过滤器的使用

使用过滤器之前:

使用过滤器之后:

过滤器的使用_第1张图片

代码:

DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title heretitle>
head>
<body>
<form action="myServlet" method="post" >
    <div class="content">
                用户名:<input type="text" name="username" placeholder="请输入用户名"><br/>
     div>
    <div class="content">
                密   码:<input type="password" name="password" placeholder="请输入密码"><br/>
    div>
    <div class="commit">
         <button type="submit" class="btnSubmit" style="">提交button>
    div>
form>    
body>
html>
login.html
package MyServlet;

import java.io.IOException;
import java.io.PrintWriter;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/myServlet")
public class myServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private String User;
    private String Password;
        
    /**
     * @see HttpServlet#HttpServlet()
     */
    public myServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
 
    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }
 
    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
 
        PrintWriter out=response.getWriter();
        //获取参数
        User=request.getParameter("username");
        Password=request.getParameter("password");
 
        out.print("你好 : " + User+",你的密码是:"+Password);
        out.close();
    }
 
}
Servlet.java
package MyFilter;
 
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
 
/**
 * Servlet Filter implementation class EncodingFilter
 */
@WebFilter("/EncodingFilter")
public class myFilter implements Filter {
 
    /**
     * Default constructor.
     */
    public myFilter() {
        // TODO Auto-generated constructor stub
    }
 
    /**
     * @see Filter#destroy()
     */
    public void destroy() {
        // TODO Auto-generated method stub
    }
 
    /**
     * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // TODO Auto-generated method stub
        // place your code here
        // pass the request along the filter chain
 
        request.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=UTF-8");
        chain.doFilter(request, response);
    }
 
    /**
     * @see Filter#init(FilterConfig)
     */
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }
 
}
Filter.java
xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>MessyTestdisplay-name>
  <welcome-file-list>
    <welcome-file>index.htmlwelcome-file>
    <welcome-file>index.htmwelcome-file>
    <welcome-file>index.jspwelcome-file>
    <welcome-file>default.htmlwelcome-file>
    <welcome-file>default.htmwelcome-file>
    <welcome-file>default.jspwelcome-file>
  welcome-file-list>
  <filter>
    <filter-name>myFilterfilter-name>
    <filter-class>MyFilter.myFilterfilter-class>
  filter>
  <filter-mapping>
    <filter-name>myFilterfilter-name>
    <url-pattern>/*url-pattern>
  filter-mapping>
web-app>
web.xml

 

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