Solve the problem of encryption and decryption illegal key size

When accessing WeChat, the first step is to authenticate. If you directly call the official demo, it will report an Illegal key size error.
Solution :
Check your JDK version, mine is 1.8
and download it here: http://www.oracle. com/technetwork/java/javase/downloads/jce8-download-2133166.html
this is for 1.7: http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html
will The decompressed files cover the local_policy.jar and US_export_policy.jar in the /jdk1.8.0_151/jre/lib/security/policy/limited/ folder,
restart tomcat, and then get it done!