java Hibernate验证程序。如何使用@Valid注释？

Question

当把@Valid注释放在方法参数级别时，它的用途是什么

public void (@Valid Person p) { ... }

我创建了一个测试，并将无效对象传递给该方法，但什么也没发生
我希望得到一个例外

Answer 1

其目的是根据定义的约束验证对象

从Hibernate Docs

Performs validation recursively on the associated object. If the object is a collection or an array, the elements are validated recursively. If the object is a map, the value elements are validated recursively.

这可能会有帮助http://www.mkyong.com/spring-mvc/spring-3-mvc-and-jsr303-valid-example/

Answer 2

对象上的@Valid注释是验证框架处理注释对象的指示。当用于方法的参数时，这被称为方法级验证。请注意，方法级验证不是核心规范的一部分，事实上，只有当Bean验证集成到容器类型框架（JSF、CDI、JavaEE）中时，才支持方法级验证。当Bean验证集成到这样一个支持容器中时，发生的事情是，在Bean上调用生命周期方法时，容器会检测方法参数上的JSR 303注释，并触发相关Bean的验证

例如，如果在JAX-RS资源类中有以下方法定义：

@Path("/example")
public class MyExampleResourceImpl {

    @POST
    @Path("/")
    public Response postExample(@Valid final Example example) {
        // ....
    }
}

当调用postExample方法以响应JAX-RS容器处理的请求时，将验证examplebean。将此行为与运行独立Java SE应用程序时发生的情况进行对比：

public class MyMainClass {
    public static void main(final String[] args) {
        final MyMainClass clazz = new MyMainClass();
        clazz.echo(new Example());
    }

    public Example echo(@Valid final Example example) {
        // ...
    }
}

在这种情况下，即使包含了所有JSR303运行时JAR，运行该程序也不会触发Example参数的验证。这是因为没有实现方法级验证的容器可用。附录C中的Bean Validation Specification详细描述了所有这些。为了您的利益，我在下面引用了其中的一些内容：

Proposal for method-level validation

This proposition has not been integrated into the core specification and is not part of it. It remains here for archaeological purposes and will be seriously considered for a future revision of this specification. This proposal is likely to be a bit out of sync with the rest of the specification artifacts.

Note: Bean Validation providers are free to implement this proposal as a specific extension. Such specific extension could for example be accessed via the use of the Validator.unwrap method.

A popular demand was to provide a method and parameter level validation mechanism reusing the constraint descriptions of the specification. This set of APIs is meant to be used by interceptor frameworks such as:

• application frameworks like
  • JSR-299
• component frameworks like Enterprise Java Beans
• aspect based frameworks

These frameworks can call the validation APIs to validate either the parameter list or the returned value of a method when such method is called. More precisely, validation occurs around a method invocation. This extension of the Bean Validation API allows to reuse the core engine as well as the constraint definition and declaration for such method level validations.