Java 输入字段的验证

在我的应用程序中，我在地址栏中输入三个参数的值，

从货币

，

到货币

，以及

金额

在控制器中。我想检查输入数据的正确性。但是我在测试过程中生成了一个异常，没有进一步的进展 那些我需要一个代码，控制器将检查输入数据的正确性，并根据错误发生的字段，生成第400个错误，该错误的名称为错误填写的字段

我已经试过这个验证了

if(!Currency.getAvailableCurrencies().contains(Currency.getInstance(fromCurrency)))

但如果货币不包含fromCurrency，则生成异常

@RestController
class ExchangeController {

    private static final Logger logger = Logger.getLogger(ExchangeController.class.getName());

    @SuppressWarnings("SpringJavaAutowiredFieldsWarningInspection")
    @Autowired
    @Qualifier("dataService")
    private CurrencyExchangeService currencyExchangeService;

    @SuppressWarnings("SameReturnValue")
    @RequestMapping(value = "/", method = RequestMethod.GET, produces = "application/json")
    public String start() {
        return "input parameters";
    }

    @RequestMapping(value = "/convert", method = RequestMethod.GET, produces = "application/json")
    public ExchangeRateDTO converting(@RequestParam("fromCurrency") String fromCurrency,
                                      @RequestParam("toCurrency") String toCurrency,
                                      @RequestParam("amount") String amount) throws IOException {
        if (!Currency.getAvailableCurrencies().contains(Currency.getInstance(fromCurrency))) {

        }
        BigDecimal convertedAmount = currencyExchangeService.convert(fromCurrency, toCurrency, new BigDecimal(amount));
        return new ExchangeRateDTO(fromCurrency, toCurrency, new BigDecimal(amount), convertedAmount);
    }
}

---

您可以使用Hibernate验证程序验证控制器的

@RequestParam

将此依赖项添加到您的

pom.xml

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.10.Final</version>
</dependency>

然后，您可以将诸如

@NotNull

@Min

@Max

之类的注释添加到您的请求参数中

@RequestMapping(value = "/convert", method = RequestMethod.GET, produces = "application/json")
    public ExchangeRateDTO converting(@RequestParam("fromCurrency") @NotNull @NotBlank @Size(max = 10) String fromCurrency,
                                      @RequestParam("toCurrency") String toCurrency,
                                      @RequestParam("amount") String amount) throws IOException {
        if (!Currency.getAvailableCurrencies().contains(Currency.getInstance(fromCurrency))) {

        }
        BigDecimal convertedAmount = currencyExchangeService.convert(fromCurrency, toCurrency, new BigDecimal(amount));

您还可以根据需要定义自定义注释

---

还有一篇更详细、更精彩的文章

将您的

从货币

和

更改为货币

从

字符串

更改为

货币

和

金额

更改为

大十进制

。Spring将执行转换，如果无法转换，则执行异常。如果你真的想坚持使用

String

（我建议你不要这样做），使用一个表单对象并编写一个

Validator

来进行验证。

@RequestMapping(value = "/convert", method = RequestMethod.GET, produces = "application/json")
    public ExchangeRateDTO converting(@RequestParam("fromCurrency") @NotNull @NotBlank @Size(max = 10) String fromCurrency,
                                      @RequestParam("toCurrency") String toCurrency,
                                      @RequestParam("amount") String amount) throws IOException {
        if (!Currency.getAvailableCurrencies().contains(Currency.getInstance(fromCurrency))) {

        }
        BigDecimal convertedAmount = currencyExchangeService.convert(fromCurrency, toCurrency, new BigDecimal(amount));