Servlet过滤器

最新推荐文章于 2024-09-03 11:33:25 发布

lpZhouYi

最新推荐文章于 2024-09-03 11:33:25 发布

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分类专栏： Java web 文章标签： servlet

本文链接：https://blog.youkuaiyun.com/lpZhouYi/article/details/80649476

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Servlet过滤器

代码：

提交表单

<%--
  Created by IntelliJ IDEA.
  User: liupe
  Date: 2018-06-11
  Time: 10:46
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>上传数据通过滤器</title>
</head>
<body>

<form action="/lp001/Servlet005" method="post">
    <p>上传内容:</p>
    <input type="text" name="name">
    <br>
    <input type="submit" value="提交">

</form>
</body>
</html>

过滤器

package lp001;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@WebFilter(filterName = "Filter001")
public class Filter001 implements Filter {
    public void destroy() {
        System.out.println("销毁过滤器!");
    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
            throws ServletException, IOException {
        //将Servlet对象，转化成HttpServlet对象
        HttpServletResponse httpServletResponse = (HttpServletResponse)resp;
        HttpServletRequest httpServletRequest = (HttpServletRequest)req;
        String name = httpServletRequest.getParameter("name");
        if ("liupeng".equals(name)) {
            System.out.println("遇到刘鹏！");
            chain.doFilter(httpServletRequest, httpServletResponse );
        } else {
            chain.doFilter(httpServletRequest, httpServletResponse );
        }
        // 放行 (去到Servlet)
        // 如果有下一个过滤器，进入下一个过滤器，否则就执行访问servlet
                // 把请求传回过滤链

    }

    public void init(FilterConfig config) throws ServletException {
        String name = config.getInitParameter("name");
        System.out.println("name = " + name + ".");
    }

}

Servlet

package lp001;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet(name = "Servlet005")
public class Servlet005 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        //response.setCharacterEncoding("UTF-8");
        //request.setCharacterEncoding("UTF-8");

        PrintWriter out = response.getWriter();
        String name = request.getParameter("name");
        name = new String(name.getBytes("ISO8859-1"),"UTF-8");
        System.out.println("name:" + name);

        //String newName = request.

        out.println("<h1>" + name + "</h1>");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request,response);
    }
}