GlassFish 4.0 w / Jersey毫无例外地返回500内部服务器错误
我正在使用GlassFish 4.0服务器和服务器端JPA类，我想通过JAX-RS提供。 到目前为止，这对于简单的实体来说效 但是，如果我有一个@OneToMany关系例如并且存在链接实体，则服务器返回500内部服务器错误。 在这种情况下，服务器日志中不会记录任何内容。 为了找到错误，我创建了一个小的自定义JSP页面，以获取有关所发生事件的更多信息。 代码就是这样：
Status: Throwable: 不幸的是，输出只是“状态：500 Throwable：null”
我自己的服务器端代码似乎运行正常（做了一些调试输出），但是，出现了一些错误。 在此示例中，除非存在链接的IssueComment实体，否则可以毫无问题地检索User和Issue类：
用户类：
package my.application.model; import static javax.persistence.FetchType.LAZY; import java.io.Serializable; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.OneToMany; import javax.persistence.Table; import javax.xml.bind.annotation.XmlRootElement; /** * The persistent class for the User database table. * */ @XmlRootElement @Entity(name="User") @Table(name="User") public class User implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="id") private int id; @Column(name="failedLogin") private short failedLogin; @Column(name="firstname") private String firstname; @Column(name="lastname") private String lastname; @Column(name="middlename") private String middlename; @Column(name="password") private String password; @Column(name="username") private String username; //bi-directional many-to-one association to IssueComment @OneToMany(mappedBy="user", fetch = LAZY) private List issueComments; //bi-directional many-to-one association to SignalComment @OneToMany(mappedBy="user", fetch = LAZY) private List signalComments; //bi-directional many-to-one association to SignalMeasure @OneToMany(mappedBy="user", fetch = LAZY) private List signalMeasures; public User() { } public int getId() { return this.id; } // more getters and setters auto-generated by Eclipse }
用户类：
package my.application.model; import java.io.Serializable; import java.util.Date; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.NamedQuery; import javax.persistence.OneToMany; import javax.persistence.Table; import javax.persistence.Temporal; import javax.persistence.TemporalType; import javax.xml.bind.annotation.XmlRootElement; @NamedQuery( name = "getSingleIssue", query = "SELECT i FROM Issue i WHERE i.id = :id" ) /** * The persistent class for the Issue database table. * */ @XmlRootElement @Entity(name="Issue") @Table(name="Issue") public class Issue implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="id") private int id; @Column(name="concernedModule") private String concernedModule; @Column(name="createdate") @Temporal(TemporalType.TIMESTAMP) private Date createdate; @Column(name="duedate") @Temporal(TemporalType.TIMESTAMP) private Date duedate; @Column(name="priority") private int priority; @Column(name="reminderdate") @Temporal(TemporalType.TIMESTAMP) private Date reminderdate; @Column(name="responsibleUserId") private int responsibleUserId; @Column(name="sendingModule") private String sendingModule; @Column(name="severity") private int severity; @Column(name="status") private int status; @Column(name="title") private String title; // bidirectional many-to-one association to IssueComment @OneToMany(mappedBy = "issue") private List issueComments; public Issue() { } public int getId() { return this.id; } // more getters and setters.... }
IssueComment：
package my.application.model; import java.io.Serializable; import javax.persistence.*; import java.util.Date; /** * The persistent class for the IssueComment database table. * */ @Entity(name="IssueComment") @Table(name="IssueComment") public class IssueComment implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue @Column(name="id") private int id; @Lob @Column(name="comment") private String comment; @Temporal(TemporalType.TIMESTAMP) @Column(name="time") private Date time; //bi-directional many-to-one association to Issue @ManyToOne(fetch = FetchType.EAGER) @JoinColumn(name="issueId") private Issue issue; //bi-directional many-to-one association to User @ManyToOne(fetch = FetchType.EAGER) @JoinColumn(name="userId") private User user; public IssueComment() { } public int getId() { return this.id; } public void setId(int id) { this.id = id; } // getters/setters.... }
Web服务如下：
package my.application.server.webservice; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.QueryParam; import javax.ws.rs.core.MediaType; import javax.ws.rs.ext.Provider; import org.glassfish.jersey.server.ResourceConfig; import my.application.data.UserStorage; import my.application.logger.Logger; import my.application.model.Signal; import my.application.model.SignalComment; import my.application.model.User; @Provider @Path("User") public class UserService extends ResourceConfig { private UserStorage storage = new UserStorage(); public UserService() { this.packages("my.application.model"); } @Produces(MediaType.APPLICATION_XML) @Path("load") @GET public User getUser(@QueryParam("id") int id) { try { Logger.getInstance().log("fetching id: " + id); User u = storage.getUser(id); Logger.getInstance().log("number of signal comments: " + u.getSignalComments().size()); SignalComment sc = u.getSignalComments().get(0); Logger.getInstance().log("Signal 0 comment: " + sc.getComment()); Signal s = sc.getSignal(); Logger.getInstance().log("Signal subject: " + s.getSubject()); return u; } catch (Exception e) { e.printStackTrace(); } // this code is not being reached (so no errors in this method): Logger.getInstance().log("---EXCEPTION HAS BEEN THROWN---"); return null; } }
我放弃了客户端源代码，因为它是服务器端的，可以使用普通的浏览器进行复制，所以没有必要在这里使用客户端代码恕我直言。
确保在您尝试编组为XML的图形（对象）中没有任何循环引用。 例如，这可能会导致问题：
User -> IssueComment -> (the same) User
要么
User -> IssueComment -> Issue -> IssueComment -> (the same) User
这样的结构不能编组成XML。
注意：将@XmlRootElement注释添加到IssueComment （我认为不需要它，但最好将它IssueComment那里）。
注意：我们知道日志记录问题，它将作为JERSEY-2000的一部分解决。