tomcat6升级到7时400问题：
在文件catalina.properties后加入tomcat.util.http.parser.HttpParser.requestTargetAllow=|。
tomcat7，url带有汉字时出错：
之前使用tomcat6，url带有汉字时没有问题，但是升级到7时，就出现一下错误，前台是winform，后台java。
Error parsing HTTP request header
Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level.
java.lang.IllegalArgumentException: Invalid character found in the request target. The valid characters are defined in RFC 7230 and RFC 3986
at org.apache.coyote.http11.InternalInputBuffer.parseRequestLine(InternalInputBuffer.java:194)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1052)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:662)
解决方案：把url内的中文转码成，GB2312，后台接收时，也用同样格式解码。
前台：
string url = p_sUrl;
for (int i = 0; i < url .Length; i++)
{
if ((int)url [i] > 127)
{
String str = url [i].ToString();
p_sUrl = p_sUrl.Replace(str, System.Web.HttpUtility.UrlEncode(str, Encoding.GetEncoding("GB2312")));
}
}
try
{
http.open("POST", p_sUrl, false, "", "");
http.send(p_bStr);
}
后台：
request.setCharacterEncoding("GB2312");