :" + rid + " Connection : " + conn);
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}I have tested few properties . this will be helpfull
thanks for all ur reply
package db.test;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;
import org.apache.commons.dbcp.DelegatingCallableStatement;
import oracle.jdbc.driver.OracleCallableStatement;
import oracle.jdbc.driver.OracleResultSet;
import oracle.jdbc.driver.OracleTypes;
import oracle.jdbc.pool.OracleConnectionCacheManager;
import oracle.jdbc.pool.OracleDataSource;
* @author Jayaraj
public class DBTester {
public static void main(String[] args) throws Exception {
OracleDataSource datasource = new OracleDataSource();
datasource.setDataSourceName("oracle.jdbc.pool.OracleDataSource");
datasource.setURL("jdbc:oracle:thin:@10.187.53.10:1521:TEST");
datasource.setUser("wnr");
datasource.setPassword("wnr");
//enable the cache
datasource.setConnectionCachingEnabled(true);
Properties cacheProperties = new Properties();
cacheProperties.setProperty("MinLimit", "2");
cacheProperties.setProperty("MaxLimit", "5");
cacheProperties.setProperty("InitialLimit", "3");
//cacheProperties.setProperty("MaxStatementsLimit", "1");
cacheProperties.setProperty("InactivityTimeout", "10");
//cacheProperties.setProperty("TimeToLiveTimeout", "");
cacheProperties.setProperty("AbandonedConnectionTimeout", "1");
//cacheProperties.setProperty("ConnectionWaitTimeout", "");
//cacheProperties.setProperty("PropertyCheckInterval", "");
//cacheProperties.setProperty("ValidateConnection", "");
//cacheProperties.setProperty("ClosestConnectionMatch", "");
//cacheProperties.setProperty("AttributeWeights", "");
//cacheProperties.setProperty("LowerThresholdLimit", "");
datasource.setConnectionCacheProperties(cacheProperties);
System.out.println("testing initial limit");
testInitialLimit(datasource);
System.out.println("testing max limit");
testMaxLimit(datasource);
private static void testMaxLimit(OracleDataSource datasource) throws SQLException {
String max = (String)datasource.getConnectionCacheProperties().get("MaxLimit");
int maxi = Integer.parseInt(max);
for (int i = 0; i < maxi ; i++) {
//new TestThread(i,datasource).start();
Connection conn =datasource.getConnection();
System.out.println(i);
System.out.println("waiting for existing to close....");
Connection conn =datasource.getConnection();
System.out.println("maximum connection reached.."+conn);
static void showDetails() throws SQLException{
OracleConnectionCacheManager sConnectionCacheMananger = OracleConnectionCacheManager.getConnectionCacheManagerInstance();
String string[] = sConnectionCacheMananger.getCacheNameList();
for (int i = 0; i < string.length; i++) {
//System.out.println(string);
System.out.println("AvailableConnections : "+sConnectionCacheMananger.getNumberOfAvailableConnections(string[i]));
System.out.println("ActiveConnections : "+sConnectionCacheMananger.getNumberOfActiveConnections(string[i]));
private static void testInitialLimit(OracleDataSource datasource ) throws SQLException {
Connection conn =datasource.getConnection();
showDetails();
conn.close(); -
Configuring JCo3 Connection Pool with single sign on on non SAP Java server
Hi Everyone,
i have configured a connection pool on JBoss as per JCo3 Documentation and is working great.
Now I need help to configure this connection pool with single sign on so that RFc on SAP ECC systems are executed using end users credential rather than using single user name password used to configure JCo connection pool.
On SAP Java stack I am sure its possible within Java WebDynpro and i assume using JCA resource adapter. But what if we don't want to use SAP Java App server.
Any help will be appreciated.
Thanks,
Divyakumar JainEason, 你好！
I have exactly the same problem. Did you find a solution to this problem? If so, please let me know! -
Java Connection Pooling issue with Oracle 10g Express Edition
Hello
I have a Java based web application that uses the Oracle 10g Express Edition database. I am using a connection pool to get connections to the database.
I use the NetBeans IDE and run my web application on the bundled Tomcat server(5.5.7) that comes with the IDE. Though when I initially run the application from the IDE, the connection pool is set up fine, when I recompile my java code and try to run the application again, I get the following error each time:
Listener refused the connection with the following error:
ORA-12516, TNS:listener could not find available handler with the
matching protocol stack.
