编写一个jsp页面，该页面提供一个表单，用户可以通过表单将三角形三边的长度提交给页面，用户提交表单后，jsp页面将计算三角形面积的任务交给一个bean去完成.-Write a jsp page, the page provides a form, users can form will be submitted to the length of the triangle triangular page, after the user submits the form, jsp page will calculate the triangle area to complete the task to a bean.