如何向我的 Spring MVC REST 服务添加错误？

如果用户没有输入我正在编码的两个名称，我如何更改/更新来自 Spring MVC 的以下 REST 调用以返回错误。未找到?

@RequestMapping(value = "/{name}", method = RequestMethod.GET)
@ResponseBody
public User getName(@PathVariable String name, ModelMap model)
{
    logger.debug("I am in the controller and got user name: " + name);

    /*
        Simulate a successful lookup for two users. This
        is where your real lookup code would go.
     */

    if ("name2".equals(name))
    {
        return new User("real name 2", name);
    }

    if ("name1".equals(name))
    {
        return new User("real name 1", name);
    }

    return null;
}

定义一个新的异常类，例如ResourceNotFoundException并从带注释的控制器方法中抛出一个实例getName.

然后还在您的 Controller 类中定义一个带注释的异常处理程序方法来处理该异常，并返回 404 Not Found 状态代码，可能会记录它。

@ExceptionHandler(ResourceNotFoundException.class)
@ResponseStatus(value = HttpStatus.NOT_FOUND)
public void handleResourceNotFoundException(ResourceNotFoundException ex)
{
    LOG.warn("user requested a resource which didn't exist", ex);
}

或者甚至使用 @ResponseBody 注释返回一些错误消息：

@ExceptionHandler(ResourceNotFoundException.class)
@ResponseStatus(value = HttpStatus.NOT_FOUND)
@ResponseBody
public String handleResourceNotFoundException(ResourceNotFoundException ex)
{
    return ex.getMessage();
}