SQLNonTransientConnectionException：没有当前连接，在我的应用程序中与Derby数据库交互 [英] SQLNonTransientConnectionException: No current connection, in my application while interacting with Derby database

问题描述

我在我的应用程序中实现了德比数据库来保存我的数据，我在Derby数据库中检索结果集形式 select 时获取此异常。
要建立连接，我使用连接字符串作为：

我使用这种方法建立连接：

我在类中声明此方法Connection.java ：

  public synchronized Connection createConnection {
 
 Connection rescon = null; 
 
 try {
 if（this.dbuser == null）{
 rescon = DriverManager.getConnection（this.URI +; create = true）; 
} else {
 rescon = DriverManager.getConnection（this.URI +; create = true，
 this.dbuser，this.dbpass）; 
} 
 //在连接池创建的新连接
} catch（SQLException e）{
 final String stackNum = Utility.exceptionHandler（e）; 
 throw new Exception（Exception get during Connection  - + e.getMessage（））; 
} 
 return rescon; 
} 
  

我使用这个方法作为创建连接，

  private Connection objConnection = null; 
 objConnectionpool = new Connection（jdbc：derby：+ Folder.getAbsolutePath（）+/ myapplication+ sFileName，null，null，org.apache.derby.jdbc.EmbeddedDriver）; 
 objConnection = objConnectionpool.createNewConnection（）; 
  

我在执行查询时遇到异常：

  sQuery =select value，reason from+ TableNm +where fileName ='+ FileName +'AND type ='+ Type +'AND status ='remaining' ; 
  

在处理和交互Derby数据库期间，我们可能会更新从数据库获取数据： p>

在插入数据库之前，我执行setAutoCommit为false

  objConnection.setAutoCommit （假）; 
  

：

  ps = objConnection.prepareStatement（sQuery）; 
 rs = ps.executeQuery（）; 
 objConnection.commit（）; 
 objConnection.setAutoCommit（true）; 
  

我得到异常

  java.sql.SQLNonTransientConnectionException：没有当前连接。 
 at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException（未知源）
 at org.apache.derby.impl.jdbc.Util.newEmbedSQLException（未知源）
在org .apache.derby.impl.jdbc.Util.newEmbedSQLException（未知源）
 at org.apache.derby.impl.jdbc.Util.noCurrentConnection（未知源）
 at org.apache.derby.impl .jdbc.EmbedConnection.checkIfClosed（未知源）
 at org.apache.derby.impl.jdbc.EmbedConnection.setupContextStack（未知源）
 at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement （未知源）
 at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement（未知源）
 at com.myapplication.c.aw.a（未知源）
 at com .myapplication.c.aw.a（未知来源）
 at com.myapplication.main.avd.run（未知来源）
原因：java.sql.SQLException：没有当前连接。 
 at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException（未知源）
 at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA（未知源）
 .. 。另外11个
  

解决方案

>

我有同样的问题，在这个示例应用程序中找到我的答案： http://db.apache.org/derby/docs/10.4/devguide/rdevcsecure26537.html

  //强制垃圾收集以卸载EmbeddedDriver 
 //因此可以重新启动Derby 
 System.gc（）; 
  

现在可以正常工作。

I implemented derby data base in my application to save my data,and I am getting this exception in retrieval of result set form select query in Derby database. To establish the connection I use connection string as:

I establish connection using this method:

I declare this method in class Connection.java:

 public synchronized Connection createConnection() throws Exception {

        Connection rescon = null;

        try {
            if (this.dbuser == null) {
                rescon = DriverManager.getConnection(this.URI + ";create=true");
                } else {
                rescon = DriverManager.getConnection(this.URI + ";create=true",
                        this.dbuser, this.dbpass);
            }
            // new connection in connection pool created
        } catch (SQLException e) {
            final String stackNum = Utility.exceptionHandler(e);
            throw new Exception("Exception get during Connection - " + e.getMessage());
        }
        return rescon;
    }

I used this method as and create connection, create connection during intraction using string:

private Connection objConnection = null;
objConnectionpool = new Connection("jdbc:derby:" + Folder.getAbsolutePath() +        "/myapplication" + sFileName, null, null, "org.apache.derby.jdbc.EmbeddedDriver");
objConnection =  objConnectionpool.createNewConnection();

I am getting exception in execution of query:

sQuery = "select value,reason from " + TableNm + " where fileName ='" + FileName + "' AND type='"+Type+"' AND status ='remaining'"; 

during processing and interaction with Derby database we might update as well get the data from the database:

I perform setAutoCommit as false before inserting in the database

objConnection.setAutoCommit(false);

after insertion:

ps = objConnection.prepareStatement(sQuery);
rs = ps.executeQuery();
objConnection.commit();
objConnection.setAutoCommit(true);

I am getting Exception as

java.sql.SQLNonTransientConnectionException: No current connection.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.noCurrentConnection(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.checkIfClosed(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.setupContextStack(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown Source)
    at com.myapplication.c.aw.a(Unknown Source)
    at com.myapplication.c.aw.a(Unknown Source)
    at com.myapplication.main.avd.run(Unknown Source)
Caused by: java.sql.SQLException: No current connection.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
    ... 11 more

解决方案

Found this via Google.

I had the same problem and found my answer in this sample application: http://db.apache.org/derby/docs/10.4/devguide/rdevcsecure26537.html

// force garbage collection to unload the EmbeddedDriver
// so Derby can be restarted
System.gc();

Works perfectly now.

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