如果我单独请求则没有问题 但是如果我在请求数据的过程中另外一个用户进行请求。则报异常 后台打印数据 已经获取到 但是数据传输好像出问题了。是不是流的关闭和打开有问题？

异常：

ould not complete request

  java.lang.NullPointerException

at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:215)

at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:480)

at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:366)

at org.apache.coyote.http11.InternalOutputBuffer$OutputStreamOutputBuffer.doWrite(InternalOutputBuffer.java:240)

at org.apache.coyote.http11.filters.IdentityOutputFilter.doWrite(IdentityOutputFilter.java:93)

at org.apache.coyote.http11.AbstractOutputBuffer.doWrite(AbstractOutputBuffer.java:192)

at org.apache.coyote.Response.doWrite(Response.java:499)

at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:402)

at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:480)

at org.apache.catalina.connector.OutputBuffer.realWriteChars(OutputBuffer.java:485)