小编Ana*_*mar的帖子

我想在浏览器关闭或标签关闭后终止会话.我需要在会话到期后使用Session Listener.But进行一次数据库连接,为此我需要等到会话销毁.

这是会话销毁时执行的代码.

public void sessionDestroyed(HttpSessionEvent event) {
        synchronized (this) {
            //System.out.println("deletion");
            ServletContext application = event.getSession().getServletContext();
            sessionCount = (Integer) application.getAttribute("SESSION_COUNT");
            application.setAttribute("SESSION_COUNT", sessionCount=sessionCount - 1);
            //application.setAttribute("SESSION_COUNT", --sessionCount);


            try
            {
                Class.forName("com.mysql.jdbc.Driver");
            }
            catch (ClassNotFoundException e) {
                System.out.println("" + e);
            }

            Connection connection = null;
            try {
                connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/raptor1_5", "root", "");
                Statement st = connection.createStatement();

                st.executeUpdate("update adminlogin set Password='admin' where Username='admin'");  

            }   catch (SQLException e) {
                e.printStackTrace();
            }

        }
        System.out.println("Session Destroyed: " + event.getSession().getId());
        System.out.println("Total Sessions after delete: " + sessionCount);
    } …

我正在通过Java尝试与我的Cassandra实例的简单连接.我为cqlsh创建了一个'demo'键空间,并在java程序中创建了一个表.代码如下:

使用的罐子:

• slf4j.api-1.6.1

• 卡桑德拉-ALL-2.1.2

  public class CassandraConnection {
  
      public static void main(String[] args){
  
          String ipAddress="127.0.0.1";
          String keySpace="demo";
  
          Cluster cluster;
  
          Session session;
  
          cluster=Cluster.builder().addContactPoint(ipAddress).build();
  
          session=cluster.connect(keySpace);
  
          System.out.println("====================Before insert");
  
          String cqlInsertStmt="insert into users (lastname,age,city,email,firstname) values"
          +"('Gopalan',32,'Paramakkudi','murugan@gmail.com','Murugan') ";
  
          session.execute(cqlInsertStmt);
  
          String cqlSelectStmt="select * from users";
          ResultSet resultSet=session.execute(cqlSelectStmt);
  
          System.out.println("=================After insert");
  
          for(Row row: resultSet){
  
              System.out.format("%s %s %d %s %s \n", row.getString("firstname"),row.getString("lastname"),row.getInt("age"),row.getString("city"),row.getString("email"));
          }
  
          System.out.println("=================After update");
  
      }
  }
  

  Run Code Online (Sandbox Code Playgroud)

我收到以下错误:

Failed to instantiate SLF4J LoggerFactory
Reported exception:
java.lang.NoClassDefFoundError: ch/qos/logback/core/joran/spi/JoranException
    at org.slf4j.LoggerFactory.bind(LoggerFactory.java:150)
    at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:124)
    at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:412)
    at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:357)
    at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:383)
    at com.datastax.driver.core.Cluster.<clinit>(Cluster.java:60) …