简单的Filter实现

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原创最新推荐文章于 2026-07-09 15:49:56 发布 1.2k 阅读 AI 写同款· GEO 优化 ›

Spring Boot实战之Filter实现简单的Http Basic认证 Spring Boot实战之Filter 本文在上一篇文章http://blog.youkuaiyun.com/sun_t89/article/details/51912905 的基础上，给每个rest接口上添加过滤器，使用过滤器实现简单的Http Basic认证 1、Filter功能 filter功能，它使用户可以改变一个 request和修改一个response. Filter 不是阅读详情

1.在xml文件配置过滤器

<?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>Filter</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

    <error-page>
        <error-code>404</error-code>
        <location>/error.jsp</location>
    </error-page>
    <error-page>
        <error-code>500</error-code>
        <location>/error.jsp</location>
    </error-page>
    <filter>
        <filter-name>CharsetFilter</filter-name>
        <filter-class>com.test.filter.CharsetFilter</filter-class>
        <init-param>
            <param-name>charset</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter>
        <filter-name>LoginFilter</filter-name>
        <filter-class>com.test.filter.LoginFilter</filter-class>
        <init-param>
            <param-name>noLoginPath</param-name>
            <param-value>login.jsp;error.jsp;index.jsp</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>LoginFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    <filter>
        <filter-name>ErrorFilter</filter-name>
        <filter-class>com.test.filter.ErrorFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>ErrorFilter</filter-name>
        <url-pattern>/error.jsp</url-pattern>
        <dispatcher>ERROR</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>CharsetFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>


</web-app>

2.建立java类实现Filter接口

1.编码转换案例

package com.test.filter;

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;

public class CharsetFilter implements Filter{
    private FilterConfig config;
    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        String charset = config.getInitParameter("charset");
        if(charset == null || charset.equals("")){
            charset = "UTF-8";
        }
        request.setCharacterEncoding(charset);
        response.setCharacterEncoding(charset);
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        config = arg0;
    }

}

2.错误显示案例

package com.test.filter;

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;

public class ErrorFilter implements Filter{

    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain chain) throws IOException, ServletException {
            System.out.println("error!!!!");
            chain.doFilter(arg0, arg1);

    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub

    }


}

3.登录过滤案例

package com.test.filter;

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.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginFilter implements Filter{
    private FilterConfig config;
    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)arg0;
        HttpServletResponse response = (HttpServletResponse)arg1;
        HttpSession session = request.getSession();

        //获取不用过滤的路径
        String noLoginPath = config.getInitParameter("noLoginPath");
        //对于不用过滤的路径直接放行
        if(noLoginPath != null){
            String[] strArray = noLoginPath.split(";");

            for(String str:strArray){
                if(str == null || str.equals(""))   continue;
                if(request.getRequestURI().indexOf(str) != -1){
                    chain.doFilter(arg0, arg1);
                    return;
                }
            }
        }
        //如果session中没有用户信息就跳转到登陆界面，否则放行
        if(session.getAttribute("user") == null){
            response.sendRedirect("login.jsp");
        }else{
            chain.doFilter(arg0, arg1);
        }
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
        config = arg0;
    }

}

3.建立过滤后显示的页面

1.编码转换案例

package com.test.filter;

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;

public class CharsetFilter implements Filter{
    private FilterConfig config;
    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        String charset = config.getInitParameter("charset");
        if(charset == null || charset.equals("")){
            charset = "UTF-8";
        }
        request.setCharacterEncoding(charset);
        response.setCharacterEncoding(charset);
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        config = arg0;
    }

}

2.错误显示页面

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'error.jsp' starting page</title>

    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>

  <body>
    This is my error page. <br>
  </body>
</html>

3.登录过滤页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">

    <title>My JSP 'success.jsp' starting page</title>

    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->

  </head>

  <body>
    <span><%=request.getParameter("userName") %></span>
    <%System.out.println("userName is "+request.getParameter("userName")); %>
    <span><%=request.getParameter("password") %></span>
    <%System.out.println("pssword is "+request.getParameter("password")); %>
  </body>
</html>