web.xml下面加這個,注意config.DemoConfig要和自己包名及類名對應
在此我的是config包下demoConfig.java

  <filter>
    <filter-name>jfinal</filter-name>
    <filter-class>com.jfinal.core.JFinalFilter</filter-class>
    <init-param>
       <param-name>configClass</param-name>
       <param-value>config.DemoConfig</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>jfinal</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
 

啟動類寫這個

	public static void main(String[] args) {
	    JFinal.start("src/main/webapp", 80, "/", 5);
	}

DemoConfig中其他的都不用配就這個加入，前提是要有HelloController類

	public void configRoute(Routes me) {
		me.add("/hello", HelloController.class);
		
	}

HelloController這麼寫

public class HelloController extends Controller{
	public void index() {
		renderText("Hello World");
	}

}