Quartz is a full-featured, open source job scheduling service that can be integrated with, or used along side
virtually any Java EE or Java SE application – from the smallest stand-alone application to the largest
e-commerce system. Quartz can be used to create simple or complex schedules for executing tens, hundreds,
or even tens-of-thousands of jobs; jobs whose tasks are defined as standard Java components that are
programmed to fulfill the requirements of your application. The Quartz Scheduler includes many
enterprise-class features, such as JTA transactions and clustering.

Many organization and frameworks are using Quartz, Jboss, Spring, and Luntbuild, Quartz Scheduler is licensed under the Apache License, Version 2.0 http://www.quartz-scheduler.org/overview/license-and-copyright

And here is a introduction of CronTrigger: http://www.quartz-scheduler.org/documentation/quartz-2.1.x/tutorials/crontrigger

How to set the cron expression in Luntbuild: http://luntbuild.javaforge.com/manual/guide/ch14s02.html

Here are some full examples:

**Expression**	**Meaning**
0 0 12 * * ?	Fire at 12pm (noon) every day
0 15 10 ? * *	Fire at 10:15am every day
0 15 10 * * ?	Fire at 10:15am every day
0 15 10 * * ? *	Fire at 10:15am every day
0 15 10 * * ? 2005	Fire at 10:15am every day during the year 2005
0 * 14 * * ?	Fire every minute starting at 2pm and ending at 2:59pm, every day
0 0/5 14 * * ?	Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day
0 0/5 14,18 * * ?	Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day
0 0-5 14 * * ?	Fire every minute starting at 2pm and ending at 2:05pm, every day
0 10,44 14 ? 3 WED	Fire at 2:10pm and at 2:44pm every Wednesday in the month of March.
0 15 10 ? * MON-FRI	Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday
0 15 10 15 * ?	Fire at 10:15am on the 15th day of every month
0 15 10 L * ?	Fire at 10:15am on the last day of every month
0 15 10 L-2 * ?	Fire at 10:15am on the 2nd-to-last last day of every month
0 15 10 ? * 6L	Fire at 10:15am on the last Friday of every month
0 15 10 ? * 6L	Fire at 10:15am on the last Friday of every month
0 15 10 ? * 6L 2002-2005	Fire at 10:15am on every last friday of every month during the years 2002, 2003, 2004 and 2005
0 15 10 ? * 6#3	Fire at 10:15am on the third Friday of every month
0 0 12 1/5 * ?	Fire at 12pm (noon) every 5 days every month, starting on the first day of the month.
0 11 11 11 11 ?	Fire every November 11th at 11:11am.

Pay attention to the effects of ‘?’ and ‘*’ in the day-of-week and day-of-month fields!

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<tstamp>
            <format property="today" pattern="yyyy_MM_dd_HH_mm"/>
        </tstamp>
<echo message="${today}"></echo>

[echo] 2012_03_22_23_00

Tstamp in Ant manual:

http://ant.apache.org/manual/Tasks/tstamp.html

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Step2: enlarge table space file
alter database datafile 'C:\ORACLEXE\APP\ORACLE\ORADATA\XX\USERS.DBF' resize 2000m;

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select to_char(sysdate, 'yyyy-mm-dd hh24:mi:ss') from dual; -- Get the formatted system date.
select sysdate from dual; -- Get date

Count user tables:

SELECT OWNER,COUNT(*) FROM ALL_TABLES GROUP BY OWNER;  -- List all user and table number they own;

select count(*) from dba_tables t where t.owner='NAME'; -- Count tables of user with the name of "NAME"
select count(table_name) from user_tables; -- Count tables of current user;

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oracle.dbtools.raptor.timesten.TTAddin
Failed to create addin oracle.dbtools.raptor.report.addin.ReportAddin

I removed all data,  but cannot work as before, based on my research, I think it’s because the SQL Developper is too old.

so I download a new version of SQL Developper, and it works!

For more info about this issue: https://forums.oracle.com/forums/message.jspa?messageID=9491523

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but as a user, when click “Edit” or “Create”, “Save as” window will pop up, but a guest can create/edit page using the Editor.

