Spring Boot 中 RestTemplate 的核心用法指南

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

@Configuration
public class RestTemplateConfig {
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

    @Autowired
    private RestTemplate restTemplate;

String url = "https://api.example.com/users/{id}";
Map<String, Object> params = new HashMap<>();
params.put("id", 1001);
User user = restTemplate.getForObject(url, User.class, params);

String url = "https://api.example.com/users?id=1001";
User user = restTemplate.getForObject(url, User.class);

UriComponentsBuilder builder = UriComponentsBuilder
        .fromUriString("https://api.example.com/users")
        .queryParam("name", "John")
        .queryParam("age", 25);
User user = restTemplate.getForObject(builder.toUriString(), User.class);

MultiValueMap<String, String> formData = new LinkedMultiValueMap<>();
formData.add("username", "admin");
formData.add("password", "123456");
ResponseEntity<String> response = restTemplate.postForEntity(
        "https://api.example.com/login", 
        formData, 
        String.class
);

User newUser = new User("Alice", 28);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<User> request = new HttpEntity<>(newUser, headers);
User createdUser = restTemplate.postForObject(
        "https://api.example.com/users", 
        request, 
        User.class
);

@Bean
public RestTemplate customRestTemplate() {
    return new RestTemplateBuilder()
            .setConnectTimeout(Duration.ofSeconds(5))
            .setReadTimeout(Duration.ofSeconds(10))
            .build();
}

public class LoggingInterceptor implements ClientHttpRequestInterceptor {
    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, 
            ClientHttpRequestExecution execution) throws IOException {
        logRequest(request, body);
        ClientHttpResponse response = execution.execute(request, body);
        logResponse(response);
        return response;
    }
    private void logRequest(HttpRequest request, byte[] body) {
        // 实现请求日志记录
    }
    private void logResponse(ClientHttpResponse response) {
        // 实现响应日志记录
    }
}

@Bean
public RestTemplate restTemplate() {
    RestTemplate restTemplate = new RestTemplate();
    restTemplate.setInterceptors(Collections.singletonList(new LoggingInterceptor()));
    return restTemplate;
}

@Service
public class MapService {
    @Value("${tencent.map.key}")
    private String apiKey;
    @Autowired
    private RestTemplate restTemplate;
    public DrivingRoute calculateRoute(Location start, Location end) {
        String url = "https://apis.map.qq.com/ws/direction/v1/driving/"
                + "?from={start}&to={end}&key={key}";
        Map<String, String> params = new HashMap<>();
        params.put("start", start.toString());
        params.put("end", end.toString());
        params.put("key", apiKey);
        ResponseEntity<MapResponse> response = restTemplate.getForEntity(
                url, 
                MapResponse.class, 
                params
        );
        if (response.getStatusCode() == HttpStatus.OK && 
            response.getBody().getStatus() == 0) {
            return response.getBody().getResult().getRoutes().get(0);
        }
        throw new MapServiceException("路线规划失败");
    }
}