The logs before the error shows up, indicate that the connection pool object is fine and gives me the number of available connections and the number of active connections and so on, which I have printed from the constructor of the Connection Pool class:
For e.g.:
Cache size = 17
Available Connections = 17
Cache Limit = 1000
Active size = 0
However, if I kill my Tomcat server process and run the application again, it works fine with no error.
I looked around for possible causes and solutions and all I could find
was increasing the processes parameter value in the init.ora file. I have increased the parameter value to from 100 to 20000 now, in increments of 500/1000 each time but it hasnt worked so far.
Someone else suggested that I increase the size of my connection pool; I initially had it set to a minimum limit of 5, an initial limit of 10 and a maximum limit of 1000. However if I set the Initial Limit to anything above 17 connections, I see the following log on the Bundled Tomcat log and my application doesn't run at all:
Log: Loading JDBC Driver : class=oracle.jdbc.driver.OracleDriver ...
Log: Loaded JDBC Driver
Log: Connection with URL=jdbc:oracle:thin:@localhost:1521:xe as username/password
Error code not handled : 0
Exception Message :java.sql.SQLException: Listener refused the connection with the following error:
ORA-12519, TNS: no appropriate service handler found
The Connection descriptor used by the client was:
localhost:1521:xe
// End of log
And the Bundled Tomcat server automatically shuts down.
Again the System.out statements from the Connection Pool class constructor show that the cache has been initialized and that currently there are free connections available in the pool.
E.g.
Cache size = 18
Available Connections = 18
Cache Limit = 1000
Active size = 0
Has anyone faced anything similar? Could someone please suggest what I'm doing wrong here and what I should do to set right this problem?
Swethahello, please pardon me, my english is basic. i do of my best. i had the same problem until reading the pdf documentation 2 days for java devvelloper.it is simple, follow this way.
try {OracleDataSource ds;
Connection conn;
ds = new OracleDataSource();
ds.setURL("jdbc:oracle:thin:@localhost");
conn = ds.getConnection("userid","password");
Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
don't forget to Dowload the user client of oracle Express Edition. do the rest of your program and it will work. take a look to the documentation pdf for java develloper. all it is explained. good look -
How to Create a connection pool in OSB java callout
Dear Team,
In our project, we need read some data from DB, and do corresponding operation. currently, we need setup the connection first, execute the SQL, and close the connection.
But the concurrency of call is very high, is there a way to create a connection pool, then we can use the connection pool to get the connection and execute the SQL, then return the connection to the pool.
if connection pool is not available, is there any way to create the connection outside the java callout, that we can just execute the SQL in java callout.
The OSB version is 11.1.1.6.0
Thanks.
Best Regards,
Raysen Jia
Edited by: Raysen Jia on Oct 16, 2012 8:44 AMHi Team,
Thanks for your help.
What I need is not only the db connection, may be other kind of things, such as read configuration from file...
If I write the code in java callout with static java method to create and close the connection, each time when request come in, OSB will create a new connection (or read the file), I think it's not the best practice to do this kind of work.
I think the weblogic is running in JVM, is there any way we can define variables or new object in the JVM directly? -
Connection Pooling in Core Java Application
I need to implement Connection pooling in core java applications..
My database is MySQL 5.0.27 and java version 1.5.0_09
Any links or ideas will be really appreciatedbut i just wanted to know, how can i do that in core java application. i have used connection pooling in Tomcat using dbcp
but these are my questions.
1. How can i run a core java application doing TCP connection in an Application Server which has got Tomcat and i'm asked to do connection pooling in the Tomcat server.xml.. I didn't understand this requirement pls help me... plssssssssssss -
How to compile connection pool sample java code
I recently bought David Knox's "Effective Oracle Database 10g Security by Design", and have been working through his examples with client identifiers and how to leverage database security with anonymous connection pools.
The database side of things I totally understand and have set up, but I now want to compile/run the java code examples, but don't know what is required to compile this.
I'm running Oracle 10.2.0.4 (64-bit) Enterprise Edition on a Linux (RHEL 5) PC. Java version is 1.6.0_20. Relevant .bash_profile environment variables are as follows:
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/jre:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
export PATH=$ORACLE_HOME/bin:$ORACLE_HOME/OPatch:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin
When I try to compile, I get:
oracle:DB10204$ java FastConnect.java
Exception in thread "main" java.lang.NoClassDefFoundError: FastConnect/java
Caused by: java.lang.ClassNotFoundException: FastConnect.java
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: FastConnect.java. Program will exit.
