@Controller层自定义注解拦截request请求校验

一、背景

笔者工作中遇到一个需求，需要开发一个注解，放在controller层的类或者方法上，用以校验请求参数中(不管是url还是body体内，都要检查，有token参数，且符合校验规则就放行)是否传了一个token的参数，并且token符合一定的生成规则，符合就不予拦截，放行请求，否则拦截请求。

用法如下图所示

可以看到 @TokenCheck 注解既可以放在类上，也可以放在方法上，放在类上则对该类中的所有的方法进行拦截校验。

注意：是加了注解才会校验是否拦截，不加没有影响。

整个代码都是使用的最新springboot版本开发的，所以servlet相关的类都是使用jakarta

如果你的springboot版本比较老，请使用javax

先引入以下依赖(javax不飘红不用引入)

<dependency>

<groupId>javax.servlet</groupId>

<artifactId>javax.servlet-api</artifactId>

<version>4.0.1</version>

<scope>provided</scope>

</dependency>

我用到的第三方依赖

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.12.0</version>
</dependency>
<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.8.24</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>6.0.11</version>
</dependency>

二、TokenCheck注解

package com.example.demo.interceptorToken;
 
import java.lang.annotation.*;
 
/**
 * 是否有token
 */
@Documented
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface TokenCheck {
}

三、请求包装器RequestWrapper

主要是对request请求包装下，因为拦截器会拦截request，会读取其中的参数流，而流只能读一次，后续再用到流的读取会报错，所以用一个包装器类处理下，把流以字节形式读出来，重写了getInputStream()，后续可以重复使用。

package com.example.demo.interceptorToken;

import jakarta.servlet.ReadListener;
import jakarta.servlet.ServletInputStream;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletRequestWrapper;
import org.apache.commons.lang3.StringUtils;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;

/**
 * @author hulei
 * @date 2024/1/11 19:48
 * @Description 由于 request中getReader()和getInputStream()只能调用一次 导致在Controller @ResponseBody的时候获取不到 null 或 Stream closed
 * 在项目中，可能会出现需要针对接口参数进行校验等问题
 * 构建可重复读取inputStream的request
 */
public class RequestWrapper extends HttpServletRequestWrapper {
    // 将流保存下来
    private final byte[] requestBody;

    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        requestBody = readBytes(request.getReader());
    }

    @Override
    public ServletInputStream getInputStream() {

        final ByteArrayInputStream basic = new ByteArrayInputStream((requestBody != null && requestBody.length >0) ? requestBody : new byte[]{});

        return new ServletInputStream() {

            @Override
            public int read() {
                return basic.read();
            }

            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }
        };
    }

    @Override
    public BufferedReader getReader() {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    /**
     * 通过BufferedReader和字符编码集转换成byte数组
     */
    private byte[] readBytes(BufferedReader br) throws IOException {
        String str;
        StringBuilder retStr = new StringBuilder();
        while ((str = br.readLine()) != null) {
            retStr.append(str);
        }
        if (StringUtils.isNotBlank(retStr.toString())) {
            return retStr.toString().getBytes(StandardCharsets.UTF_8);
        }
        return null;
    }
}

四、过滤器RequestFilter

自定义请求过滤器，把请求用自定义的包装器RequestWrapper包装下，往调用下文传递，也是为了让request请求的流能多次读取

package com.example.demo.interceptorToken;
import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.NonNull;
import org.springframework.core.annotation.Order;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.support.StandardServletMultipartResolver;
import java.io.IOException;

/**
 * @author hulei
 * @date 2024/1/11 19:48
 * 自定义请求过滤器
 */
//排序优先级,最先执行的过滤器
@Order(0)
public class RequestFilter extends OncePerRequestFilter {

    //spring6.0版本后删除了CommonsMultipartResolver,使用StandardServletMultipartResolver
    //如果是spring6.0版本,此行代码不报错请使用如下
    // private CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
    private final StandardServletMultipartResolver multipartResolver = new StandardServletMultipartResolver();
    /**
     *
     */
    @Override
    protected void doFilterInternal(@NonNull HttpServletRequest request, @NonNull HttpServletResponse response, @NonNull FilterChain filterChain) throws ServletException, IOException {
        //请求参数有form_data的话，防止request.getHeaders()报已使用,单独处理
        if (request.getContentType().contains("multipart/form-data")) {
            MultipartHttpServletRequest multiReq = multipartResolver.resolveMultipart(request);
            filterChain.doFilter(multiReq, response);
        }else{
            ServletRequest requestWrapper;
            requestWrapper = new RequestWrapper(request);
            filterChain.doFilter(requestWrapper, response);
        }
    }

