我目前正在使用Hadoop-2.0.3-alpha,之后我可以完美地使用HDFS(将文件复制到HDFS,从外部框架获得成功,使用webfrontend),在我的VM重新启动后,datanode进程正在停止过了一会儿.namenode进程和所有纱线进程都没有问题.我在另一个用户下的一个文件夹中安装了Hadoop,因为我还安装了Hadoop 0.2,它也运行良好.看一下所有datanode进程的日志文件,我得到了以下信息:

2013-04-11 16:23:50,475 WARN org.apache.hadoop.util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
2013-04-11 16:24:17,451 INFO org.apache.hadoop.metrics2.impl.MetricsConfig: loaded properties from hadoop-metrics2.properties
2013-04-11 16:24:23,276 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Scheduled snapshot period at 10 second(s).
2013-04-11 16:24:23,279 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: DataNode metrics system started
2013-04-11 16:24:23,480 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Configured hostname is user-VirtualBox
2013-04-11 16:24:28,896 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Opened streaming server at /0.0.0.0:50010
2013-04-11 16:24:29,239 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Balancing bandwith is 1048576 bytes/s
2013-04-11 16:24:38,348 INFO org.mortbay.log: Logging to org.slf4j.impl.Log4jLoggerAdapter(org.mortbay.log) via org.mortbay.log.Slf4jLog …

任何人都可以告诉我如何验证UITextFields内部UIAlertController？

除非输入两个字段,否则我需要它来阻止用户单击"保存".

到目前为止,这是我的代码:

@IBAction func btnStart(sender: AnyObject) {
    var alert = UIAlertController(title: "New user",
        message: "Add a new user",
        preferredStyle: .Alert)

    let saveAction = UIAlertAction(title: "Save",
        style: .Default) { (action: UIAlertAction!) -> Void in

            self.textFieldName = alert.textFields![0] as UITextField
            self.textFieldEmail = alert.textFields![1] as UITextField
            self.saveUser(self.textFieldName.text, email: self.textFieldEmail.text)
            self.tableView.reloadData()
    }

    saveAction.enabled = false

    let cancelAction = UIAlertAction(title: "Cancel",
        style: .Default) { (action: UIAlertAction!) -> Void in
    }

    alert.addTextFieldWithConfigurationHandler {
        (textFieldName: UITextField!) in
        textFieldName.placeholder = "Enter full name" …

有没有人找到一个清晰,简洁的示例或指南,介绍如何使用Lion中引入的基于视图的NSOutlineView实现源列表？我看过Apple的示例项目,但没有任何方向或解释感,我发现很难掌握它们究竟是如何工作的概念.

我知道如何使用优秀的PXSourceList作为后备,但是如果可能的话,我真的想开始使用基于视图的源列表.

如何在Linux Debian上安装PHP cURL？我尝试了以下代码并得到以下错误

apt-get update
apt-get install curl libcurl3 php5-curl

错误:

W: Failed to fetch http://zm.archive.ubuntu.com/ubuntu/dists/precise-updates/universe/binary-i386/Packages  Something wicked happened resolving 'zm.archive.ubuntu.com:http' (-5 - No address associated with hostname)

W: Failed to fetch http://zm.archive.ubuntu.com/ubuntu/dists/precise-updates/multiverse/binary-i386/Packages  Something wicked happened resolving 'zm.archive.ubuntu.com:http' (-5 - No address associated with hostname)

W: Failed to fetch http://zm.archive.ubuntu.com/ubuntu/dists/precise-updates/main/i18n/Translation-en_US  Something wicked happened resolving 'zm.archive.ubuntu.com:http' (-5 - No address associated with hostname)

W: Failed to fetch http://zm.archive.ubuntu.com/ubuntu/dists/precise-updates/main/i18n/Translation-en  Something wicked happened resolving 'zm.archive.ubuntu.com:http' (-5 - No address associated with hostname)