The java source code of one of the examples is below. Is someone able to point me in the right direction as to how I get this to compile? Do I just have a syntax and/or environment configuration modification to do, or is there more to it than that to get this example working? Any help much appreciated.
oracle:DB10204$ cat FastConnect.java
package OSBD;
import java.sql.*;
import oracle.jdbc.pool.OracleDataSource;
public class FastConnect
public static void main(String[] args)
long connectTime=0, connectionStart=0, connectionStop=0;
long connectTime2=0, connectionStart2=0, connectionStop2=0;
ConnMgr cm = new ConnMgr();
// time first connection. This connection initializes pool.
connectionStart = System.currentTimeMillis();
Connection conn = cm.getConnection("SCOTT");
connectionStop = System.currentTimeMillis();
String query = "select ename, job, sal from person_view";
try {
// show security by querying from View
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery(query);
while (rset.next()) {
System.out.println("Name: " + rset.getString(1));
System.out.println("Job: " + rset.getString(2));
System.out.println("Salary: " + rset.getString(3));
stmt.close();
rset.close();
// close the connection which resets the database session
cm.closeConnection(conn);
// time subsequent connection as different user
connectionStart2 = System.currentTimeMillis();
conn = cm.getConnection("KING");
connectionStop2 = System.currentTimeMillis();
// ensure database can distinguish this new user
stmt = conn.createStatement();
rset = stmt.executeQuery(query);
while (rset.next()) {
System.out.println("Name: " + rset.getString(1));
System.out.println("Job: " + rset.getString(2));
System.out.println("Salary: " + rset.getString(3));
stmt.close();
rset.close();
cm.closeConnection(conn);
} catch (Exception e) { System.out.println(e.toString()); }
// print timing results
connectTime = (connectionStop - connectionStart);
System.out.println("Connection time for Pool: " + connectTime + " ms.");
connectTime2 = (connectionStop2 - connectionStart2);
System.out.println("Subsequent connection time: " +
connectTime2 + " ms.");
}Code download is at: http://www.mhprofessional.com/getpage.php?c=oraclepress_downloads.php&cat=4222
I'm looking at Chapter 6.stuartu wrote:
When I try to compile, I get:
oracle:DB10204$ java FastConnect.java
Exception in thread "main" java.lang.NoClassDefFoundError: FastConnect/java
Caused by: java.lang.ClassNotFoundException: FastConnect.java
I will try to explain what is happening here.
You are launching java telling it to run a class named 'java' in a package named 'FastConnect'
and java says it cannot find that class.
What you intended to do:
$ # make the directory structure match the package structure
$ mkdir OSBD
$ # move the source file in the directory structure so it matches the package structure
$ mv FastConnect.java OSBD/
$ # compile OSBD/FastConnect.java to OSBD/FastConnect.class
$ javac OSBD/FastConnect.java
$ # launch java using the OSBD/FastConnect class
$ java -cp . OSBD.FastConnectNote that the package 'OSBD' does not follow the recommended naming conventions
you might consider changing that to 'osbd'. -
Regarding connection pooling in java mail
Hi,
Im implementing enterprise application which has ability of sending/receiving emails. Im using java mail API 14.3. I have implemented the application level connection pooling which keep track of open folders, perform the time-out and other tasks. The connection pooling setting of IMAPStore is default setting. When we run our application in high load we get StoreClosedExcepton (Socket closed exception). My assumption is that when we perform some operation on folder, java mail also sends the noop command for store connection so there is no chance of store getting timeout.
Is there anything wrong in my understanding?JavaMail does not do anything to keep the connection "alive". Servers are free to close
connections that have been unused for too long (usually 30 minutes). If you need to
keep the connection alive, you'll need to do some operation periodically, such as checking
the number of messages in the folder. Even that doesn't guard against server or network
failures, of course, so you always have to be prepared for a StoreClosedException or
FolderClosedException. -
Set up DB Connection Pool for Oracle DataBase Using Java App Server8
Hi,
In the Admin Console of Java App Server 8, I tried to create a connection pool for the oracle database. I chose Resource Type to be "javax.sql.ConnectionPoolDataSource" and the Vendor is Oracle. So the Data Source Class Name is filled by the system to be "oracle.jdbc.pool.OracleConnectionPoolDataSource". Now, I set up the class path to point to the database driver class "sun.jdbc.odbc.JdbcOdbcDriver" and also the to the Data Source Class Name. Also I set up the JVM options in the console. Restart the server, and then try to ping to the database, but get the error:
Operation 'pingConnectionPool' failed in 'resources' Config Mbean. Target exception message: Connection could not be allocated because: No suitable driver
I don't understand what else I should do and why this error is coming?
