public String execute() throws Exception {
        if (this.getUserName().equals("angel") && this.getPassword().equals("123")) {
            this.setResult(true);
            return SUCCESS;
        } else if (this.getUserName().equals("aa")) {
            throw new SQLException("the UserException happened");
        } else {
            throw new Exception();
        }
}

<action name="exceptionAction" class="action.ExceptionAction">
            <exception-mapping result="exception" exception="SQLException" />
            <exception-mapping result="exception" exception="Exception" />
            <result name="exception">/exception.jsp</result>
</action>