奇怪问题，请高手指点，Illegal operation on empty result set.

[lxkj123]

特别说明：该问题对一部分数据提示错误，对一部分数据则正常，非常奇怪
null
java.sql.SQLException: Illegal operation on empty result set.
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926)
at com.mysql.jdbc.ResultSetImpl.checkRowPos(ResultSetImpl.java:815)
at com.mysql.jdbc.ResultSetImpl.getStringInternal(ResultSetImpl.java:552
8)
at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5448)
at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5488)
at net.sf.odinms.client.MaplePet.loadFromDb(MaplePet.java:46)
at net.sf.odinms.tools.MaplePacketCreator.addItemInfo(MaplePacketCreator
.java:1213)
at net.sf.odinms.tools.MaplePacketCreator.addItemInfo(MaplePacketCreator
.java:1144)
at net.sf.odinms.tools.MaplePacketCreator.getCharInfo(MaplePacketCreator
.java:866)
at net.sf.odinms.net.channel.handler.PlayerLoggedinHandler.handlePacket(
PlayerLoggedinHandler.java:94)
at net.sf.odinms.net.MapleServerHandler.messageReceived(MapleServerHandl
er.java:118)
at org.apache.mina.common.support.AbstractIoFilterChain$TailFilter.messa
geReceived(AbstractIoFilterChain.java:570)
at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageR
eceived(AbstractIoFilterChain.java:299)
at org.apache.mina.common.support.AbstractIoFilterChain.access$1100(Abst
ractIoFilterChain.java:53)
at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.mess
ageReceived(AbstractIoFilterChain.java:648)
at org.apache.mina.filter.codec.support.SimpleProtocolDecoderOutput.flus
h(SimpleProtocolDecoderOutput.java:58)
at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(Prot
ocolCodecFilter.java:180)
at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageR
eceived(AbstractIoFilterChain.java:299)
at org.apache.mina.common.support.AbstractIoFilterChain.access$1100(Abst
ractIoFilterChain.java:53)
at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.mess
ageReceived(AbstractIoFilterChain.java:648)
at org.apache.mina.filter.executor.ExecutorFilter.processEvent(ExecutorF
ilter.java:220)
at org.apache.mina.filter.executor.ExecutorFilter$ProcessEventsRunnable.
run(ExecutorFilter.java:264)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source
)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnabl
e.java:51)
at java.lang.Thread.run(Unknown Source)

[hp5212000]

"特别说明：该问题对一部分数据提示错误，对一部分数据则正常，非常奇怪 "
lz所说这个是什么意思？

[hp5212000]

Illegal operation on empty result set

你的数据集返回的是null值
1） 检查你的sql语句 是否正确
2） 确实无数据返回 要加异常处理

[zhuzhusany]

看Exception就知道，是对空数据集的操作是非法的

[lxkj123]

源程序对应：
public static MaplePet loadFromDb(int itemid, byte position, int petid) {
try {
MaplePet ret = new MaplePet(itemid, position, petid);
Connection con = DatabaseConnection.getConnection(); // Get a connection to the database
PreparedStatement ps = con.prepareStatement("SELECT * FROM pets WHERE petid = ?"); // Get pet details..
ps.setInt(1, petid);
ResultSet rs = ps.executeQuery();
if(rs.next());
{
ret.setName(rs.getString("name"));
ret.setCloseness(rs.getInt("closeness"));
ret.setLevel(rs.getInt("level"));
ret.setFullness(rs.getInt("fullness"));
}
rs.close();
ps.close();
return ret;
} catch (SQLException ex) {
Logger.getLogger(MaplePet.class.getName()).log(Level.SEVERE, null, ex);
return null;
}
}

[gjgj3368]

//有可能rs为空
if(rs.next());

[bunrise]

if(rs.next()); //这里这么有个分号？


if(rs != null && rs.next()){}

[lxkj123]

[Quote=引用 5 楼 lxd520123 的回复:]
if(rs.next()); //这里这么有个分号？


if(rs != null && rs.next()){}

[/Quote]

按如上修改后，还是提示一样的错误，真是奇怪了，大家看看还有什么可能？

[bunrise]

SELECT * FROM pets WHERE petid = id
去数据库先查一查数据在说，你数据库没数据吧

[focusforce]

if(rs.next())
{
ret.setName(rs.getString("name"));
ret.setCloseness(rs.getInt("closeness"));
ret.setLevel(rs.getInt("level"));
ret.setFullness(rs.getInt("fullness"));
}
重新运行试试，保证执行的是重新编译过的class。

[lxkj123]

[Quote=引用 8 楼 focusforce 的回复:]
if(rs.next())
            {
            ret.setName(rs.getString("name"));
            ret.setCloseness(rs.getInt("closeness"));
            ret.setLevel(rs.getInt("level"));
            ret.setFullness(rs.getInt("fullness"));
            }
重新运行试试，保证执行的是重新编译过的class。
[/Quote]

经反复测试，问题依旧，大家再看看还有什么问题？

[focusforce]

rs.close(); 放到finally语句试试

[bunrise]

if(rs.next());
{
ret.setName(rs.getString("name"));
ret.setCloseness(rs.getInt("closeness"));
ret.setLevel(rs.getInt("level"));
ret.setFullness(rs.getInt("fullness"));
} else{
return null;
}

return ret;
} catch (SQLException ex) {
Logger.getLogger(MaplePet.class.getName()).log(Level.SEVERE, null, ex);
return null;
}finnal{
rs.close();
ps.close();
}