Please help me out.
Thank you
Regards,
SarahHi,
I've already solve the problem. I did the following:
set the Url to be: jdbc:oracle:thin:@hostname:port:SID
set username
set password
add oracle.jdbc.drivers.OracleDriver into the JVM options -Djdbc.drivers
restart the server
test the connection
it works :) -
How can I implement the connection pool in my java stored procedure
my java stored procedures (in database 'B') have to connect to another oracle database ,let's say 'A'. And how can I implement the behavior like the so-called connection pool in my java stored procedure in 'B', as below.
1. database B, has 2 java stored procedures sp1 and sp2
2. both sp1 and sp2 connects to databse 'A'
whatever I call the sp1 and sp2 and the database 'A' always only one connected session from sp1 and sp2 in database 'B'.
THANKS A LOTS...my problem is I have a lots of java stored procedures need to cnnect to the remote oracle db, and I hope the remote db can only have a connected session from my java stored procedures in my local db. I try as below
class sp{
static Connection conn=null; //the remote db connection,
public static void sp1(){...}//procedure 1, using conn
public static void sp2(){...}//procedure 2, using conn,too
I can 'see' the 'conn' variable if I invoke the sp1() and sp2() from the same client application(maybe sqlplus). But if I invoke the sp1() from client 'A' and invoke sp2() from client 'B' then the sp1() and sp2() can not see the 'conn' variable for each other. I think it's because the two clients cause oracle to create two instances of the class 'sp' and the sp1() and sp2() located in different instance seperately. Thus the sp1() and sp2() can not see 'conn' for each other. They can only see its own 'conn'.
To connect to the remote db from the java stored procedure is easy but is it possible to connect to the remote db via database link from the java stored procedure at my local db ? If so, then I also archive my goal .
BTW , thanks a lots...
andrew :-) -
How to make Connection Pooling in JAVA
Dear Members
I want to know that how can i make connection pooling in java and also how can i use that pool in my jsp/servlet application.
Plz Describe in Detail.
Thanks
Vasimvasim_saiyad2000 wrote:
Dear Members
I want to know that how can i make connection pooling in java and also how can i use that pool in my jsp/servlet application.
Plz Describe in Detail.
Thanks
VasimAs the previous poster is trying to suggest, the server you use will have datasource and connection pooling support. so look up in the manual how to set it up, or do a google search. For example if you use Tomcat, look here:
http://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto.html -
Java Pet Store and connection pooling
Hi. Does the Java Petstore version 1.2 use connection pooling? I know in the database.properties file it has the following variables:
Pool.MaximumActiveConnections=10
Pool.MaximumIdleConnections=5
Pool.MaximumCheckoutTime=120000
Pool.TimeToWait=10000
Pool.PingEnabled=false
Pool.PingQuery=select * from dual
Pool.PingConnectionsOlderThan=0
Pool.PingConnectionsNotUsedFor=0
Pool.QuietMode=true
To me this seems like it is using connection pooling. However, on our server, we are continually running out of connections and I KNOW that our other apps ARE using connection pooling. So I'm just wondering if someone can confirm with me that the Java Pet Store is in fact using connection pooling.
Thanks in advance,
DylanI forgot to mention that I'm using the Ibatis version of the JPetstore.
-
I want to know what is the procedure of getting oracle's jdbc connection pooling api(class files and java doc).
I also want to know whether it is free or notftp://javaexchange.com/javaexchange/DbConnectionBroker1.0.13.tar
from http://javaexchange.com/ by Mark Mnich
Initialise the pool in a startupservlet, place a reference to it in the servlet context (ServletContext.setAttribute(String name, Object myDbPool))
This one is really easy to use and very efficient indeed (endorsed by author David Harms).
It doesn't support multiple databases.
Maybe two pools would be just as effective? The whole point of a connection pool is that the connections within it are constantly open... so you would still have (for example) 25 connections to one database and 25 to the other - constantly. Making unused connections disconnect and connect to the other database would defeat the point, each servlet instance may as well establish its own connection So why not have two pools???
Bamkin
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