Java后端接收前端数据的五种方法

axios.post('/api/user', {
  username: 'john',
  age: 30
})

@PostMapping("/api/user")
public User createUser(@RequestBody User user) {
    // 处理接收到的user对象
    return user;
}

public class User {
    private String username;
    private Integer age;
    
    // getters and setters
}

const formData = new FormData();
formData.append('username', 'john');
formData.append('age', 30);
 
axios.post('/api/user', formData, {
  headers: {
    'Content-Type': 'multipart/form-data'
  }
})

@PostMapping("/api/user")
public User createUser(
    @RequestParam("username") String username,
    @RequestParam("age") Integer age
) {
    User user = new User();
    user.setUsername(username);
    user.setAge(age);
    return user;
}

axios.get('/api/user?username=john&age=30') 

@GetMapping("/api/user")
public User getUser(
    @RequestParam("username") String username,
    @RequestParam("age") Integer age
) {
    User user = new User();
    user.setUsername(username);
    user.setAge(age);
    return user;
}

const formData = new FormData();
formData.append('file', file); // file是文件对象
 
axios.post('/api/upload', formData, {
  headers: {
    'Content-Type': 'multipart/form-data'
  }
})

@PostMapping("/api/upload")
public String handleFileUpload(@RequestParam("file") MultipartFile file) {
    if (!file.isEmpty()) {
        try {
            // 处理文件上传
            byte[] bytes = file.getBytes();
            // 保存文件等操作
            return "上传成功";
        } catch (Exception e) {
            return "上传失败: " + e.getMessage();
        }
    } else {
        return "上传失败，因为文件为空";
    }
}

axios.get('/api/user/123') 

@GetMapping("/api/user/{id}")
public User getUser(@PathVariable("id") Long id) {
    // 根据id获取用户
    User user = userService.getUserById(id);
    return user;
}