javax.validation.constraints 中的注释不起作用
使用 javax.validation.constraints
中的注解(如 @Size
、@NotNull
等)需要什么配置?这是我的代码:
What configuration is needed to use annotations from javax.validation.constraints
like @Size
, @NotNull
, etc.? Here's my code:
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
public class Person {
@NotNull
private String id;
@Size(max = 3)
private String name;
private int age;
public Person(String id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
}
当我尝试在另一个类中使用它时,验证不起作用(即对象创建时没有错误):
When I try to use it in another class, validation doesn't work (i.e. the object is created without error):
Person P = new Person(null, "Richard3", 8229));
为什么这不对 id
和 name
应用约束?我还需要做什么?
Why doesn't this apply constraints for id
and name
? What else do I need to do?
推荐答案
要让 JSR-303 bean 验证在 Spring 中工作,您需要做几件事:
For JSR-303 bean validation to work in Spring, you need several things:
- 注解的MVC命名空间配置:
<mvc:annotation-driven/>
- JSR-303 规范 JAR:
validation-api-1.0.0.GA.jar
(看起来你已经有了) - 规范的实现,例如 Hibernate Validation,这似乎是最常用的示例:
hibernate-validator-4.1.0.Final.jar
- 在要验证的 bean 中,验证注释,来自规范 JAR 或来自实现 JAR(您已经完成)
- 在您要验证的处理程序中,使用
@Valid
注释您要验证的对象,然后在方法签名中包含一个BindingResult
以捕获错误.
- MVC namespace configuration for annotations:
<mvc:annotation-driven />
- The JSR-303 spec JAR:
validation-api-1.0.0.GA.jar
(looks like you already have that) - An implementation of the spec, such as Hibernate Validation, which appears to be the most commonly used example:
hibernate-validator-4.1.0.Final.jar
- In the bean to be validated, validation annotations, either from the spec JAR or from the implementation JAR (which you have already done)
- In the handler you want to validate, annotate the object you want to validate with
@Valid
, and then include aBindingResult
in the method signature to capture errors.
例子:
@RequestMapping("handler.do")
public String myHandler(@Valid @ModelAttribute("form") SomeFormBean myForm, BindingResult result, Model model) {
if(result.hasErrors()) {
...your error handling...
} else {
...your non-error handling....
}
}
相关文章