// 調(diào)用第三方支付接口
public String createOrder(String orderId) {
    // 1. 創(chuàng)建RestTemplate（重復(fù)10次）
    RestTemplate restTemplate = new RestTemplate();
    
    // 2. 設(shè)置超時(shí)（重復(fù)10次）
    SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
    factory.setConnectTimeout(3000);
    factory.setReadTimeout(3000);
    restTemplate.setRequestFactory(factory);
    
    // 3. 添加認(rèn)證頭（重復(fù)10次）
    HttpHeaders headers = new HttpHeaders();
    headers.set("Authorization", "Bearer " + getToken());
    HttpEntity<String> entity = new HttpEntity<>(headers);
    
    // 4. 記錄日志（重復(fù)10次）
    log.info("請(qǐng)求支付接口: {}", orderId);
    try {
        String result = restTemplate.postForObject(PAY_URL, entity, String.class);
        log.info("請(qǐng)求成功: {}", result);
        return result;
    } catch (Exception e) {
        log.error("請(qǐng)求失敗", e);
        // 5. 重試（重復(fù)10次）
        for (int i = 0; i < 2; i++) {
            try {
                return restTemplate.postForObject(PAY_URL, entity, String.class);
            } catch (Exception ex) { /* 重試邏輯 */ }
        }
        throw e;
    }
}

// 重構(gòu)后：一行搞定所有通用邏輯
return restTemplate.postForObject(PAY_URL, entity, String.class);

public interface ClientHttpRequestInterceptor {
    // request：請(qǐng)求對(duì)象（可修改請(qǐng)求頭、參數(shù)）
    // body：請(qǐng)求體字節(jié)數(shù)組
    // execution：執(zhí)行器（用于調(diào)用下一個(gè)攔截器）
    ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException;
}

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.util.StreamUtils;

import java.io.IOException;
import java.nio.charset.StandardCharsets;

@Slf4j
public class LoggingInterceptor implements ClientHttpRequestInterceptor {
    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        // 1. 記錄請(qǐng)求信息
        long start = System.currentTimeMillis();
        log.info("===== 請(qǐng)求開始 =====");
        log.info("URL: {}", request.getURI());
        log.info("Method: {}", request.getMethod());
        log.info("Headers: {}", request.getHeaders());
        log.info("Body: {}", new String(body, StandardCharsets.UTF_8));

        // 2. 執(zhí)行下一個(gè)攔截器（關(guān)鍵！不調(diào)用會(huì)中斷鏈條）
        ClientHttpResponse response = execution.execute(request, body);

        // 3. 記錄響應(yīng)信息
        String responseBody = StreamUtils.copyToString(response.getBody(), StandardCharsets.UTF_8);
        log.info("===== 請(qǐng)求結(jié)束 =====");
        log.info("Status: {}", response.getStatusCode());
        log.info("Headers: {}", response.getHeaders());
        log.info("Body: {}", responseBody);
        log.info("耗時(shí): {}ms", System.currentTimeMillis() - start);

        return response;
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.BufferingClientHttpRequestFactory;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class RestTemplateConfig {

    @Bean
    public RestTemplate customRestTemplate() {
        // 1. 創(chuàng)建攔截器列表（順序很重要?。?
        List<ClientHttpRequestInterceptor> interceptors = new ArrayList<>();
        interceptors.add(new AuthInterceptor());       // 1. 認(rèn)證攔截器（先加請(qǐng)求頭）
        interceptors.add(new LoggingInterceptor());    // 2. 日志攔截器（記錄完整請(qǐng)求）
        interceptors.add(new RetryInterceptor(2));     // 3. 重試攔截器（最后處理失敗）

        // 2. 創(chuàng)建RestTemplate并設(shè)置攔截器
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setInterceptors(interceptors);

