首页　>　文章列表　>　莫科托示例中的thenthrow（）方法

莫科托示例中的thenthrow（）方法

285 2025-02-07

方案：模拟服务异常以测试控制器中的错误处理

1. Spring Boot 应用代码

Employee.java

package com.example.demo.model;

public class Employee {
    private String id;
    private String name;

    // constructors, getters, and setters
    public Employee(String id, String name) {
        this.id = id;
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

EmployeeNotFoundException.java

package com.example.demo.exception;

public class EmployeeNotFoundException extends RuntimeException {
    public EmployeeNotFoundException(String message) {
        super(message);
    }
}

EmployeeService.java

package com.example.demo.service;

import com.example.demo.exception.EmployeeNotFoundException;
import com.example.demo.model.Employee;
import org.springframework.stereotype.Service;

@Service
public class EmployeeService {
    public Employee getEmployeeById(String id) {
        // 模拟员工不存在时抛出异常
        if ("0".equals(id)) {
            throw new EmployeeNotFoundException("Employee not found with id: " + id);
        }
        return new Employee(id, "John Doe");
    }
}

EmployeeController.java

package com.example.demo.controller;

import com.example.demo.exception.EmployeeNotFoundException;
import com.example.demo.model.Employee;
import com.example.demo.service.EmployeeService;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/employees")
public class EmployeeController {
    private final EmployeeService employeeService;

    public EmployeeController(EmployeeService employeeService) {
        this.employeeService = employeeService;
    }

    @GetMapping("/{id}")
    public ResponseEntity<Employee> getEmployee(@PathVariable String id) {
        Employee employee = employeeService.getEmployeeById(id);
        return ResponseEntity.ok(employee);
    }

    // 全局异常处理
    @ExceptionHandler(EmployeeNotFoundException.class)
    public ResponseEntity<String> handleEmployeeNotFoundException(EmployeeNotFoundException ex) {
        return new ResponseEntity<>(ex.getMessage(), HttpStatus.NOT_FOUND);
    }
}

2. 使用 thenThrow() 的单元测试

EmployeeControllerTest.java

package com.example.demo.controller;

import com.example.demo.exception.EmployeeNotFoundException;
import com.example.demo.model.Employee;
import com.example.demo.service.EmployeeService;
import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.springframework.http.ResponseEntity;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;

class EmployeeControllerTest {

    @Mock
    private EmployeeService employeeService;

    @InjectMocks
    private EmployeeController employeeController;

    public EmployeeControllerTest() {
        MockitoAnnotations.openMocks(this); // 初始化 Mock 对象
    }

    @Test
    void testGetEmployee_Success() {
        // Arrange: 模拟服务方法返回一个 Employee 对象
        when(employeeService.getEmployeeById("1")).thenReturn(new Employee("1", "John Doe"));

        // Act: 调用控制器方法
        ResponseEntity<Employee> response = employeeController.getEmployee("1");

        // Assert: 验证响应是否正确
        assertNotNull(response);
        assertEquals(200, response.getStatusCodeValue());
        assertEquals("John Doe", response.getBody().getName());

        // 验证服务方法被调用了一次
        verify(employeeService, times(1)).getEmployeeById("1");
    }

    @Test
    void testGetEmployee_ThrowsException() {
        // Arrange: 模拟服务方法抛出异常
        when(employeeService.getEmployeeById("0")).thenThrow(new EmployeeNotFoundException("Employee not found with id: 0"));

        // Act & Assert: 验证异常是否被正确处理
        assertThrows(EmployeeNotFoundException.class, () -> {
            employeeController.getEmployee("0");
        });

        // 验证服务方法被调用了一次
        verify(employeeService, times(1)).getEmployeeById("0");
    }
}

说明:

thenThrow() 的用法：when(employeeService.getEmployeeById("0")).thenThrow(new EmployeeNotFoundException("Employee not found with id: 0")); 这行代码模拟了当 getEmployeeById 方法传入 "0" 时抛出 EmployeeNotFoundException 异常。

单元测试包含两个测试用例：