formcheckfilter.java

jsp 应用开发技术光盘 是《jsp应用开发技术》这本书的源代码

package ch17;

import java.io.IOException;
import javax.servlet.*;

/**
 * 校验表单数据过滤器
 */
public class FormCheckFilter implements Filter {

	protected FilterConfig config;

	public void init(FilterConfig filterConfig) throws ServletException {
		this.config = filterConfig;
	}

	public void doFilter(
		ServletRequest request,
		ServletResponse response,
		FilterChain chain)
		throws IOException, ServletException {
		String name = request.getParameter("name");
		String strAge = request.getParameter("age");
		int age;

		RequestDispatcher dispatcher =
			request.getRequestDispatcher("formCheckFail.jsp");

		if (name == null || strAge == null) {
			// 重定向到formCheckFail.jsp页面
			dispatcher.forward(request, response);
			return;
		}
		try {
			age = Integer.parseInt(strAge);
		} catch (NumberFormatException e) {
			// 重定向到formCheckFail.jsp页面
			dispatcher.forward(request, response);
			return;
		}
		chain.doFilter(request, response);
	}

	public void destroy() {

	}

}