javax.servlet.ServletException: Cannot expose request attribute解决方案

javax.servlet.ServletException: Cannot expose request attribute
javax.servlet.ServletException: Cannot expose request attribute 'testing'
because of an existing model object of the same name

这种问题会是什么原因引起？

[解决办法]
把代码贴出来，你是不是从request中获取这个字段啊？