1. Customize the implementation class of Filter interface
1.1 Implement request and response interception of your own needs in doFilter
package com.test.filter;
import javax.servlet.*;
import java.io.IOException;
public class TestFilter implements Filter {
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
/*
* 登录用户验证
* */
if (servletRequest.getParameter("name").equals("sunlight")) {
filterChain.doFilter(servletRequest, servletResponse);
} else {
servletResponse.setCharacterEncoding("UTF-8");
servletResponse.setContentType("text/html;UTF-8");
servletResponse.getWriter().write("用户名称输入不正确");
}
System.out.println("过滤器拦截");
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void destroy() {
}
}
2. Configure filter in webapp/WEB-INF/web.xml
<filter>
<filter-name>testFilterConfig</filter-name>
<filter-class>com.test.filter.TestFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>testFilterConfig</filter-name>
<url-pattern>/testForm</url-pattern>
</filter-mapping>
filter-name filter name setting, customizable
filter-class effective filter class
url-pattern filter matching rule
note filter-mappinginnerfilter-nameNeed to match the filterfilter-namebe consistent
3.Achieve results