2

私は次のようなクラスを持っています：

@Entity
public class Car {


    @Id
    @GeneratedValue
    private Long id;

    @NotNull
    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "OWNER_ID")       
    private Owner owner;

    @NotNull()
    @Column(nullable = false)
    private String make;

    @NotNull() 
    @Column(nullable = true)
    private String model;


    @Column(nullable = false)
    private String gears;

    // More fields

オブジェクトを永続化しようとしているとしましょう。たとえば、フィールドを作成するなどの1つのフィールドがnullであり、これは想定されていません。次の例外がスローされます。

WARNING: EJB5184:A system exception occurred during an invocation on EJB CarEJB, method: public se.while_se.domain.Car se.while_se.business.CarEJB.createCar(se.while_se.domain.Car)
Sep 09, 2012 12:37:37 PM com.sun.ejb.containers.BaseContainer postInvoke
WARNING: 
javax.ejb.EJBException
        at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5215)
        at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5113)
        at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4901)
        at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2045)
        at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1994)
        at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:222)
        at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:88)
        at $Proxy137.createCar(Unknown Source)
        at se.while_se.business.__EJB31_Generated__CarEJB__Intf____Bean__.createCar(Unknown Source)
        at test.CarTest.populate(CarTest.java:197)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
        at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
        at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
        at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
        at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
        at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:45)
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:123)
        at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:104)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:164)
        at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:110)
        at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:175)
        at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcessWhenForked(SurefireStarter.java:107)
        at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:68)
Caused by: javax.validation.ConstraintViolationException: Bean Validation constraint(s) violated while executing Automatic Bean Validation on callback event:'prePersist'. Please refer to embedded ConstraintViolations for details.

私がやりたいのは、データベースに永続化する前にエンティティを検証するためのベストプラクティスを見つけることです。確かに、エンティティクラス内に次のようなヘルプメソッドを実装できます。

public boolean validate() {
        if(owner == null) {            
            return false;
        }
        if(make == null) {
            return false;
        }
        if(model == null) {
            return false;
        } 
        return true;
    }

しかし、それは正しいアプローチとは思えません。案内してもらえますか？

よろしくお願いします

4

1 に答える 1

10

このように永続化する前にエンティティを検証し、適切なエラーを返すことができます。

Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
Set<ConstraintViolation<Car>> constraintViolations = validator.validate(myCar);

if (constraintViolations.size() > 0) {
    Set<String> violationMessages = new HashSet<String>();

    for (ConstraintViolation<T> constraintViolation : constraintViolations) {
        violationMessages.add(constraintViolation.getPropertyPath() + ": " + constraintViolation.getMessage());
    }

    throw new RuntimeException("Car is not valid:\n" + StringUtils.join(violationMessages, "\n"));
}
于 2012-09-09T12:23:43.093 に答える