}

五、请求过滤器配置类TokenFilterConfig

这个很好理解，把自定义配置类注入spring容器

package com.example.demo.interceptorToken;

import jakarta.servlet.Filter;
import jakarta.servlet.FilterConfig;
import jakarta.servlet.ServletContext;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Enumeration;


/**
 * @author hulei
 * @date 2024/1/11 19:48
 * 将过滤器注入spring容器中
 */
@Configuration
public class TokenFilterConfig implements FilterConfig {
    @Bean
    Filter bodyFilter() {
        return new RequestFilter();
    }

    @Bean
    public FilterRegistrationBean<RequestFilter> filters() {
        FilterRegistrationBean<RequestFilter> filterRegistrationBean = new FilterRegistrationBean<>();
        filterRegistrationBean.setFilter((RequestFilter) bodyFilter());
        filterRegistrationBean.addUrlPatterns("/*");
        filterRegistrationBean.setName("requestFilter");
        //多个filter的时候order的数值越小 则优先级越高
        //filterRegistrationBean.setOrder(0);
        return filterRegistrationBean;
    }

    @Override
    public String getFilterName() {
        return null;
    }

    @Override
    public ServletContext getServletContext() {
        return null;
    }

    @Override
    public String getInitParameter(String s) {
        return null;
    }

    @Override
    public Enumeration<String> getInitParameterNames() {
        return null;
    }
}

六、核心类RequestInterceptor拦截器

注意如果你的springboot版本也是低于3.0，请继承HandlerInterceptorAdapter类，实现其中方法，基本不用改动类中的内容，只需要把implements HandlerInterceptor 改为extends HandlerInterceptorAdapter即可。

package com.example.demo.interceptorToken;

import cn.hutool.json.JSONArray;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import jakarta.servlet.ServletInputStream;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.NonNull;
import org.apache.commons.lang3.StringUtils;
import org.springframework.util.StreamUtils;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.support.StandardServletMultipartResolver;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Method;
import java.net.URLDecoder;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * @author hulei
 * @date 2024/1/11 19:48
 * 自定义请求拦截器(spring boot 3.0以下的版本,需要继承HandlerInterceptorAdapter类,de方法)
 */

public class RequestInterceptor implements HandlerInterceptor {

    /**
     * 需要从请求里验证的关键字参数名
     */
    private static final String TOKEN_STR = "token";

    /**
     * 进入拦截的方法前触发
     * 这里主要从打了注解请求中查找有没有token关键字,并且token的值是否符合一定的生成规则,是就放行,不是就拦截
     */
    @Override
    public boolean preHandle(@NonNull HttpServletRequest request,@NonNull HttpServletResponse response,@NonNull Object handler) throws Exception {
        if(handler instanceof HandlerMethod handlerMethod){
            //获取token注解
            TokenCheck tokenCheck = getTokenCheck(handlerMethod);
            //请求参数有form_data的话，防止request.getHeaders()或request.getInputStream()报已使用错误,单独处理
            if( request.getContentType() != null && request.getContentType().contains("multipart/form-data")){
                //判断当前注解是否存在
                if(tokenCheck != null){
                    final StandardServletMultipartResolver multipartResolver = new StandardServletMultipartResolver();
                    MultipartHttpServletRequest multipartHttpServletRequest = multipartResolver.resolveMultipart(request);
                    //获取全部参数,不管是params里的还是form_data里的
                    //Map<String,String[]> bodyParam = multipartHttpServletRequest.getParameterMap();
                    //直接获取token参数
                    String token = multipartHttpServletRequest.getParameter(TOKEN_STR);
                    if(!StringUtils.isEmpty(token)){
                        boolean tokenRuleValidation = tokenRuleValidation(token);
                        if(!tokenRuleValidation){
                            returnJson(response, "token校验失败");
                            return false;
                        }
                        return true;
                    }
                    returnJson(response, "token校验失败");
                    return false;
                }
            }else{
                //判断当前注解是否存在
                if (tokenCheck != null) {
                    // 获取请求方式
                    //String requestMethod = request.getMethod();
                    // 获取请求参数
                    Map<String,String> paramMap;
                    //token关键字,分别是来自url的token或者来自body中的token
                    String tokenFromUrl,tokenFromBody = "";
                    request = new RequestWrapper(request);
                    String bodyParamsStr = this.getPostParam(request);
                    tokenFromBody = getTokenFromBody(bodyParamsStr,tokenFromBody);
                    paramMap = getUrlQueryMap(request);
                    tokenFromUrl = paramMap.get(TOKEN_STR);
                    if(tokenRuleValidation(tokenFromUrl)|| tokenRuleValidation(tokenFromBody)){
                        return true;
                    }else {
                        returnJson(response, "token校验失败");
                        return false;
                    }
                }
            }
            return true;
        }
        return true;
    }

    private static TokenCheck getTokenCheck(HandlerMethod handler) {
        Method method = handler.getMethod();
        //获取方法所属的类,并获取类上的@TokenCheck注解
        Class<?> clazz = method.getDeclaringClass();
        TokenCheck tokenCheck = null;
        if(clazz.isAnnotationPresent(TokenCheck.class)){
            tokenCheck = clazz.getAnnotation(TokenCheck.class);
        }
        //类上没有注解,则从方法上再获取@TokenCheck
        tokenCheck = tokenCheck == null ? method.getAnnotation(TokenCheck.class) : tokenCheck;
        return tokenCheck;
    }

