【HTTP】content-length: 实体的长度

报文是箱子，实体是货物

HTTP 权威指南中提到
可以把HTTP报文看成是网络货运系统的箱子，HTTP实体就是货物 like this

报文实体

实体首部指出这是一个纯文本文档(Content-Type:text/plain)，它只有18个字节长(Content-Length:18)，一个空白行(CRLF)把首部字段同主体的开始部分分隔开来

内容编码

HTTP运行对实体主体的内容进行编码，
比如可以使之更安全或者进行压缩以节省空间
如果主体进行了内容编码，
Content-Length首部说明的就是编码后的主体的字节长度，
而不是未编码的原始主体的长度

长度异常

过短会被截取
过长有可能超时也有可能报错

过短

短了

报错信息

{
    "timestamp": "2021-08-08T04:48:17.110+00:00",
    "status": 400,
    "error": "Bad Request",
    "trace": "org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Unexpected end-of-input: expected close marker for Object (start marker at [Source: (PushbackInputStream); line: 1, column: 1]); nested exception is com.fasterxml.jackson.core.io.JsonEOFException: Unexpected end-of-input: expected close marker for Object (start marker at [Source: (PushbackInputStream); line: 1, column: 1])\n at [Source: (PushbackInputStream); line: 1, column: 21]\r\n\tat org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:389)\r\n\tat org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:342)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:186)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:158)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:131)\r\n\tat org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:170)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)\r\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1060)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:962)\r\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)\r\n\tat org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:626)\r\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:733)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)\r\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)\r\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)\r\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)\r\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)\r\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\r\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)\r\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)\r\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)\r\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)\r\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)\r\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707)\r\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\r\n\tat java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)\r\n\tat java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)\r\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\r\n\tat java.lang.Thread.run(Thread.java:748)\r\nCaused by: com.fasterxml.jackson.core.io.JsonEOFException: Unexpected end-of-input: expected close marker for Object (start marker at [Source: (PushbackInputStream); line: 1, column: 1])\n at [Source: (PushbackInputStream); line: 1, column: 21]\r\n\tat com.fasterxml.jackson.core.base.ParserMinimalBase._reportInvalidEOF(ParserMinimalBase.java:659)\r\n\tat com.fasterxml.jackson.core.base.ParserBase._handleEOF(ParserBase.java:486)\r\n\tat com.fasterxml.jackson.core.base.ParserBase._eofAsNextChar(ParserBase.java:498)\r\n\tat com.fasterxml.jackson.core.json.UTF8StreamJsonParser._skipWSOrEnd(UTF8StreamJsonParser.java:2989)\r\n\tat com.fasterxml.jackson.core.json.UTF8StreamJsonParser.nextFieldName(UTF8StreamJsonParser.java:997)\r\n\tat com.fasterxml.jackson.databind.deser.std.MapDeserializer._readAndBindStringKeyMap(MapDeserializer.java:525)\r\n\tat com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:377)\r\n\tat com.fasterxml.jackson.databind.deser.std.MapDeserializer.deserialize(MapDeserializer.java:29)\r\n\tat com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4526)\r\n\tat com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3521)\r\n\tat org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:378)\r\n\t... 58 more\r\n",
    "message": "JSON parse error: Unexpected end-of-input: expected close marker for Object (start marker at [Source: (PushbackInputStream); line: 1, column: 1]); nested exception is com.fasterxml.jackson.core.io.JsonEOFException: Unexpected end-of-input: expected close marker for Object (start marker at [Source: (PushbackInputStream); line: 1, column: 1])\n at [Source: (PushbackInputStream); line: 1, column: 21]",
    "path": "/test/param/get/complex"
}

因为过短会被截断 json会解析失败

过长

爱的魔力转圈圈 超长报错返回HTML

过长会报错或者超时