在web.xml中扑捉异常

 <error-page>

        <error-code>400</error-code>

        <location>/error.jsp</location>

    </error-page>

<!-- 404 页面不存在错误 -->

    <error-page>

        <error-code>404</error-code>

        <location>/error.jsp</location>

    </error-page>

   <!-- 500 服务器内部错误 -->

    <error-page>

        <error-code>500</error-code>

        <location>/error.jsp</location>

    </error-page>

    <!-- java.lang.Exception异常错误,依据这个标记可定义多个类似错误提示 -->

    <error-page>

        <exception-type>java.lang.Exception</exception-type>

        <location>/error.jsp</location>

    </error-page>

    <!-- java.lang.NullPointerException异常错误,依据这个标记可定义多个类似错误提示 -->

    <error-page>

        <exception-type>java.lang.NullPointerException</exception-type>

        <location>/error.jsp</location>

    </error-page>

    <error-page>

        <exception-type>javax.servlet.ServletException</exception-type>

        <location>/error.jsp</location>

    </error-page>