使用@PATCH方法进行Spring REST部分更新

Question

我正在尝试基于以下内容实现Manager实体的部分更新:

实体

public class Manager {
    private int id;
    private String firstname;
    private String lastname;
    private String username;
    private String password;

    // getters and setters omitted
}

Controller中的SaveManager方法

@RequestMapping(value = "/save", method = RequestMethod.PATCH)
public @ResponseBody void saveManager(@RequestBody Manager manager){
    managerService.saveManager(manager);
}

在Dao impl中保存对象管理器.

@Override
public void saveManager(Manager manager) {  
    sessionFactory.getCurrentSession().saveOrUpdate(manager);
}

保存对象时,用户名和密码已正确更改,但其他值为空.

所以我需要做的是更新用户名和密码并保留所有剩余的数据.

Answer 1

如果您真的使用PATCH,那么您应该使用RequestMethod.PATCH,而不是RequestMethod.POST.

您的补丁映射应包含用于检索要修补的Manager对象的ID.此外,它应该只包括您要更改的字段.在您的示例中,您正在发送整个实体,因此您无法识别实际更改的字段(空值表示单独保留此字段或实际将其值更改为空).

也许这样的实现就是你所追求的？

@RequestMapping(value = "/manager/{id}", method = RequestMethod.PATCH)
public @ResponseBody void saveManager(@PathVariable Long id, @RequestBody Map<Object, Object> fields) {
    Manager manager = someServiceToLoadManager(id);
    // Map key is field name, v is value
    fields.forEach((k, v) -> {
       // use reflection to get field k on manager and set it to value k
        Field field = ReflectionUtils.findField(Manager.class, k);
        ReflectionUtils.setField(field, manager, v);
    });
    managerService.saveManager(manager);
}

Answer 2

这样，您可以修补更改

1. Autowire `ObjectMapper` in controller;

2. @PatchMapping("/manager/{id}")
    ResponseEntity<?> saveManager(@RequestBody Map<String, String> manager) {
        Manager toBePatchedManager = objectMapper.convertValue(manager, Manager.class);
        managerService.patch(toBePatchedManager);
    }

3. Create new method `patch` in `ManagerService`

4. Autowire `NullAwareBeanUtilsBean` in `ManagerService`

5. public void patch(Manager toBePatched) {
        Optional<Manager> optionalManager = managerRepository.findOne(toBePatched.getId());
        if (optionalManager.isPresent()) {
            Manager fromDb = optionalManager.get();
            // bean utils will copy non null values from toBePatched to fromDb manager.
            beanUtils.copyProperties(fromDb, toBePatched);
            updateManager(fromDb);
        }
    }

您将必须扩展BeanUtilsBean以实现非null值行为的复制。

public class NullAwareBeanUtilsBean extends BeanUtilsBean {

    @Override
    public void copyProperty(Object dest, String name, Object value)
            throws IllegalAccessException, InvocationTargetException {
        if (value == null)
            return;
        super.copyProperty(dest, name, value);
    }
}

最后，将NullAwareBeanUtilsBean标记为 @Component

要么

注册NullAwareBeanUtilsBean为bean

@Bean
public NullAwareBeanUtilsBean nullAwareBeanUtilsBean() {
    return new NullAwareBeanUtilsBean();
}

Answer 3

您可以编写仅更新特定字段的自定义更新查询：

@Override
public void saveManager(Manager manager) {  
    Query query = sessionFactory.getCurrentSession().createQuery("update Manager set username = :username, password = :password where id = :id");
    query.setParameter("username", manager.getUsername());
    query.setParameter("password", manager.getPassword());
    query.setParameter("id", manager.getId());
    query.executeUpdate();
}