SQL錯誤信息
1、無效的描述符索引
解決辦法:數據庫表里字段是按什么順序排的,程序也按什么順序讀。
2、無效的游標狀態
可能的解決辦法:用ResultSet讀數據前要先調用resultSet.next();
e文請參考:http://www.linuxcommand.org/lts0080.php
Linux下使用Shell命令控制任務(Jobs)執行
下列命令可以用來操縱進程任務:
ps 列出系統中正在運行的進程
kill 發送信號給一個或多個進程(經常用來殺死一個進程)
jobs 列出屬于當前用戶的進程
bg 將進程搬到后臺運行(Background)
fg 將進程搬到前臺運行(Foreground)
將job轉移到后臺運行
如果你經常在X圖形下工作,你可能有這樣的經歷:通過終端命令運行一個GUI程序,GUI界面出來了,但是你的終端還停留在原地,你不能在shell中繼續執行其他命令了,除非將GUI程序關掉。
為了使程序執行后終端還能繼續接受命令,你可以將進程移到后臺運行,使用如下命令運行程序: #假設要運行xmms
$xmms &
這樣打開xmms后,終端的提示又回來了。現在xmms在后臺運行著呢(可以繼續工作和聽音樂了^_^)
但萬一你運行程序時忘記使用“&”了,又不想重新執行(Eclipse啟動速度太慢了,我不想重啟啊,:))。你可以先使用ctrl+z掛起程序,然后敲入bg命令,這樣程序就在后臺繼續運行了。
察看jobs
使用jobs或ps命令可以察看正在執行的jobs。(the two have a little diff. have a try ^_^)
kill a job
方法一:
通過jobs命令查看job號(假設為num),然后執行kill %num
方法二:
通過ps命令查看job的進程號(PID,假設為pid),然后執行kill pid
kill的其他作用
kill除了可以終止進程,還能給進程發送其它信號,使用kill -l 可以察看kill支持的信號。
SIGTERM是不帶參數時kill發送的信號,意思是要進程終止運行,但執行與否還得看進程是否支持。如果進程還沒有終止,可以使用kill -SIGKILL pid,這是由內核來終止進程,進程不能監聽這個信號。
下期預告:Writing shell scripts(跟我寫Shell腳本)
e文請參考:http://www.linuxcommand.org/lts0080.php
Linux下使用Shell命令控制任務(Jobs)執行
下列命令可以用來操縱進程任務:
ps 列出系統中正在運行的進程
kill 發送信號給一個或多個進程(經常用來殺死一個進程)
jobs 列出屬于當前用戶的進程
bg 將進程搬到后臺運行(Background)
fg 將進程搬到前臺運行(Foreground)
將job轉移到后臺運行
如果你經常在X圖形下工作,你可能有這樣的經歷:通過終端命令運行一個GUI程序,GUI界面出來了,但是你的終端還停留在原地,你不能在shell中繼續執行其他命令了,除非將GUI程序關掉。
為了使程序執行后終端還能繼續接受命令,你可以將進程移到后臺運行,使用如下命令運行程序: #假設要運行xmms
$xmms &
這樣打開xmms后,終端的提示又回來了。現在xmms在后臺運行著呢(可以繼續工作和聽音樂了^_^)
但萬一你運行程序時忘記使用“&”了,又不想重新執行(Eclipse啟動速度太慢了,我不想重啟啊,:))。你可以先使用ctrl+z掛起程序,然后敲入bg命令,這樣程序就在后臺繼續運行了。
察看jobs
使用jobs或ps命令可以察看正在執行的jobs。(the two have a little diff. have a try ^_^)
kill a job
方法一:
通過jobs命令查看job號(假設為num),然后執行kill %num
方法二:
通過ps命令查看job的進程號(PID,假設為pid),然后執行kill pid
kill的其他作用
kill除了可以終止進程,還能給進程發送其它信號,使用kill -l 可以察看kill支持的信號。
SIGTERM是不帶參數時kill發送的信號,意思是要進程終止運行,但執行與否還得看進程是否支持。如果進程還沒有終止,可以使用kill -SIGKILL pid,這是由內核來終止進程,進程不能監聽這個信號。
下期預告:Writing shell scripts(跟我寫Shell腳本)
名詞
Ubuntu 團隊免費給你郵寄 Ubuntu 光盤,你可以用來安裝或者分享給其他人。 我們會承擔這些光盤的貨運費用。
The link address is: http://shipit.ubuntulinux.org/
鏈接
Ubuntu 團隊免費給你郵寄 Ubuntu 光盤,你可以用來安裝或者分享給其他人。 他們會承擔這些光盤的貨運費用。
在此填寫你的郵寄地址: http://shipit.ubuntulinux.org/
jorgeOct 26, 2005- Show original item
Have you ventured beyond Ubuntu’s default GNOME desktop applications? There’s a wealth of great tools available in the Ubuntu repositories. The Universe is a huge place, and it’s easy to get overwhelmed by the amount of software available. But don’t worry, because Jorge ‘whiprush’ Castro will pilot our guided tour of universe applications that will make you fall in love with Ubuntu all over again. Whether you’re an experienced user or brand new to Linux, there’s always new hidden gems in Ubuntu waiting to be discovered.