W: …

我试图运行此代码但我继​​续收到此错误:

致命错误:在展开Optional值时意外发现nil

我不明白这意味着什么或为什么我得到它.任何提示？

import UIKit

class ViewController: UIViewController {

var lastNumber: String = ""
@IBOutlet var answerField: UILabel
@IBOutlet var operaterLabel: UILabel

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func buttonTapped(theButton: UIButton) {
    if answerField.text == "0"
    {
        answerField.text = theButton.titleLabel.text
    }
    else
    {
        answerField.text = answerField.text + theButton.titleLabel.text
    }
}

@IBAction …

当我更改inputAccessoryViewiOS 8中的高度时,inputAccessoryView不会转到右侧原点,而是覆盖键盘.

以下是一些代码段:

在表视图控制器中

- (UIView *)inputAccessoryView {
    if (!_commentInputView) {
        _commentInputView = [[CommentInputView alloc] initWithFrame:CGRectMake(0, 0, [self width], 41)];
        [_commentInputView setPlaceholder:NSLocalizedString(@"Comment", nil) andButtonTitle:NSLocalizedString(@"Send", nil)];
        [_commentInputView setBackgroundColor:[UIColor whiteColor]];
        _commentInputView.hidden = YES;
        _commentInputView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleBottomMargin;
    }

    return _commentInputView;
}

在CommentInputView中

#when the textview change height
- (void)growingTextView:(HPGrowingTextView *)growingTextView willChangeHeight:(float)height {
    if (height > _textView_height) {
        [self setHeight:(CGRectGetHeight(self.frame) + height - _textView_height)];
        [self reloadInputViews];
    }
}

来自ios-helpers的 UIView类别

- (void)setHeight: (CGFloat)heigth {
    CGRect frame = self.frame;
    frame.size.height …

我正在尝试使用Hangfire在后台运行定期作业,轮询来自其他网站的数据,问题是如果上一个作业仍在运行,我不希望重复作业运行.

我已阅读文档,但似乎无法找到答案.有没有办法让一个每10分钟运行一次的重复工作,但如果之前的任务还没有完成则会跳过？

public void Configuration(IAppBuilder app)
{
    app.MapSignalR();

    // Hangfire
    GlobalConfiguration.Configuration
        .UseSqlServerStorage("DatabaseContext");

    app.UseHangfireDashboard();
    app.UseHangfireServer();

    RecurringJob.AddOrUpdate("site-parser", () => SiteParserService.RunAll(), Cron.Minutely, TimeZoneInfo.Utc);

    ConfigureAuth(app);
}

我有以下故事板与故事板参考segue:

问题是当我运行应用程序时,它不会显示图标或标题:

这些是项目设置:

我错过了什么？

我在构建项目时遇到错误.

错误:

Error:Execution failed for task ':app:processDebugResources'.
> com.android.ide.common.process.ProcessException: Failed to execute aapt
C:\Users\MR Maleki\Desktop\WhoIsBetter2\app\build\intermediates\res\merged\debug\values-v24\values-v24.xml
Error:(4) Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.Button.Colored'.
Error:(3) Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.Button.Borderless.Colored'.
Error:(3) Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.Button.Borderless.Colored'.
Error:(4) Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.Button.Colored'.

摇篮:

  compileSdkVersion GLOBAL_COMPILE_SDK as int …

我想调用一个函数,我希望该函数将程序中字符串或数组的内容更改为常量.

伪代码:

some_array = "hello"
print some_array   #prints "hello"
changeArray(some_array)
print some_array  #prints "bingo"

我知道我必须将指针传递给该函数.这是我写的,

void changeArray(char *arr){
    arr = "bingo";
}

int main(int argc, const char* argv[]){
    char *blah = "hello";
    printf("Array is %s\n",blah);
    changeArray(blah);
    printf("Array is %s\n",blah);
    return EXIT_SUCCESS;
}

我怎样才能做到这一点？