JAX-RS使用异常映射器 [英] JAX-RS using exception mappers

问题描述

我已经看到，我可以创建一个 javax.ws.rs.ext.ExceptionMapper 的实现，它将抛出的应用程序异常映射到回复对象。

我创建了一个简单的例子，如果持久化对象时手机长度大于20个字符，则会抛出异常。我期待将异常映射到HTTP 400（错误请求）响应;但是，我收到HTTP 500（内部服务器错误），但有以下异常：

  java.lang.ClassCastException：com。 example.exception.InvalidDataException不能转换为java.lang.Error 
  

我缺少什么？任何建议是非常感谢。

异常映射器：

  @Provider 
 public class InvalidDataMapper实现ExceptionMapper< InvalidDataException> {
 
 @Override 
 public Response toResponse（InvalidDataException arg0）{
 return Response.status（Response.Status.BAD_REQUEST）.build（）; 
} 
 
} 
  

异常类：

  public class InvalidDataException extends Exception {
 
 private static final long serialVersionUID = 1L; 
 
 public InvalidDataException（String message）{
 super（message）; 
} 
 
 ... 
 
} 
  

实体类：

  @Entity 
 @Table（name =PERSON）
 @XmlAccessorType（XmlAccessType.FIELD）
 @XmlRootElement 
 public class Person {
 
 @Id @GeneratedValue（strategy = GenerationType.IDENTITY）
 @Column（name = ID）
 private Long id; 
 
 @Column（name =NAME）
 private String name; 
 
 @Column（name =PHONE）
 private String phone; 
 
 public Long getId（）{
 return id; 
} 
 
 public void setId（Long id）{
 this.id = id; 
} 
 
 public String getName（）{
 return name; 
} 
 
 public void setName（String name）{
 this.name = name; 
} 
 
 public String getPhone（）{
 return phone; 
} 
 
 public void setPhone（String phone）{
 this.phone = phone; 
 
 
 @PrePersist 
 public void validate（）throws InvalidDataException {
 if（phone！= null）{
 if（phone.length（） > 20）{
 throw new InvalidDataException（Phone number too long：+ phone）; 
} 
} 
} 
} 
  

服务

$ b

  @Path（persons /）
 @Produces（MediaType.APPLICATION_XML）
 @Consumes （MediaType.APPLICATION_XML）
 @Stateless 
 public class PersonResource {
 
 @Context 
 private UriInfo uriInfo; 
 
 @PersistenceContext（name =simple）
 private EntityManager em; 
 
 @POST 
 public Response createPerson（JAXBElement< Person> personJaxb）{
 Person person = personJaxb.getValue（）; 
 em.persist（person）; 
 em.flush（）; 
 URI personUri = uriInfo.getAbsolutePathBuilder（）。 
 path（person.getId（）。toString（））。build（）; 
 return Response.created（personUri）.build（）; 
} 
 
} 
  

解决方案

InvalidDataException是否包含在PersistenceException中？也许你可以这样做：

  @Provider 
 public class PersistenceMapper实现ExceptionMapper< PersistenceException> {
 
 @Override 
 public Response toResponse（PersistenceException arg0）{
 if（arg0.getCause（）instanceof InvalidDataException）{
 return Response.status（Response.Status .BAD_REQUEST）.build（）; 
} else {
 ... 
} 
} 
 
} 
  

I have read that I can create an implementation of javax.ws.rs.ext.ExceptionMapper that will map a thrown application exception to a Response object.

I've created a simple example which throws an exception if the phone length is greater than 20 characters when persisting the object. I am expecting the exception to be mapped to an HTTP 400 (Bad Request) response; however, I am receiving an HTTP 500 (Internal Server Error) with the following exception:

java.lang.ClassCastException: com.example.exception.InvalidDataException cannot be cast to java.lang.Error

What am I missing? Any advice is greatly appreciated.

Exception mapper:

@Provider
public class InvalidDataMapper implements ExceptionMapper<InvalidDataException> {

    @Override
    public Response toResponse(InvalidDataException arg0) {
        return Response.status(Response.Status.BAD_REQUEST).build();
    }

}

Exception class:

public class InvalidDataException extends Exception {

    private static final long serialVersionUID = 1L;

    public InvalidDataException(String message) {
        super(message);
    }

    ...

}

Entity class:

@Entity
@Table(name="PERSON")
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement
public class Person {

    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="ID")
    private Long id;

    @Column(name="NAME")
    private String name;

    @Column(name="PHONE")
    private String phone;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }   

    @PrePersist
    public void validate() throws InvalidDataException {
        if (phone != null) {
            if (phone.length() > 20) {
                throw new InvalidDataException("Phone number too long: " + phone);
            }
        }       
    }
}

Service:

@Path("persons/")
@Produces(MediaType.APPLICATION_XML)
@Consumes(MediaType.APPLICATION_XML)
@Stateless
public class PersonResource {

    @Context
    private UriInfo uriInfo;

    @PersistenceContext(name="simple")
    private EntityManager em;

    @POST
    public Response createPerson(JAXBElement<Person> personJaxb) {
        Person person = personJaxb.getValue();
        em.persist(person);
        em.flush();
        URI personUri = uriInfo.getAbsolutePathBuilder().
        path(person.getId().toString()).build();
        return Response.created(personUri).build();  
    }

}

解决方案

Is InvalidDataException getting wrapped in a PersistenceException? Maybe you could do something like the following:

@Provider 
public class PersistenceMapper implements ExceptionMapper<PersistenceException> { 

    @Override 
    public Response toResponse(PersistenceException arg0) { 
        if(arg0.getCause() instanceof InvalidDataException) {
           return Response.status(Response.Status.BAD_REQUEST).build(); 
        } else {
           ...
        }
    } 

} 

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