        // 3. 解決響應(yīng)流只能讀取一次的問(wèn)題（關(guān)鍵配置?。?
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        factory.setConnectTimeout(3000);  // 連接超時(shí)3秒
        factory.setReadTimeout(3000);     // 讀取超時(shí)3秒
        restTemplate.setRequestFactory(new BufferingClientHttpRequestFactory(factory));

        return restTemplate;
    }
}

AuthInterceptor → LoggingInterceptor → RetryInterceptor → 實(shí)際請(qǐng)求 → RetryInterceptor → LoggingInterceptor → AuthInterceptor

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 java.io.IOException;

public class AuthInterceptor implements ClientHttpRequestInterceptor {
    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        // 1. 從緩存獲取Token（實(shí)際項(xiàng)目可能從Redis或配置中心獲?。?
        String token = getToken();
        
        // 2. 添加Authorization請(qǐng)求頭
        HttpHeaders headers = request.getHeaders();
        headers.set("Authorization", "Bearer " + token);  // Bearer認(rèn)證格式
        
        // 3. 傳遞給下一個(gè)攔截器
        return execution.execute(request, body);
    }

    // 模擬從緩存獲取Token
    private String getToken() {
        return "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...";  // 實(shí)際項(xiàng)目是真實(shí)Token
    }
}

package com.example.rest;

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.web.client.HttpStatusCodeException;

import java.io.IOException;

@Slf4j
public class RetryInterceptor implements ClientHttpRequestInterceptor {
    private final int maxRetries;  // 最大重試次數(shù)

    public RetryInterceptor(int maxRetries) {
        this.maxRetries = maxRetries;
    }

    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        int retryCount = 0;
        while (true) {
            try {
                // 執(zhí)行請(qǐng)求（調(diào)用下一個(gè)攔截器或?qū)嶋H請(qǐng)求）
                return execution.execute(request, body);
            } catch (HttpStatusCodeException e) {
                // 只對(duì)5xx服務(wù)器錯(cuò)誤重試（業(yè)務(wù)錯(cuò)誤不重試）
                if (e.getStatusCode().is5xxServerError() && retryCount < maxRetries) {
                    retryCount++;
                    log.warn("服務(wù)器錯(cuò)誤，開始第{}次重試，狀態(tài)碼:{}", retryCount, e.getStatusCode());
                    continue;
                }
                throw e;  // 非5xx錯(cuò)誤或達(dá)到最大重試次數(shù)
            } catch (IOException e) {
                // 網(wǎng)絡(luò)異常重試（如連接超時(shí)、DNS解析失?。?
                if (retryCount < maxRetries) {
                    retryCount++;
                    log.warn("網(wǎng)絡(luò)異常，開始第{}次重試", retryCount, e);
                    continue;
                }
                throw e;
            }
        }
    }
}

// 創(chuàng)建支持響應(yīng)緩存的工廠（已在3.1節(jié)配置中體現(xiàn)）
SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
BufferingClientHttpRequestFactory bufferingFactory = new BufferingClientHttpRequestFactory(factory);
restTemplate.setRequestFactory(bufferingFactory);

public class BadInterceptor implements ClientHttpRequestInterceptor {
    private int count = 0;  // ? 多線程共享變量，會(huì)導(dǎo)致計(jì)數(shù)錯(cuò)誤
    
    @Override
    public ClientHttpResponse intercept(...) {
        count++;  // 危險(xiǎn)！多線程下count值不準(zhǔn)
        // ...
    }
}

package com.example.rest;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class TestController {

    @Autowired
    private RestTemplate customRestTemplate;  // 注入自定義的RestTemplate

    @GetMapping("/call-api")
    public String callThirdApi() {
        // 調(diào)用第三方API，攔截器自動(dòng)處理認(rèn)證、日志、重試
        return customRestTemplate.getForObject("http://localhost:8080/mock-third-api", String.class);
    }

    // 模擬一個(gè)三方接口
    @GetMapping("/mock-third-api")
    public String mockThirdApi() {
        return "hello";
    }
}

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>