Pre-flight Checklist
Universe is composed of packages from Debian that aren’t fully supported by Ubuntu. But we need not worry - the MOTU team of over 30 developers ensures these packages build and work, and they’re very responsive to bug reports.
Universe requires some manual set up before being used. Luckily for us, our hard working ground crew (aka the Documentation Team) has already outlined the process for us. Once you’ve followed those steps, you’re ready to go.
Blast Off!
The deskbar-applet is a small multipurpose text box which sits in the panel. Typing in the box allows you to quickly search amazon.com, Google, wikipedia, yahoo, ebay, Creative Commons, and even Beagle. It also acts as an application launcher, allowing you to launch applications or open folders right from your panel. Fridge Tip: The default keyboard shortcut to use the applet is Alt-F3.
The Breezy release features two new applications that improve the Ubuntu laptop experience. GNOME Power Manager is an application which monitors and lets you control many power management features on modern laptops.
The NetworkManager tool provides an easy to use applet for controlling wireless interfaces. It features autoscanning, graphical control of which network to join, and Virtual Private Networking support for Cisco VPNs. This allows a user to click on the icon, see which networks are available, and then join one by clicking on the name of the network. It automatically gets an IP address and shows a graphical status icon. It also manages wired connections, so when a user plugs in an ethernet cable, NetworkManager will automatically configure the wired connection.
Both NetworkManager and gnome-power-manager are relatively new, so there are still instances where it might not work for you, but development on both tools is progressing rapidly, so if you have problems with these, make sure you revisit them when Ubuntu 6.04 is released.
Gobby is a small collaborative text editor that updates documents in real time. Think of it as a multi-user gEdit. One user starts a session as a host, creates or opens a document, and then the other users join that session. The bottom of the application has an IRC-like window for chatting, while the user-assigned colors allow the users to see who is making changes to which specific portions of the file.
Brightside is a tool for making “hot corners” on your desktop. You can assign different tasks to each corner; for example, you can configure it so that your screensaver activates when you move the mouse cursor to the bottom left corner. Fridge Tip: You can also make Brightside switch the workspace as you move the mouse to the edge of the screen.
Gajim is a Jabber client with a simple interface. It supports different icon themes and full support for using the user’s GPG key to encrypt instant messaging traffic. A built-in notification dialog the user of incoming instant messages. The included “Human” color theme also looks great on an Ubuntu desktop.
The Mono Galaxy
This part of the universe is well travelled, but we’ll do a quick flyby just in case. Tomboy is a simple applet that allows you to quickly take and organize notes. Tomboy automatically links text in a note to another note’s title as it’s being written, so as the user continues to make notes the application it becomes a self-referencing wiki-like repository of information. Clicking on the icon shows the recent edited notes and a search feature.
f-spot is a photo management application. It includes camera import support and exporting to Flickr, Gallery, or to CD-R/W. The GNOME Journal has a fairly complete introduction to f-spot.
Two newly forming stars, the Banshee music player (with iPod read and write support) and the famous Beagle desktop search are also available, but they’re still being developed, so we’ll have to check up on them next time.
Keep on Truckin’…
Monkey Bubble is a bust-a-move clone that is great for killing a few hours. The goal is to shoot a colored bubble at the stack of other colored bubbles near the top of the screen. When three bubbles of the same color come in contact, they explode. The goal is to clear the screen of bubbles before they fill up your screen. Fridge Tip: It supports up to 4 players with network play on a LAN, so set aside some time with your friends.
Here’s a program that we should have used before we left! Celestia is a space simulator, a “browser” for the solar system. It allows you to seamlessly move between heavenly bodies and explore the real universe in three dimensions.
glabels is a program for making printed labels. It has support for over 100 kinds of labels, just pick a template, insert the text, and print.
Manually trudging through art sites for nifty artwork can be a pain. gnome-art takes the hard work out of the process, by connecting to the art.gnome.org web service and letting you browse and download wallpapers right from the application itself.
Sometimes it’s just plain difficult to explain something to someone over the phone or via chat. Istanbul places a record button in your notification area. Clicking on it makes Istanbul record your desktop session as a video. After you’ve made your video, clicking on it again stops the recording and outputs the file as Ogg video. As you can see from the screenshot, it also supports streaming the video directly to an Icecast server.
The Trip Home
So, not a bad little journey. You’d be surprised what you can find if you go out and look for adventure, and we haven’t even scratched the surface of applications, so make sure you keep checking in so we can keep freewheeling through space. Feel free to contact me if you’ve found hidden nebula of desktop goodness and we’ll bring the ship on by.
jorgeOct 26, 2005?-? Show original item
Have you ventured beyond Ubuntu’s default GNOME desktop applications? There’s a wealth of great tools available in the Ubuntu repositories. The Universe is a huge place, and it’s easy to get overwhelmed by the amount of software available. But don’t worry, because Jorge ‘whiprush’ Castro will pilot our guided tour of universe applications that will make you fall in love with Ubuntu all over again. Whether you’re an experienced user or brand new to Linux, there’s always new hidden gems in Ubuntu waiting to be discovered.
