[Exception] java.lang.IllegalArgumentException: Prefix string too short

1. 情景： File.createTempFile(“temp”,suffix);
2. 异常：java.lang.IllegalArgumentException: Prefix string too short
3. 原因：这个方法要求前缀不得少于3个字符
4. 解决方案：增加前缀长度（第一个参数），或换其它方法创建文件
5. 异常详细信息：
   java.lang.IllegalArgumentException: Prefix string too short
   at java.io.File.createTempFile(File.java:2001) ~[na:1.8.0_102]
   at java.io.File.createTempFile(File.java:2070) ~[na:1.8.0_102]
   at cn.jintongsoft.dev.QAExtractor.getQAFromDocument(QAExtractor.java:20) ~[na:na]
   at com.alibaba.dubbo.common.bytecode.Wrapper1.invokeMethod(Wrapper1.java) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.proxy.javassist.JavassistProxyFactory 1.doInvoke(JavassistProxyFactory.java:46) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.proxy.AbstractProxyInvoker.invoke(AbstractProxyInvoker.java:72) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:53) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.filter.ExceptionFilter.invoke(ExceptionFilter.java:64) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1. d o I n v o k e ( J a v a s s i s t P r o x y F a c t o r y . j a v a : 46 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o x y . A b s t r a c t P r o x y I n v o k e r . i n v o k e ( A b s t r a c t P r o x y I n v o k e r . j a v a : 72 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o t o c o l . I n v o k e r W r a p p e r . i n v o k e ( I n v o k e r W r a p p e r . j a v a : 53 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . f i l t e r . E x c e p t i o n F i l t e r . i n v o k e ( E x c e p t i o n F i l t e r . j a v a : 64 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o t o c o l . P r o t o c o l F i l t e r W r a p p e r 1.invoke(ProtocolFilterWrapper.java:91) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:75) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1.invoke(ProtocolFilterWrapper.java:91) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.filter.TimeoutFilter.invoke(TimeoutFilter.java:42) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1. i n v o k e ( P r o t o c o l F i l t e r W r a p p e r . j a v a : 91 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . f i l t e r . T i m e o u t F i l t e r . i n v o k e ( T i m e o u t F i l t e r . j a v a : 42 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o t o c o l . P r o t o c o l F i l t e r W r a p p e r 1.invoke(ProtocolFilterWrapper.java:91) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.protocol.dubbo.filter.TraceFilter.invoke(TraceFilter.java:78) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1.invoke(ProtocolFilterWrapper.java:91) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.filter.ContextFilter.invoke(ContextFilter.java:60) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1. i n v o k e ( P r o t o c o l F i l t e r W r a p p e r . j a v a : 91 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . f i l t e r . C o n t e x t F i l t e r . i n v o k e ( C o n t e x t F i l t e r . j a v a : 60 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o t o c o l . P r o t o c o l F i l t e r W r a p p e r 1.invoke(ProtocolFilterWrapper.java:91) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.filter.GenericFilter.invoke(GenericFilter.java:112) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1.invoke(ProtocolFilterWrapper.java:91) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.filter.ClassLoaderFilter.invoke(ClassLoaderFilter.java:38) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1. i n v o k e ( P r o t o c o l F i l t e r W r a p p e r . j a v a : 91 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . f i l t e r . C l a s s L o a d e r F i l t e r . i n v o k e ( C l a s s L o a d e r F i l t e r . j a v a : 38 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o t o c o l . P r o t o c o l F i l t e r W r a p p e r 1.invoke(ProtocolFilterWrapper.java:91) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.filter.EchoFilter.invoke(EchoFilter.java:38) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper 1.invoke(ProtocolFilterWrapper.java:91) [dubbo−2.8.4.jar:2.8.4]atcom.alibaba.dubbo.rpc.protocol.dubbo.DubboProtocol 1. i n v o k e ( P r o t o c o l F i l t e r W r a p p e r . j a v a : 91 )   [ d u b b o − 2.8.4. j a r : 2.8.4 ] a t c o m . a l i b a b a . d u b b o . r p c . p r o t o c o l . d u b b o . D u b b o P r o t o c o l 1.reply(DubboProtocol.java:108) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.handleRequest(HeaderExchangeHandler.java:84) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:170) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:52) ~[dubbo-2.8.4.jar:2.8.4]
   at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:82) ~[dubbo-2.8.4.jar:2.8.4]
   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_102]
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_102]
   at java.lang.Thread.run(Thread.java:745) ~[na:1.8.0_102]