Spring Boot REST 控制器 JUnit 测试指南与常见陷阱

// MyService.java
package com.test.project.service;

import com.test.project.beans.RequestModel;
import java.util.Map;

public interface MyService {
    Map<String, Object> deleteUploadedFile(RequestModel requestModel);
}

// MyServiceImpl.java (实际实现，在控制器测试中会被Mock)
package com.test.project.service;

import com.test.project.beans.RequestModel;
import org.springframework.stereotype.Service;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

@Service
public class MyServiceImpl implements MyService {
    @Override
    public Map<String, Object> deleteUploadedFile(RequestModel requestModel) {
        // 实际的业务逻辑，例如调用数据仓库
        System.out.println("Deleting file for requestData: " + requestModel.getRequestData());
        Map<String, Object> result = new HashMap<>();
        result.put("status", "success");
        result.put("message", "File deleted successfully for " + requestModel.getRequestData());
        return result;
    }
}

// RequestModel.java
package com.test.project.beans;

public class RequestModel {
    private String requestData;

    public String getRequestData() {
        return requestData;
    }

    public void setRequestData(String requestData) {
        this.requestData = requestData;
    }
}

// MyController.java
package com.test.project.web;

import com.test.project.beans.RequestModel;
import com.test.project.service.MyService;
import org.springframework.web.bind.annotation.*;
import java.util.Map;
import java.util.HashMap;

@RestController // 使用 @RestController 更符合 RESTful API 惯例
@RequestMapping(path = "/project-files")
public class MyController {

    private final MyService service; // 依赖 MyService 接口

    // 通过构造器注入依赖
    public MyController(MyService service) {
        this.service = service;
    }

    private RequestModel setRequestModel(String params) {
        RequestModel requestModel = new RequestModel();
        requestModel.setRequestData(params);
        return requestModel;
    }

    @PostMapping("/deleteUploadedFile")
    public Map<String, Object> deleteUploadedFile(@RequestParam(value = "requestData", required = false) String params) {
        RequestModel requestModel = setRequestModel(params);
        // 调用服务层逻辑
        return service.deleteUploadedFile(requestModel);
    }
}

mockMvc.perform(requestBuilder) // 执行请求
       .andExpect(status().isOk()) // 验证HTTP状态码
       .andExpect(content().contentType(MediaType.APPLICATION_JSON)) // 验证响应内容类型
       .andExpect(jsonPath("$.status").value("success")) // 验证JSON响应体中的特定字段
       .andReturn(); // 获取 MvcResult 以进行更复杂的处理

package com.test.project.web;

import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.when;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.test.project.beans.RequestModel;
import com.test.project.service.MyService;
import java.util.HashMap;
import java.util.Map;
import org.junit.jupiter.api.BeforeEach; // 推荐使用 JUnit 5 的 BeforeEach
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.MvcResult;

// 使用 JUnit 5 的 @WebMvcTest 和 @ExtendWith(SpringExtension.class) 或直接使用 @SpringBootTest
// 对于 JUnit 4，使用 @RunWith(SpringRunner.class)
@WebMvcTest(MyController.class)
public class MyControllerTest {

    @Autowired
    private MockMvc mockMvc; // 由 @WebMvcTest 自动注入

    @MockBean // 模拟 MyController 所依赖的 MyService
    private MyService myService;

    // ObjectMapper 用于 JSON 序列化/反序列化，如果需要的话
    private ObjectMapper objectMapper = new ObjectMapper();

    @BeforeEach // JUnit 5 的 setup 方法
    void setUp() {
        // 可以在这里进行一些通用的 Mock 配置或初始化
        // 例如，如果 MyController 有其他共同依赖，可以在这里模拟
    }

    @Test
    void deleteFile_shouldReturnSuccessStatus() throws Exception {
        String requestDataParam = "test_file.txt";
        String expectedMessage = "File deleted successfully for " + requestDataParam;

        // 模拟 MyService 的行为
        Map<String, Object> serviceResult = new HashMap<>();
        serviceResult.put("status", "success");
        serviceResult.put("message", expectedMessage);
        // 当 myService.deleteUploadedFile 方法被调用时，返回 serviceResult
        when(myService.deleteUploadedFile(any(RequestModel.class)))
            .thenReturn(serviceResult);

        // 执行 POST 请求到 /project-files/deleteUploadedFile
        // 使用 .param() 方法传递 @RequestParam 参数
        MvcResult mvcResult = mockMvc.perform(post("/project-files/deleteUploadedFile")
                .param("requestData", requestDataParam) // 传递 requestData 参数
                .accept(MediaType.APPLICATION_JSON)) // 期望接受 JSON 响应
                .andExpect(status().isOk()) // 验证 HTTP 状态码为 200 OK
                .andExpect(jsonPath("$.status").value("success")) // 验证 JSON 响应体中的 status 字段
                .andExpect(jsonPath("$.message").value(expectedMessage)) // 验证 message 字段
                .andReturn();

        // 如果需要进一步解析响应内容
        String content = mvcResult.getResponse().getContentAsString();
        Map<String, Object> responseMap = objectMapper.readValue(content, Map.class);
        // 可以进行更细致的断言
        assert(responseMap.get("status").equals("success"));
        assert(responseMap.get("message").equals(expectedMessage));
    }

    @Test
    void deleteFile_shouldHandleNullRequestData() throws Exception {
        String expectedMessage = "File deleted successfully for null"; // 假设服务层处理 null
        Map<String, Object> serviceResult = new HashMap<>();
        serviceResult.put("status", "success");
        serviceResult.put("message", expectedMessage);

        when(myService.deleteUploadedFile(any(RequestModel.class)))
                .thenReturn(serviceResult);

        mockMvc.perform(post("/project-files/deleteUploadedFile")
                // 不传递 requestData 参数，因为 required = false
                .accept(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$.status").value("success"))
                .andExpect(jsonPath("$.message").value(expectedMessage));
    }
}