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feign中RequestInterceptor的原理和作用

发表于：2025-02-02 作者：千家信息网编辑

千家信息网最后更新 2025年02月02日，这篇文章主要讲解了"feign中RequestInterceptor的原理和作用"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"feign中Reques

千家信息网最后更新 2025年02月02日feign中RequestInterceptor的原理和作用

这篇文章主要讲解了"feign中RequestInterceptor的原理和作用"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"feign中RequestInterceptor的原理和作用"吧！

序

本文主要研究一下feign的RequestInterceptor

RequestInterceptor

feign-core-10.2.3-sources.jar!/feign/RequestInterceptor.java

public interface RequestInterceptor {  /**   * Called for every request. Add data using methods on the supplied {@link RequestTemplate}.   */  void apply(RequestTemplate template);}

RequestInterceptor接口定义了apply方法，其参数为RequestTemplate；它有一个抽象类为BaseRequestInterceptor，还有几个实现类分别为BasicAuthRequestInterceptor、FeignAcceptGzipEncodingInterceptor、FeignContentGzipEncodingInterceptor

BasicAuthRequestInterceptor

feign-core-10.2.3-sources.jar!/feign/auth/BasicAuthRequestInterceptor.java

public class BasicAuthRequestInterceptor implements RequestInterceptor {  private final String headerValue;  /**   * Creates an interceptor that authenticates all requests with the specified username and password   * encoded using ISO-8859-1.   *   * @param username the username to use for authentication   * @param password the password to use for authentication   */  public BasicAuthRequestInterceptor(String username, String password) {    this(username, password, ISO_8859_1);  }  /**   * Creates an interceptor that authenticates all requests with the specified username and password   * encoded using the specified charset.   *   * @param username the username to use for authentication   * @param password the password to use for authentication   * @param charset the charset to use when encoding the credentials   */  public BasicAuthRequestInterceptor(String username, String password, Charset charset) {    checkNotNull(username, "username");    checkNotNull(password, "password");    this.headerValue = "Basic " + base64Encode((username + ":" + password).getBytes(charset));  }  /*   * This uses a Sun internal method; if we ever encounter a case where this method is not   * available, the appropriate response would be to pull the necessary portions of Guava's   * BaseEncoding class into Util.   */  private static String base64Encode(byte[] bytes) {    return Base64.encode(bytes);  }  @Override  public void apply(RequestTemplate template) {    template.header("Authorization", headerValue);  }}

BasicAuthRequestInterceptor实现了RequestInterceptor接口，其apply方法往RequestTemplate添加名为Authorization的header

BaseRequestInterceptor

spring-cloud-openfeign-core-2.2.0.M1-sources.jar!/org/springframework/cloud/openfeign/encoding/BaseRequestInterceptor.java

public abstract class BaseRequestInterceptor implements RequestInterceptor {        /**         * The encoding properties.         */        private final FeignClientEncodingProperties properties;        /**         * Creates new instance of {@link BaseRequestInterceptor}.         * @param properties the encoding properties         */        protected BaseRequestInterceptor(FeignClientEncodingProperties properties) {                Assert.notNull(properties, "Properties can not be null");                this.properties = properties;        }        /**         * Adds the header if it wasn't yet specified.         * @param requestTemplate the request         * @param name the header name         * @param values the header values         */        protected void addHeader(RequestTemplate requestTemplate, String name,                        String... values) {                if (!requestTemplate.headers().containsKey(name)) {                        requestTemplate.header(name, values);                }        }        protected FeignClientEncodingProperties getProperties() {                return this.properties;        }}

BaseRequestInterceptor定义了addHeader方法，往requestTemplate添加非重名的header

FeignAcceptGzipEncodingInterceptor

spring-cloud-openfeign-core-2.2.0.M1-sources.jar!/org/springframework/cloud/openfeign/encoding/FeignAcceptGzipEncodingInterceptor.java

public class FeignAcceptGzipEncodingInterceptor extends BaseRequestInterceptor {        /**         * Creates new instance of {@link FeignAcceptGzipEncodingInterceptor}.         * @param properties the encoding properties         */        protected FeignAcceptGzipEncodingInterceptor(                        FeignClientEncodingProperties properties) {                super(properties);        }        /**         * {@inheritDoc}         */        @Override        public void apply(RequestTemplate template) {                addHeader(template, HttpEncoding.ACCEPT_ENCODING_HEADER,                                HttpEncoding.GZIP_ENCODING, HttpEncoding.DEFLATE_ENCODING);        }}