After post a discussion on the support desk of MediaWiki: http://www.mediawiki.org/wiki/Project:Support_desk;

the solution is:

Disable “use external editor” in your preferences.

by Max Semenik

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Can’t clobber writable file Perforce

Here is the solution:

“A workaround is to stop perforce from making the files read-only on submit. This can be accomplished by changing the Client Specification and setting the “allwrite” flag. This way the files never go to readonly mode and you should be able to write to it always.”

>>See more<<

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After connect to the server as sys admin, execute the following SQL:
begin
dbms_xdb.sethttpport(’8888′);
end;
/

The port will be updated to 8888, no need to restart the oracle service.

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闲言碎语不多说, 上代码:

DatastoreService datastoreService = DatastoreServiceFactory.getDatastoreService();
		Query query = new Query("User");
		query.addFilter("name", FilterOperator.NOT_EQUAL, ""); // 设置Filter
		query.addSort("name", SortDirection.ASCENDING); // 要设置Sort, 则Filter的Attribute必须Sort, 且要放在其他Sort之前(Attribute要Index)
		query.addSort("ip", SortDirection.DESCENDING); // 设置Sort, 要在Filter对应Attribute的Sort之后
		PreparedQuery pq = datastoreService.prepare(query);
		List listUsers = pq.asList(FetchOptions.Builder.withLimit(2)); // 设置Limit

Properties in Inequality Filters Must Be Sorted before Other Sort Orders

If a query has both a filter with an inequality comparison and one or more sort orders, the query must include a sort order for the property used in the inequality, and the sort order must appear before sort orders on other properties.

This query is not valid, because it uses an inequality filter and does not order by the filtered property;

文档: http://code.google.com/appengine/docs/java/datastore/queries.html#Restrictions_on_Queries

翻不了墙的同学可以看这个 – 主要是分页: 

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.google.appengine.api.datastore.Cursor;
import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.FetchOptions;
import com.google.appengine.api.datastore.PreparedQuery;
import com.google.appengine.api.datastore.Query;
import com.google.appengine.api.datastore.QueryResultList;

public class ListPeopleServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
          throws ServletException, IOException {

        DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
        Query q = new Query("Person");
        PreparedQuery pq = datastore.prepare(q);
        int pageSize = 15;

        resp.setContentType("text/html");
        resp.getWriter().println("
");

        FetchOptions fetchOptions = FetchOptions.Builder.withLimit(pageSize);
        String startCursor = req.getParameter("cursor");

        // If this servlet is passed a cursor parameter, let's use it
        if (startCursor != null) {
            fetchOptions.startCursor(Cursor.fromWebSafeString(startCursor));
        }

        QueryResultList results = pq.asQueryResultList(fetchOptions);
        for (Entity entity : results) {
            resp.getWriter().println("
" + entity.getProperty("name") + "");
        }
        resp.getWriter().println("


");

        String cursor = results.getCursor().toWebSafeString();

        // Assuming this servlet lives at '/people'
        resp.getWriter().println(
            "Next page");
    }
}

关于分页的另一篇:

Implementing Paging on Google App Engine Java (gae/j) and GWT — the query cursor way

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Java版的cron.xml配置文件位于WEB-INFO目录下(位置同web.xml), 典型的一个:

<?xml version=”1.0″ encoding=”UTF-8″?>
<cronentries>
  <cron>
    <url>/GetIPLocation</url>
    <description>get the ip location by api every 2 minutes</description>
    <schedule>every 2 minutes</schedule>
  </cron>
</cronentries>

该任务每两分钟执行一次, GepIPLocation是一个Servlet.

时间格式举例:

every 12 hours
every 5 minutes from 10:00 to 14:00
2nd,third mon,wed,thu of march 17:00
every monday 09:00
1st monday of sep,oct,nov 17:00
every day 00:00

API地址: http://code.google.com/appengine/docs/java/config/cron.html (可能需要翻墙)

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