一 RestTemplate 为什么集成拦截器

Spring RestTemplate 经常被用作客户端向 Restful API 发送各种请求，在开发过程中我们会发现很多请求都会有相同的场景，如请求携带认证的 token、验证的签名、打印请求和响应日志等。在请求方法里面添加这些通用的非业务逻辑，代码显得很冗余。

这个时候我们就思考，我们是不是就可以将这些非业务性代码抽取出来进行复用。

Spring 提供了 ClientHttpRequestInterceptor 接口，可以对请求进行拦截，并在其被发送至服务端之前修改请求或是增强相应的信息。
 

二 RestTemplate 如何集成拦截器

2.1 实现 ClientHttpRequestInterceptor 接口

LogInterceptor 代码

import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpRequest;
import org.springframework.http.client.ClientHttpRequestExecution;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.util.Optional;

@Slf4j
@Component
public class LogInterceptor implements ClientHttpRequestInterceptor {

    @Override
    public ClientHttpResponse intercept(HttpRequest httpRequest, byte[] bytes, ClientHttpRequestExecution clientHttpRequestExecution) throws IOException {
        ClientHttpResponse response = clientHttpRequestExecution.execute(httpRequest, bytes);
        log.info("request = {}, requestBody = {}, response = {}", httpRequest,
                Optional.of(bytes).map(String::new).orElse(""), response);
        return response;
    }
}

TokenInterceptor 代码

import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpRequest;
import org.springframework.http.client.ClientHttpRequestExecution;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Slf4j
@Component
public class TokenInterceptor implements ClientHttpRequestInterceptor {

    @Override
    public ClientHttpResponse intercept(HttpRequest httpRequest, byte[] bytes, ClientHttpRequestExecution clientHttpRequestExecution) throws IOException {
        HttpHeaders headers = httpRequest.getHeaders();
        headers.add("Authorization", "token");
        return clientHttpRequestExecution.execute(httpRequest, bytes);
    }
}

 2.2 拦截器增加到 RestTemplate 实例

import com.google.common.collect.Lists;
import com.lhh.demo.interceptor.LogInterceptor;
import com.lhh.demo.interceptor.TokenInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.web.client.RestTemplate;

import java.util.List;

@Configuration
public class RestTemplateConfig {

    @Autowired
    private LogInterceptor logInterceptor;

    @Autowired
    private TokenInterceptor tokenInterceptor;
    
    @Bean
    public RestTemplate restTemplate() {
        RestTemplate restTemplate = new RestTemplate();
        List<ClientHttpRequestInterceptor> interceptorList = Lists.newArrayList();
        // 增加多个拦截器，多个拦截器按照顺序执行
        interceptorList.add(tokenInterceptor);
        interceptorList.add(logInterceptor);
        restTemplate.setInterceptors(interceptorList);
        return restTemplate;
    }
}

 2.3 RestTemplate 的使用

SpringBoot 集成 RestTemplate 和使用_新猿一马的博客-CSDN博客_resttemplate 依赖目录一 RestTemplate 依赖二 RestTemplate 装配三RestTemplate 使用一 RestTemplate 依赖<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starte...https://blog.csdn.net/jack1liu/article/details/105572375