关于jsp web项目中的javax.servlet.ServletException: java.lang.NoClassDefFoundError: javax/el/ELResolver错误

错误：

javax.servlet.ServletException: java.lang.NoClassDefFoundError: javax/el/ELResolver
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:343)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.NoClassDefFoundError: javax/el/ELResolver
java.lang.ClassLoader.defineClass1(Native Method)
java.lang.ClassLoader.defineClass(Unknown Source)
java.security.SecureClassLoader.defineClass(Unknown Source)
java.net.URLClassLoader.defineClass(Unknown Source)
java.net.URLClassLoader.access$100(Unknown Source)
java.net.URLClassLoader$1.run(Unknown Source)
java.net.URLClassLoader$1.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.net.URLClassLoader.findClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
org.apache.jasper.runtime.JspFactoryImpl.getJspApplicationContext(JspFactoryImpl.java:220)
org.apache.jsp.result_jsp._jspInit(result_jsp.java:33)
org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)
org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:180)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause

java.lang.ClassNotFoundException: javax.el.ELResolver
java.net.URLClassLoader$1.run(Unknown Source)
java.net.URLClassLoader$1.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.net.URLClassLoader.findClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.defineClass1(Native Method)
java.lang.ClassLoader.defineClass(Unknown Source)
java.security.SecureClassLoader.defineClass(Unknown Source)
java.net.URLClassLoader.defineClass(Unknown Source)
java.net.URLClassLoader.access$100(Unknown Source)
java.net.URLClassLoader$1.run(Unknown Source)
java.net.URLClassLoader$1.run(Unknown Source)
java.security.AccessController.doPrivileged(Native Method)
java.net.URLClassLoader.findClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
java.lang.ClassLoader.loadClass(Unknown Source)
org.apache.jasper
4000
.runtime.JspFactoryImpl.getJspApplicationContext(JspFactoryImpl.java:220)
org.apache.jsp.result_jsp._jspInit(result_jsp.java:33)
org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)
org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:180)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

这个错误出现的原因是你把jsp-api.jar和servlet-api.jar这两个jar都加入到了jdk的classpath之中了，解决办法就是把jsp-api.jar删除，删除servlet-api.jar不会起作用，否则会出现jsp文件不能访问的错误,解决问题so easy。