二、tienchin健身系统技术点复现-注解限流

在上一章节写到编写 lua 脚本。基本的配置类都已经创建，下面创建一个 请求获取IP的工具类和全局异常处理即可。

1、创建工具类IpUtils

package com.yangjiapo.rate_limiter.utils;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * 获取IP方法
 *
 * @author tienchin
 */
public class IpUtils {
    /**
     * 获取客户端IP
     *
     * @param request 请求对象
     * @return IP地址
     */
    public static String getIpAddr(HttpServletRequest request) {
        if (request == null) {
            return "unknown";
        }
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("X-Forwarded-For");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("X-Real-IP");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }

        return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : getMultistageReverseProxyIp(ip);
    }

    /**
     * 检查是否为内部IP地址
     *
     * @param ip IP地址
     * @return 结果
     */
    public static boolean internalIp(String ip) {
        byte[] addr = textToNumericFormatV4(ip);
        return internalIp(addr) || "127.0.0.1".equals(ip);
    }

    /**
     * 检查是否为内部IP地址
     *
     * @param addr byte地址
     * @return 结果
     */
    private static boolean internalIp(byte[] addr) {
        if (addr == null || addr.length < 2) {
            return true;
        }
        final byte b0 = addr[0];
        final byte b1 = addr[1];
        // 10.x.x.x/8
        final byte SECTION_1 = 0x0A;
        // 172.16.x.x/12
        final byte SECTION_2 = (byte) 0xAC;
        final byte SECTION_3 = (byte) 0x10;
        final byte SECTION_4 = (byte) 0x1F;
        // 192.168.x.x/16
        final byte SECTION_5 = (byte) 0xC0;
        final byte SECTION_6 = (byte) 0xA8;
        switch (b0) {
            case SECTION_1:
                return true;
            case SECTION_2:
                if (b1 >= SECTION_3 && b1 <= SECTION_4) {
                    return true;
                }
            case SECTION_5:
                switch (b1) {
                    case SECTION_6:
                        return true;
                }
            default:
                return false;
        }
    }

    /**
     * 将IPv4地址转换成字节
     *
     * @param text IPv4地址
     * @return byte 字节
     */
    public static byte[] textToNumericFormatV4(String text) {
        if (text.length() == 0) {
            return null;
        }

        byte[] bytes = new byte[4];
        String[] elements = text.split("\\.", -1);
        try {
            long l;
            int i;
            switch (elements.length) {
                case 1:
                    l = Long.parseLong(elements[0]);
                    if ((l < 0L) || (l > 4294967295L)) {
                        return null;
                    }
                    bytes[0] = (byte) (int) (l >> 24 & 0xFF);
                    bytes[1] = (byte) (int) ((l & 0xFFFFFF) >> 16 & 0xFF);
                    bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                    bytes[3] = (byte) (int) (l & 0xFF);
                    break;
                case 2:
                    l = Integer.parseInt(elements[0]);
                    if ((l < 0L) || (l > 255L)) {
                        return null;
                    }
                    bytes[0] = (byte) (int) (l & 0xFF);
                    l = Integer.parseInt(elements[1]);
                    if ((l < 0L) || (l > 16777215L)) {
                        return null;
                    }
                    bytes[1] = (byte) (int) (l >> 16 & 0xFF);
                    bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                    bytes[3] = (byte) (int) (l & 0xFF);
                    break;
                case 3:
                    for (i = 0; i < 2; ++i) {
                        l = Integer.parseInt(elements[i]);
                        if ((l < 0L) || (l > 255L)) {
                            return null;
                        }
                        bytes[i] = (byte) (int) (l & 0xFF);
                    }
                    l = Integer.parseInt(elements[2]);
                    if ((l < 0L) || (l > 65535L)) {
                        return null;
                    }
                    bytes[2] = (byte) (int) (l >> 8 & 0xFF);
                    bytes[3] = (byte) (int) (l & 0xFF);
                    break;
                case 4:
                    for (i = 0; i < 4; ++i) {
                        l = Integer.parseInt(elements[i]);
                        if ((l < 0L) || (l > 255L)) {
                            return null;
                        }
                        bytes[i] = (byte) (int) (l & 0xFF);
                    }
                    break;
                default:
                    return null;
            }
        } catch (NumberFormatException e) {
            return null;
        }
        return bytes;
    }

    /**
     * 获取IP地址
     *
     * @return 本地IP地址
     */
    public static String getHostIp() {
        try {
            return InetAddress.getLocalHost().getHostAddress();
        } catch (UnknownHostException e) {
        }
        return "127.0.0.1";
    }

    /**
     * 获取主机名
     *
     * @return 本地主机名
     */
    public static String getHostName() {
        try {
            return InetAddress.getLocalHost().getHostName();
        } catch (UnknownHostException e) {
        }
        return "未知";
    }

    /**
     * 从多级反向代理中获得第一个非unknown IP地址
     *
     * @param ip 获得的IP地址
     * @return 第一个非unknown IP地址
     */
    public static String getMultistageReverseProxyIp(String ip) {
        // 多级反向代理检测
        if (ip != null && ip.indexOf(",") > 0) {
            final String[] ips = ip.trim().split(",");
            for (String subIp : ips) {
                if (false == isUnknown(subIp)) {
                    ip = subIp;
                    break;
                }
            }
        }
        return ip;
    }

    /**
     * 检测给定字符串是否为未知，多用于检测HTTP请求相关
     *
     * @param checkString 被检测的字符串
     * @return 是否未知
     */
    public static boolean isUnknown(String checkString) {
        return checkString == null || checkString.length() == 0 || "unknown".equalsIgnoreCase(checkString);
    }
}

对于每个从前端的请求，我们都可以获取Servlet，比如

HttpServletRequest request = (HttpServletRequest)(RequestContextHolder.getRequestArributes()).getRequest();

2、创建全局异常处理类

对于 @RateLimiter 注解 拦截产生的异常，应该有个自定义异常。然后再全局异常处理中把数据抛给前端。

public class RateLimitException extends Exception {

    public RateLimitException(String message) {
        super(message);
    }
}

/**
 * 功能描述 全局的异常处理
 *
 * @author [山沉]
 * @个人博客 [https://choleen95.github.io/]
 * @博客 [https://www.cnblogs.com/Choleen/]
 * @since [2023/6/6 0:09]
 */
@RestControllerAdvice
public class GlobalException {

    @ExceptionHandler(RateLimitException.class)
    public Map<Object, Object> rateLimitException(RateLimitException rateLimitException) {
        Map<Object, Object> map = new HashMap<>();
        map.put("status", 500);
        map.put("msg", rateLimitException.getMessage());
        return map;
    }
}

3、测试是否拦截成功

创建一个 HelloController类，定义一个 /hello 接口。

在方法上定义一个注解 @RateLimiter(time=10,count=3,limitType=LimitType.IP) 10秒内请求超过3次即限制请求后台，采用

rate_limiter:192.168.246.214:com.yangjiapo.rate_limiter.controller.HelloController.hello 形式的key组成方式，此处 LimitType.IP

即是否构建IP到 key 中。在 切面拦截前置通知中 判断。

@RestController
public class HelloController {

    @RateLimiter(count = 3, time = 10, limitType = LimitType.IP)
    @GetMapping("/hello")
    public String hello() {
        return "hello";
    }
}

4、设置PostMan 循环请求

还差一步，就是把左边请求拖到右边 RUN ORDER

点击开始，如下为控制台输出

成功