Java开发网 - 求助：关于jboss查找实体bean的问题

Topic: 求助：关于jboss查找实体bean的问题

1.求助：关于jboss查找实体bean的问题

Posted by: tozx96
Posted on: 2003-07-13 18:57

我写了两个cmp1.1，名称分别是TestPerson和EstItem，然后我写了一个sessionbean，名成为EnterpriseBean1，我的目的就是在EnterpriseBean1查找相应的实体bean，代码如下：
Collection estItemCol = estItemHome.findSystemItem();
System.out.println(estItemCol.size() );
Iterator iteEstItem = estItemCol.iterator() ;
while(iteEstItem.hasNext() ){
Object obj = iteEstItem.next() ;
EstItem estItem = (EstItem)PortableRemoteObject.narrow(obj,EstItem.class);
System.out.println(estItem.getItemName() );
}

Collection testPersonCol = testPersonHome.findByIdAndName("200307000001","a");
System.out.println(testPersonCol.size() );
Iterator ite = testPersonCol.iterator() ;
while(ite.hasNext() ){
Object obj = ite.next() ;
TestPerson testPerson = (TestPerson)PortableRemoteObject.narrow(obj,TestPerson.class);
System.out.println(testPerson.getPersonName());
}
这段代码的目的就是输出两个实体bean的fander方法的结果，但是执行到estItem.getItemName() 出下了如下异常：
18:34:49,853 ERROR [JDBCCommand] Exception caught executing SQL
java.sql.SQLException: [Microsoft][SQLServer JDBC Driver]ResultSet can not re-re
ad row data for column 1.(后面还有很长的异常信息，但可能没用，所以就写出来)
更奇怪的是testPerson.getPersonName()又不会出现这个异常。
请各位高手指点。非常谢谢。

2.Re:求助：关于jboss查找实体bean的问题 [Re: tozx96]	Copy to clipboard
Posted by: why Posted on: 2003-07-13 19:29 This "ResultSet can not re-read" problem is not unpopular. If your query returns column of type 'image' or 'text' or 'ntext', then it's a restriction -- you have to call the getXXX() methods in order. Otherwise, it's most likely a bug of SQL Server JDBC driver. Try another JDBC driver.

3.Re:求助：关于jboss查找实体bean的问题 [Re: tozx96]	Copy to clipboard
Posted by: tozx96 Posted on: 2003-07-13 19:53 非常谢谢。不过还是不理解getXXX()怎么用？能否说详细些？再次谢谢。

4.Re:求助：关于jboss查找实体bean的问题 [Re: tozx96]	Copy to clipboard
Posted by: tozx96 Posted on: 2003-07-13 20:22 我是不是得把cmp改写成bmp，然后再在bmp的ejbLoad()方法中用getXXX()来处理？

5.Re:求助：关于jboss查找实体bean的问题 [Re: tozx96]	Copy to clipboard
Posted by: why Posted on: 2003-07-13 20:37 I didn't have CMP in my mind when I wrote getXXX() if the sql statement is SELECT a, b, c, d FROM t then the columns a, b, c, d must be retrieved in order, i.e. ab, acd, cd, but not da etc. You can 改写成bmp if you wish, but I would just use another JDBC driver.

6.Re:求助：关于jboss查找实体bean的问题 [Re: tozx96]	Copy to clipboard
Posted by: tozx96 Posted on: 2003-07-13 21:48 非常谢谢。