[FIXED] Invalid character found in the request target Tomcat 9

Issue

In the migration of a project that works correctly under Tomcat 7 to Tomcat 9 I am receiving the error Invalid character found in the request target when passing words with accents in the request.

The server.xml file was modified by introducing in the connector URIEncoding="UTF-8" and the clause relaxedQueryChars= áÁéÉíÍóÓúÚ was also introduced, but I still receive the same error. I can't touch the actual code of the project.

log traces show this: java.lang.IllegalArgumentException: Invalid character found in the request target [/sahab/lupaDem.do?filtro=LupaDem&param1=1&param2=29527&param3=OBSERVACI0xd3N%20ANTIRR0xc1BICA

Solution

HTTP does not allow to specify an encoding for the requested path. Thus in the past servers used OS settings which were actually confusing especially for applications used world-wide.

Therefore the standard established to always encode requests as UTF-8, and even then there is the URLEncoding which would prevent UTF-8 problems by %-escaping any special characters.

In a nutshell, ensure your requests are properly encoded. Previous versions of Tomcat may not have errored on this. The requests are coming from the client, not the server itself.

Answered By - Hiran Chaudhuri
Answer Checked By - Senaida (JavaFixing Volunteer)