FeignAcceptGzipEncodingInterceptor继承了BaseRequestInterceptor，它的apply方法往RequestTemplate添加了名为Accept-Encoding，值为gzip,deflate的header

FeignContentGzipEncodingInterceptor

spring-cloud-openfeign-core-2.2.0.M1-sources.jar!/org/springframework/cloud/openfeign/encoding/FeignContentGzipEncodingInterceptor.java

public class FeignContentGzipEncodingInterceptor extends BaseRequestInterceptor {        /**         * Creates new instance of {@link FeignContentGzipEncodingInterceptor}.         * @param properties the encoding properties         */        protected FeignContentGzipEncodingInterceptor(                        FeignClientEncodingProperties properties) {                super(properties);        }        /**         * {@inheritDoc}         */        @Override        public void apply(RequestTemplate template) {                if (requiresCompression(template)) {                        addHeader(template, HttpEncoding.CONTENT_ENCODING_HEADER,                                        HttpEncoding.GZIP_ENCODING, HttpEncoding.DEFLATE_ENCODING);                }        }        /**         * Returns whether the request requires GZIP compression.         * @param template the request template         * @return true if request requires compression, false otherwise         */        private boolean requiresCompression(RequestTemplate template) {                final Map> headers = template.headers();                return matchesMimeType(headers.get(HttpEncoding.CONTENT_TYPE))                                && contentLengthExceedThreshold(headers.get(HttpEncoding.CONTENT_LENGTH));        }        /**         * Returns whether the request content length exceed configured minimum size.         * @param contentLength the content length header value         * @return true if length is grater than minimum size, false otherwise         */        private boolean contentLengthExceedThreshold(Collection contentLength) {                try {                        if (contentLength == null || contentLength.size() != 1) {                                return false;                        }                        final String strLen = contentLength.iterator().next();                        final long length = Long.parseLong(strLen);                        return length > getProperties().getMinRequestSize();                }                catch (NumberFormatException ex) {                        return false;                }        }        /**         * Returns whether the content mime types matches the configures mime types.         * @param contentTypes the content types         * @return true if any specified content type matches the request content types         */        private boolean matchesMimeType(Collection contentTypes) {                if (contentTypes == null || contentTypes.size() == 0) {                        return false;                }                if (getProperties().getMimeTypes() == null                                || getProperties().getMimeTypes().length == 0) {                        // no specific mime types has been set - matching everything                        return true;                }                for (String mimeType : getProperties().getMimeTypes()) {                        if (contentTypes.contains(mimeType)) {                                return true;                        }                }                return false;        }}

FeignContentGzipEncodingInterceptor继承了BaseRequestInterceptor，其apply方法先判断是否需要compression，即mimeType是否符合要求以及content大小是否超出阈值，需要compress的话则添加名为Content-Encoding，值为gzip,deflate的header

小结

RequestInterceptor接口定义了apply方法，其参数为RequestTemplate；它有一个抽象类为BaseRequestInterceptor，还有几个实现类分别为BasicAuthRequestInterceptor、FeignAcceptGzipEncodingInterceptor、FeignContentGzipEncodingInterceptor
BasicAuthRequestInterceptor实现了RequestInterceptor接口，其apply方法往RequestTemplate添加名为Authorization的header
BaseRequestInterceptor定义了addHeader方法，往requestTemplate添加非重名的header；FeignAcceptGzipEncodingInterceptor继承了BaseRequestInterceptor，它的apply方法往RequestTemplate添加了名为Accept-Encoding，值为gzip,deflate的header；FeignContentGzipEncodingInterceptor继承了BaseRequestInterceptor，其apply方法先判断是否需要compression，即mimeType是否符合要求以及content大小是否超出阈值，需要compress的话则添加名为Content-Encoding，值为gzip,deflate的header

感谢各位的阅读，以上就是"feign中RequestInterceptor的原理和作用"的内容了，经过本文的学习后，相信大家对feign中RequestInterceptor的原理和作用这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是，小编将为大家推送更多相关知识点的文章，欢迎关注！

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