    /**
     * 从请求体获取token参数
     */
    private String getTokenFromBody(String bodyParamsStr,String tokenFromBody){
        //判断是否是json数组
        boolean isJsonArray = JSONUtil.isTypeJSONArray(bodyParamsStr);
        if(!isJsonArray){
            tokenFromBody = JSONUtil.parseObj(bodyParamsStr).getStr(TOKEN_STR);
        }else{
            JSONArray jsonArray = JSONUtil.parseArray(bodyParamsStr);
            Set<String> tokenSet = new HashSet<>();
            for (int i = 0; i < jsonArray.size(); i++) {
                JSONObject jsonObject = jsonArray.getJSONObject(i);
                if(StringUtils.isNotEmpty(jsonObject.getStr(TOKEN_STR))){
                    tokenSet.add(jsonObject.getStr(TOKEN_STR));
                }
            }
            if(!tokenSet.isEmpty()){
                tokenFromBody = tokenSet.stream().filter(this::tokenRuleValidation).findFirst().orElse("");
            }
        }
        return tokenFromBody;
    }

    /**
     * token 规则校验
     * @param token token关键字
     */
    private boolean tokenRuleValidation(String token){
        return "AAABBB".equals(token);

    }

    /**
     * 如果是get请求,则把url中的请求参数获取到,转换为map
     */
    public static Map<String, String> getUrlQueryMap(HttpServletRequest request) throws UnsupportedEncodingException {
        //获取当前请求的编码方式,用于参数value解码
        String encoding = request.getCharacterEncoding();
        String urlQueryString = request.getQueryString();
        Map<String, String> queryMap = new HashMap<>();
        String[] arrSplit;
        if (urlQueryString == null) {
            return queryMap;
        } else {
            //每个键值为一组
            arrSplit = urlQueryString.split("&");
            for (String strSplit : arrSplit) {
                String[] arrSplitEqual = strSplit.split("=");
                //解析出键值
                if (arrSplitEqual.length > 1) {
                    queryMap.put(arrSplitEqual[0],URLDecoder.decode(arrSplitEqual[1], encoding));
                } else {
                    if (!"".equals(arrSplitEqual[0])) {
                        queryMap.put(arrSplitEqual[0], "");
                    }
                }
            }
        }
        return queryMap;
    }

    /**
     * 离开拦截的方法后触发
     */
    @Override
    public void postHandle(@NonNull HttpServletRequest request,@NonNull HttpServletResponse response,@NonNull Object handler, ModelAndView modelAndView) {

    }

    /**
     * 返回
     */
    private void returnJson(HttpServletResponse response, String json) throws IOException {
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html; charset=utf-8");
        try (PrintWriter writer = response.getWriter()) {
            writer.print(json);
        }
    }

    private String getPostParam(HttpServletRequest request) throws Exception{
        RequestWrapper readerWrapper = new RequestWrapper(request);
        return StringUtils.isEmpty(getBodyParams(readerWrapper.getInputStream(), request.getCharacterEncoding())) ?
                "{}":getBodyParams(readerWrapper.getInputStream(), request.getCharacterEncoding());
    }

    /**
     * 获取POST、PUT、DELETE请求中Body参数
     *
     */
    private String getBodyParams(ServletInputStream inputStream, String charset) throws Exception {
        String body = StreamUtils.copyToString(inputStream, Charset.forName(charset));
        if (StringUtils.isEmpty(body)) {
            return "";
        }
        return body;
    }
}

七、拦截器注册InterceptorRegister

一个配置类，把自定义的拦截器注入spring

package com.example.demo.interceptorToken;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @author hulei
 * @date 2024/1/11 19:48
 * 将拦截注入spring容器
 */
@Configuration
public class InterceptorRegister implements WebMvcConfigurer {

    @Bean
    public RequestInterceptor tokenInterceptor() {
        return new RequestInterceptor();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(tokenInterceptor());
    }
}

八、总结

本例主要是自定义注解，完成请求参数的拦截校验，实际中可根据需求进行修改，如记录日志，拦截校验其他参数，修改RequestInterceptor中的拦截前方法和拦截后方法的逻辑即可

gitee地址: Token-Check-Demo: 自定义注解拦截request请求

注: 创作不易，转载请标明原作地址