小编Hao*_*Xie的帖子

我的Apache 2.4在Windows Server 2008 R2上使用Xampp 1.8.2时遇到了一个非常奇怪的问题.

当我尝试在XAMPP中启动Apache服务器时,会显示一条错误消息:

[Apache]    Problem detected!
[Apache]    Port 443 in use by "Unable to open process" with PID 4!
[Apache]    Apache WILL NOT start without the configured ports free!
[Apache]    You need to uninstall/disable/reconfigure the blocking application
[Apache]    or reconfigure Apache and the Control Panel to listen on a different port

但是,PID 4的过程就是系统!我试图重新启动计算机,但它不起作用.

我几天前通过tar.gz文件安装了Apache 2.4,并将其卸载.所以,我不认为这种行为会导致问题.

这是使用commond netstat -a -n -o |的结果 findstr 443

C:\Users\Administrator>netstat -a -n -o | findstr 443
  TCP    0.0.0.0:443            0.0.0.0:0              LISTENING       4
  TCP …

升级到 Qt 5.15 时，我收到以下错误消息：

QML Connections: Implicitly defined onFoo properties in Connections are deprecated.
Use this syntax instead: function onFoo(<arguments>) { ... }

下面贴出对应的QML代码

Connections {
    target: AppProxy

    onLogsReady: function(logs) {
        textLogs.text = logs
    }
}

其中onLogsReady是AppProxy类中定义的信号：

class AppProxy : public QObject {
  Q_OBJECT
  Q_DISABLE_COPY(AppProxy)

 public:
  AppProxy(QObject* parent = 0);
  ~AppProxy();

 signals:
  void logsReady(QString logs);

// ...
};

我想知道如何抑制这个警告。

升级到Qt 6.0后，编译器告诉我

qzxing/src/QZXing.cpp:16: error: 'QtCore/QTextCodec' file not found
qzxing/src/QZXing.cpp:16:10: fatal error: 'QtCore/QTextCodec' file not found
#include <QtCore/QTextCodec>
         ^~~~~~~~~~~~~~~~~~~
qzxing/src/QZXing.cpp:16:10: note: did not find header 'QTextCodec' in framework 'QtCore' (loaded from '/Applications/Qt/6.0.0/clang_64/lib')

根据Qt的文档，可以通过添加QT += core5compat. 然而，编译器告诉我“QT 中的未知模块：core5compat”。

如何解决这个问题呢？

我有三个表，结构如下所示。

该表（称为contest_submissions）存储提交和竞赛的关系。

ContestID | SubmissionID

1           1000
1           1001
1           1002
1           1003

第二个表（称为submissions）存储提交的详细信息：

SubmissionID | ProblemID | User | Score | Time

1000           1000        A      100     1000
1001           1000        A      40      1250
1002           1001        A      50      1500
1003           1001        B      20      1750

另一个表（称为contest_contestants）包括：

ContestID | User

1           A
1           B

我写了以下SQL：

SELECT *, (
    SELECT SUM(score)
    FROM  contest_submissions cs
    NATURAL JOIN submissions
    WHERE user = cc.user
    AND SubmissionID = cs.SubmissionID
) AS TotalScore, …

我可以在shell中执行SQL:

LOAD DATA LOCAL INPATH '/tmp/sql.txt' INTO TABLE files;

这是sql.txt中的内容:

4e6c924a-1fa2-4326-86eb-975d1007f0a6 FileScoreConverterTest.java /home/xiehaozhe/Development/Kloud-Document-Analyzer/kda/src/test/java/com/kda/filescore/type/FileScoreConverterTest.java
ab6ee610-c980-4ff7-b472-8546766e0f89 FileWordCountConverterTest.java /home/xiehaozhe/Development/Kloud-Document-Analyzer/kda/src/test/java/com/kda/filescore/type/FileWordCountConverterTest.java

表的结构(命名文件)是

guid STRING
filename STRING
filepath STRING

如果我在Java中执行sql,我得到一个例外:

Exception in thread "main" java.sql.SQLException: Query returned non-zero code: 40000, cause: FAILED: ParseException line 1:54 mismatched input ';' expecting EOF near 'files'

这是代码:

Class.forName("org.apache.hadoop.hive.jdbc.HiveDriver");
String sql = "LOAD DATA LOCAL INPATH '" + sqlFilePath + "' INTO TABLE files;";
Connection connection = DriverManager.getConnection(databaseAddress, databaseUsername, databasePassword);
Statement statement = connection.createStatement();
statement.executeQuery(sql);

我该怎么办？

我想在C#中重载运算符'++',但是当我编写下面的代码时,VS 2012会给我一个错误消息.

    public LogItem operator ++()
    {
        ++ visitTimes;
    }

错误是重载的一元运算符++需要一个参数

我在这里是LogItem 类的定义:

     public class LogItem
     {
        /**
         * Constructor
         */
        public LogItem(string ip)
        {
            ipAddress = ip;
            visitTimes = 0;
        }

        /**
         * Operator Overload Function
         */
        public LogItem operator ++() 
        {
            ++ visitTimes;
        }

        public string ipAddress { get; private set; }
        public string location { get; set; }
        public int visitTimes { get; private set; }
     }

我该怎么做才能重载运算符'++'？