java.nio.BufferOverflowException

完整的错误信息：

十一月 30, 2017 10:54:52 上午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [SpringMVC] in context with path [/smarthome] threw exception [Request processing failed; nested exception is java.nio.BufferOverflowException] with root cause
java.nio.BufferOverflowException
	at java.nio.Buffer.nextPutIndex(Buffer.java:521)
	at java.nio.HeapByteBuffer.put(HeapByteBuffer.java:169)
	at com.wanyu.smarthome.gateway.GatewayInstance.sendCommand(GatewayInstance.java:141)
	at com.wanyu.smarthome.mobile.EquipmentMobile.DeferredAdd(EquipmentMobile.java:520)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:690)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at com.wanyu.frame.base.AuthFilter.doFilter(AuthFilter.java:97)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:509)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1104)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1524)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1480)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

这是在操作 java.nio.ByteBuffer 时出现的错误。 错误原因： 写入的长度超出了允许的长度：

例如下面的代码：

ByteBuffer params = ByteBuffer.allocate(2);//   这里只分配了2个字节，下面的params.put(tmp);却put了3个字节的数据。所以导致 java.nio.BufferOverflowException 异常
        params.order(ByteOrder.LITTLE_ENDIAN); 
        byte[] tmp = new byte[3];
        tmp[0] = (byte) data1;
        tmp[1] = (byte) data2;
        tmp[2] = (byte) data3;
	params.put(tmp);

但实际使用中 ByteBuffer 的使用没有这么简单。

如何解决这个问题呢？

添加写入长度与 ByteBuffer 中可写入的长度的判断，例如：

while (writeBuffer.remaining() > 0) {
			writeBuffer.put((byte)0);
		}

注意：你每次只写入一个字节，那就判断大于0就好了，如果不是一个记得修改条件哦！

总结

当 ByteBuffer.remaining()  小于要读取或写入的长度时，再执行读取或写入操作都会产生异常；

读取则产生 java.nio.BufferUnderflowException 异常，

写入则产生 java.nio.BufferOverflowException 异常。

当 ByteBuffer.remaining()  等于 0 时，不能再执行读取或写入操作，需要执行：clear() 操作，否则将产生异常。

你可能也会遇到这个异常： 

java.nio.BufferUnderflowException