Pre-flight Checklist
Universe is composed of packages from Debian that aren’t fully supported by Ubuntu. But we need not worry - the MOTU team of over 30 developers ensures these packages build and work, and they’re very responsive to bug reports.
Universe requires some manual set up before being used. Luckily for us, our hard working ground crew (aka the Documentation Team) has already outlined the process for us. Once you’ve followed those steps, you’re ready to go.
Blast Off!
The deskbar-applet is a small multipurpose text box which sits in the panel. Typing in the box allows you to quickly search amazon.com, Google, wikipedia, yahoo, ebay, Creative Commons, and even Beagle. It also acts as an application launcher, allowing you to launch applications or open folders right from your panel. Fridge Tip: The default keyboard shortcut to use the applet is Alt-F3.
The Breezy release features two new applications that improve the Ubuntu laptop experience. GNOME Power Manager is an application which monitors and lets you control many power management features on modern laptops.
The NetworkManager tool provides an easy to use applet for controlling wireless interfaces. It features autoscanning, graphical control of which network to join, and Virtual Private Networking support for Cisco VPNs. This allows a user to click on the icon, see which networks are available, and then join one by clicking on the name of the network. It automatically gets an IP address and shows a graphical status icon. It also manages wired connections, so when a user plugs in an ethernet cable, NetworkManager will automatically configure the wired connection.
Both NetworkManager and gnome-power-manager are relatively new, so there are still instances where it might not work for you, but development on both tools is progressing rapidly, so if you have problems with these, make sure you revisit them when Ubuntu 6.04 is released.
Gobby is a small collaborative text editor that updates documents in real time. Think of it as a multi-user gEdit. One user starts a session as a host, creates or opens a document, and then the other users join that session. The bottom of the application has an IRC-like window for chatting, while the user-assigned colors allow the users to see who is making changes to which specific portions of the file.
Brightside is a tool for making “hot corners” on your desktop. You can assign different tasks to each corner; for example, you can configure it so that your screensaver activates when you move the mouse cursor to the bottom left corner. Fridge Tip: You can also make Brightside switch the workspace as you move the mouse to the edge of the screen.
Gajim is a Jabber client with a simple interface. It supports different icon themes and full support for using the user’s GPG key to encrypt instant messaging traffic. A built-in notification dialog the user of incoming instant messages. The included “Human” color theme also looks great on an Ubuntu desktop.
The Mono Galaxy
This part of the universe is well travelled, but we’ll do a quick flyby just in case. Tomboy is a simple applet that allows you to quickly take and organize notes. Tomboy automatically links text in a note to another note’s title as it’s being written, so as the user continues to make notes the application it becomes a self-referencing wiki-like repository of information. Clicking on the icon shows the recent edited notes and a search feature.
f-spot is a photo management application. It includes camera import support and exporting to Flickr, Gallery, or to CD-R/W. The GNOME Journal has a fairly complete introduction to f-spot.
Two newly forming stars, the Banshee music player (with iPod read and write support) and the famous Beagle desktop search are also available, but they’re still being developed, so we’ll have to check up on them next time.
Keep on Truckin’…
Monkey Bubble is a bust-a-move clone that is great for killing a few hours. The goal is to shoot a colored bubble at the stack of other colored bubbles near the top of the screen. When three bubbles of the same color come in contact, they explode. The goal is to clear the screen of bubbles before they fill up your screen. Fridge Tip: It supports up to 4 players with network play on a LAN, so set aside some time with your friends.
Here’s a program that we should have used before we left! Celestia is a space simulator, a “browser” for the solar system. It allows you to seamlessly move between heavenly bodies and explore the real universe in three dimensions.
glabels is a program for making printed labels. It has support for over 100 kinds of labels, just pick a template, insert the text, and print.
Manually trudging through art sites for nifty artwork can be a pain. gnome-art takes the hard work out of the process, by connecting to the art.gnome.org web service and letting you browse and download wallpapers right from the application itself.
Sometimes it’s just plain difficult to explain something to someone over the phone or via chat. Istanbul places a record button in your notification area. Clicking on it makes Istanbul record your desktop session as a video. After you’ve made your video, clicking on it again stops the recording and outputs the file as Ogg video. As you can see from the screenshot, it also supports streaming the video directly to an Icecast server.
The Trip Home
So, not a bad little journey. You’d be surprised what you can find if you go out and look for adventure, and we haven’t even scratched the surface of applications, so make sure you keep checking in so we can keep freewheeling through space. Feel free to contact me if you’ve found hidden nebula of desktop goodness and we’ll bring the ship on by.