jfinal3.5,jfinal jetty-server 2018.11,然后引入了apache-jsp和apache-jstl，访问jsp页面时还是提示org.apache.jasper.JasperException: Unable to compile class for JSP，

Caused by: java.lang.NullPointerException

at org.apache.jasper.compiler.Validator$ValidateVisitor.<init>(Validator.java:516)

at org.apache.jasper.compiler.Validator.validateExDirectives(Validator.java:1854)

at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:221)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:374)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:351)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:335)

at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:595)

... 50 more

jetty文档中说需要在启动的时候设置一下，是不是目前的就用不了jsp了？