Springboot提供外部接口和访问外部接口的简单例子

1. 创建Spring Boot控制器

首先，我们将创建一个Spring Boot控制器来提供API接口。

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api")
public class UserController {

    // 假设这里有一个服务来获取用户信息，这里使用模拟数据代替
    private final UserService userService = new UserService();

    @GetMapping("/user")
    public ResponseEntity<?> getUserByMemberNumAndTel(@RequestParam String memberNum, @RequestParam String tel) {
        if (memberNum == null || tel == null || memberNum.trim().isEmpty() || tel.trim().isEmpty()) {
            return ResponseEntity.badRequest().body("Invalid request: memberNum and tel are required");
        }

        User user = userService.findUserByMemberNumAndTel(memberNum, tel);

        if (user == null) {
            return ResponseEntity.status(HttpStatus.NOT_FOUND).body("User not found");
        }

        return ResponseEntity.ok().body(new UserResponse(user.getUsername(), user.getEmail(), user.getAddress()));
    }

用户实体类

private static class User {
        private String username;
        private String email;
        private String address;

        public User(String username, String email, String address) {
            this.username = username;
            this.email = email;
            this.address = address;
        }

        // Getters and setters
        public String getUsername() { return username; }
        public String getEmail() { return email; }
        public String getAddress() { return address; }
    }

用户响应类

private static class UserResponse {
        private final String username;
        private final String email;
        private final String address;

        public UserResponse(String username, String email, String address) {
            this.username = username;
            this.email = email;
            this.address = address;
        }

        // Getters
        public String getUsername() { return username; }
        public String getEmail() { return email; }
        public String getAddress() { return address; }
    }

服务接口

private interface UserService {
        User findUserByMemberNumAndTel(String memberNum, String tel);
    }

服务实现类

private static class UserServiceImpl implements UserService {
        @Override
        public User findUserByMemberNumAndTel(String memberNum, String tel) {
            // 这里应该是数据库查询逻辑，这里使用模拟数据
            if ("123456".equals(memberNum) && "1234567890".equals(tel)) {
                return new User("John Doe", "john.doe@example.com", "123 Main St");
            }
            return null;
        }
    }
}

2. 编写访问API的方法

我们将编写一个方法来调用这个API，并处理返回的响应。如果访问超时（30秒），将抛出访问超时的错误。

import org.springframework.web.client.RestTemplate;
import org.springframework.web.client.ResourceAccessException;

public class ApiClient {

    private final RestTemplate restTemplate;

    public ApiClient() {
        this.restTemplate = new RestTemplate();
        // 设置超时时间为30秒
        restTemplate.setRequestFactory(new SimpleClientHttpRequestFactory() {{
            setConnectTimeout(30000);
            setReadTimeout(30000);
        }});
    }

    public UserResponse getUserByMemberNumAndTel(String memberNum, String tel) {
        try {
            ResponseEntity<UserResponse> response = restTemplate.getForEntity(
                    "http://localhost:8080/api/user?memberNum={memberNum}&tel={tel}",
                    UserResponse.class,
                    memberNum,
                    tel
            );

            if (response.getStatusCode() == HttpStatus.OK) {
                return response.getBody();
            } else if (response.getStatusCode() == HttpStatus.BAD_REQUEST) {
                throw new IllegalArgumentException("Invalid request: " + response.getBody());
            } else if (response.getStatusCode() == HttpStatus.NOT_FOUND) {
                throw new RuntimeException("User not found");
            }
        } catch (ResourceAccessException e) {
            throw new RuntimeException("访问超时，请稍后再试", e);
        }
        return null;
    }

    public static void main(String[] args) {
        ApiClient apiClient = new ApiClient();
        try {
            UserResponse userResponse = apiClient.getUserByMemberNumAndTel("123456", "1234567890");

            if (userResponse != null) {
                System.out.println("User Info:");
                System.out.println("Username: " + userResponse.getUsername());
                System.out.println("Email: " + userResponse.getEmail());
                System.out.println("Address: " + userResponse.getAddress());
            } else {
                System.out.println("Failed to retrieve user info.");
            }
        } catch (RuntimeException e) {
            System.out.println(e.getMessage());
        }
    }
}

在这个例子中，ApiClient类有一个方法getUserByMemberNumAndTel，它使用RestTemplate来调用我们之前创建的API。这个方法接受会员账号和电话作为参数，然后发送GET请求到API端点。根据响应的状态码，它将返回用户信息或者抛出异常。

我们设置了RestTemplate的连接超时和读取超时时间为30秒。如果在30秒内没有收到响应，RestTemplate将抛出ResourceAccessException异常，我们捕获这个异常并抛出一个自定义的RuntimeException，提示用户访问超时。

请注意，你需要根据你的实际环境调整RestTemplate的URL，以及处理异常和错误响应的逻辑。这个例子中的main方法是一个简单的测试，用于演示如何调用getUserByMemberNumAndTel方法并打印用户信息。