Java导出为XML不能工作

Question

我一直在使用教程来获得我的对象导出为XML…我看到下面的错误与下面的对象。我不知道出了什么问题....首先，我得到了关于id和name元素被注释掉的错误，然后是关于根元素的错误。

    Mapped exception to response: 500 (Internal Server Error) javax.ws.rs.WebApplicationException: 
   com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions java.sql.Date does not have a no-arg default constructor.
this problem is related to the following location: at java.sql.Date at private java.sql.Date contentmanagement.Guest.signingDate at contentmanagement.Guest at com.sun.jersey.core.provider.jaxb.AbstractRootElementProvider.writeTo(AbstractRootElementProvider.java:159) at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:306) at.....

好像是我的约会对象。

package contentmanagement;
import java.io.Serializable;
import java.sql.Date;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@Entity
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Guest implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name;
    private Date signingDate;
    public Guest() {
    }
    public Guest(String name) {
        this.name = name;
        this.signingDate = new Date(System.currentTimeMillis());
    }
    //@XmlElement(name = "id")
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    //@XmlElement(name = "name")
    public String getName() {
        return name;
    }
    @Override
    public int hashCode() {
        int hash = 0;
        hash += (id != null ? id.hashCode() : 0);
        return hash;
    }
    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof Guest)) {
            return false;
        }
        Guest other = (Guest) object;
        if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
            return false;
        }
        return true;
    }
    @Override
    public String toString() {
        return name + " (signed on " + signingDate + ")";
    }
}

旁注:有没有更好的方式来查看日志?比在显示堆栈跟踪的实字符串中?有什么特别的应用程序吗?目前我正在查看我的日志:http://localhost:4848/common/index.jsf

控制器抛出的错误是:

@GET @Path("getGuestsXml")
@Produces("application/xml")
public Guest getGuestsXml() {
    Guest response = new Guest();
    //response.setId(9L);
    return response;
}

Answer 1

看起来java.sql.Date是麻烦制造者，因为它没有零参数构造函数。您可能需要为它编写一个序列化器/适配器。

在这里找到更多，希望能有所帮助:

jaxb unmarshal timestamp

如何序列化java.sql.Date为长，当使用web服务?

就日志/堆栈跟踪而言:您更喜欢其他视图吗?从开发人员的角度来看，详细的堆栈跟踪很好。对于您系统的用户，您永远不希望显示这些错误，因此请确保捕获这些错误并显示一个温和的错误页面。