GSONを使用してリスト形式のJavaオブジェクトをJSONに変換しようとしています。いくつかの方法を試しましたが、同じエラーが発生します。
最初の試み
List<Techinv> techs = UserUtil.getTechModels(group, org);
Gson gson = new Gson();
String json = gson.toJson(techs);
2回目の試行
List<Techinv> techs = UserUtil.getTechModels(group, org);
Type listType = new TypeToken<List<Techinv>>() {}.getType();
Gson gson = new Gson();
String json = gson.toJson(techs, listType);
3回目の試行
List<Techinv> techs = UserUtil.getTechModels(group, org);
GsonBuilder gsonBuilder = new GsonBuilder();
new GraphAdapterBuilder()
.addType(Techinv.class)
.registerOn(gsonBuilder);
Gson gson = gsonBuilder.create();
String json = gson.toJson(techs);
上記のすべてが失敗し、Javaベクトルへのastackoverflow errorまたはa can't convert java int（私のTechinvクラスのメンバーの1つ）がすべてGSONライブラリにあります。
これらすべての例で単純なものが欠けていることを教えてください:)
Techinvクラス（必要な場合）
package org.cchit.inv.model;
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.Lob;
import javax.persistence.ManyToOne;
import javax.persistence.NamedNativeQueries;
import javax.persistence.NamedNativeQuery;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
/**
* The persistent class for the techinv database table.
*
*/
@Entity
@NamedNativeQueries ({
@NamedNativeQuery(name="Techinv.deleteByOrgId",
query="DELETE FROM techinv where org_id = ?")
})
@NamedQueries ({
@NamedQuery(name="Techinv.removeUser",
query="UPDATE Techinv t SET user_id = 0 where t.id = :techid"),
@NamedQuery(name="Techinv.getAllByOrg",
query="SELECT p FROM Techinv p where p.organization.liferayId = :orgid"),
@NamedQuery(name="Techinv.getById",
query="SELECT t FROM Techinv t where t.id = :id"),
@NamedQuery(name="Techinv.getByProdOrg",
query="SELECT p FROM Techinv p where p.organization.liferayId = :orgid and p.product.id = :prodid"),
@NamedQuery(name="Techinv.delete",
query="DELETE FROM Techinv t where t.id = :id")
})
@Table(name="techinv")
public class Techinv implements Serializable {
private static final long serialVersionUID = 1L;
@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
@Column(name="mu_mask")
private long muMask;
@Column(name="mu_assigned_mask")
private long muAssignedMask;
@Column(name="mu_asked_assign_mask")
private long muAskedAssignedMask;
@Column(name="mu_cert_mask")
private long muWillCertMask;
@Column(name="mu_ask_will_cert_mask")
private long muAskedWillCertMask;
@Column(name="certType")
private String certType;
@Temporal(TemporalType.DATE)
@Column(name="Apply_date")
private Date applyDate;
@Temporal(TemporalType.DATE)
@Column(name="Cert_date")
private Date certDate;
@Lob()
private String notes;
//bi-directional many-to-one association to OrgUser
@ManyToOne
@JoinColumn(name="user_id")
private OrgUser orgUser;
//bi-directional many-to-one association to Organization
@ManyToOne
@JoinColumn(name="org_id")
private Organization organization;
//bi-directional many-to-one association to Product
@ManyToOne
@JoinColumn(name="prod_id")
private Product product;
//bi-directional many-to-one association to Certification
@ManyToOne
@JoinColumn(name="cert_id")
private Certification certification;
public void setCertification(Certification certification) {
this.certification = certification;
}
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
public Techinv() {
}
public int getId() {
return this.id;
}
public void setId(int id) {
this.id = id;
}
public String getNotes() {
return this.notes;
}
public void setNotes(String notes) {
this.notes = notes;
}
public OrgUser getOrgUser() {
return this.orgUser;
}
public void setOrgUser(OrgUser orgUser) {
this.orgUser = orgUser;
}
public Organization getOrganization() {
return this.organization;
}
public void setOrganization(Organization organization) {
this.organization = organization;
}
public long getMuMask() {
return muMask;
}
public void setMuMask(long muMask) {
this.muMask = muMask;
}
public long getMuAssignedMask() {
return muAssignedMask;
}
public void setMuAssignedMask(long muAssigned) {
this.muAssignedMask = muAssigned;
}
public Certification getCertification() {
return certification;
}
public long getMuWillCertMask() {
return muWillCertMask;
}
public void setMuWillCertMask(long muWillCertMask) {
this.muWillCertMask = muWillCertMask;
}
public long getMuAskWillCertMask() {
return muAskedWillCertMask;
}
public void setMuAskedWillCertMask(long muAskedWillCertMask) {
this.muAskedWillCertMask = muAskedWillCertMask;
}
/**
* This will set the question to true. Once asked and answered, this cannot be unset.
* @param mu
*/
public void setMuAskedAssignedMask(Mu mu) {
this.muAskedAssignedMask |= mu.getMask();
}
public boolean isCertified(Mu mu) {
return getCertification() != null && (getCertification().getMuMask() & mu.getMask()) > 0;
}
public boolean isAssigned(Mu mu) {
return (getMuAssignedMask() & mu.getMask()) > 0;
}
public boolean hasAskedToCertify(Mu mu) {
return isAssigned(mu) && !isCertified(mu) && (getMuAskWillCertMask() & mu.getMask()) > 0;
}
public boolean isWillCertify(Mu mu) {
return hasAskedToCertify(mu) && (getMuWillCertMask() & mu.getMask()) > 0;
}
public boolean hasMu(Mu mu) {
return (getMuMask() & mu.getMask()) > 0;
}
public boolean hasAskedToAssign(Mu mu) {
return (muAskedAssignedMask & mu.getMask()) > 0;
}
public String getCertType() {
return certType;
}
public void setCertType(String certType) {
this.certType = certType;
}
public Date getApplyDate() {
return applyDate;
}
public void setApplyDate(Date applyDate) {
this.applyDate = applyDate;
}
public Date getCertDate() {
return certDate;
}
public void setCertDate(Date certDate) {
this.certDate = certDate;
}
}