JPA中的集合查询示例
１、VisitInfo模型view plaincopy to clipboardprint?
@Entity
@Table(name = "System_VisitInfo")
@Cache(usage=CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class VisitInfo implements Serializable {
private static final long serialVersionUID = 2877662856939429897L;
@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private Long id;
private Date vdate;
@Column(length = 200)
private String fromUrl;
@Column(length = 200)
private String url;
@Column(length = 50)
private String ip;
private Integer status;
@Column(length=1000)
private String remark;
@ManyToMany
private List<SystemVisitDir> dirs=new java.util.ArrayList<SystemVisitDir>();
public Long getId() {
return id;
}
//setter及getter
}
@Entity
@Table(name = "System_VisitInfo")
@Cache(usage=CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class VisitInfo implements Serializable {
private static final long serialVersionUID = 2877662856939429897L;
@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private Long id;
private Date vdate;
@Column(length = 200)
private String fromUrl;
@Column(length = 200)
private String url;
@Column(length = 50)
private String ip;
private Integer status;
@Column(length=1000)
private String remark;
@ManyToMany
private List<SystemVisitDir> dirs=new java.util.ArrayList<SystemVisitDir>();
public Long getId() {
return id;
}
//setter及getter
}view plaincopy to clipboardprint?
<STRONG>２、SystemVisitDir 模型</STRONG>
２、SystemVisitDir 模型view plaincopy to clipboardprint?
<PRE class=java name="code">
@Entity
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
@FormPO(inject = "title,url,parent,sequence")
public class SystemVisitDir implements Serializable, IJsonObject {
private static final long serialVersionUID = -6636698603262819988L;
@Id
@javax.persistence.GeneratedValue(strategy = javax.persistence.GenerationType.TABLE)
private Long id;
@Column(length = 20)
@Field(validators = { @Validator(name = "string", value = "blank;min:2;max:20", required = true) })
private String title;// 栏目名称
@Column(length =500)
@Field(validators = { @Validator(name = "url", required = true) })
private String url;// 栏目url
private Long num = 0l;// 访问量
private Date lastVisitTime;// 最后一次访问时间
private Integer sequence = 1;// 排序
@javax.persistence.ManyToOne(fetch = FetchType.EAGER)
@POLoad(name = "parentId")
private SystemVisitDir parent;// 父级目录
private Integer status = 0;
@OneToMany(mappedBy = "parent")
@OrderBy("sequence")
private List<SystemVisitDir> children = new java.util.ArrayList<SystemVisitDir>();// 子目录
//getter及setter
}
</PRE>
view plaincopy to clipboardprint?@Entity @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
@FormPO(inject = "title,url,parent,sequence")
public class SystemVisitDir implements Serializable, IJsonObject
{
private static final long serialVersionUID = -6636698603262819988L;
@Id
@javax.persistence.GeneratedValue(strategy = javax.persistence.GenerationType.TABLE)
private Long id;
@Column(length = 20)
@Field(validators = { @Validator(name = "string", value = "blank;min:2;max:20", required = true) })
private String title;// 栏目名称
@Column(length =500)
@Field(validators = { @Validator(name = "url", required = true) })
private String url;// 栏目url
private Long num = 0l;// 访问量
private Date lastVisitTime;// 最后一次访问时间
private Integer sequence = 1;// 排序
@javax.persistence.ManyToOne(fetch = FetchType.EAGER)
@POLoad(name = "parentId")
private SystemVisitDir parent;// 父级目录
private Integer status = 0;
@OneToMany(mappedBy = "parent")
@OrderBy("sequence")
private List<SystemVisitDir> children = new java.util.ArrayList<SystemVisitDir>();// 子目录
//getter及setter
}
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@Entity
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
@FormPO(inject = "title,url,parent,sequence")
public class SystemVisitDir implements Serializable, IJsonObject {
private static final long serialVersionUID = -6636698603262819988L;
@Id
@javax.persistence.GeneratedValue(strategy = javax.persistence.GenerationType.TABLE)
private Long id;
@Column(length = 20)
@Field(validators = { @Validator(name = "string", value = "blank;min:2;max:20", required = true) })
private String title;// 栏目名称
@Column(length =500)
@Field(validators = { @Validator(name = "url", required = true) })
private String url;// 栏目url
private Long num = 0l;// 访问量
private Date lastVisitTime;// 最后一次访问时间
private Integer sequence = 1;// 排序
@javax.persistence.ManyToOne(fetch = FetchType.EAGER)
@POLoad(name = "parentId")
private SystemVisitDir parent;// 父级目录
private Integer status = 0;
@OneToMany(mappedBy = "parent")
@OrderBy("sequence")
private List<SystemVisitDir> children = new java.util.ArrayList<SystemVisitDir>();// 子目录
//getter及setter
}
３、集合查询
集合查询主要涉及到一些关键字，主要是EMPTY及MEMBER OF。下面的例子查询某一个目录里面的VisitInfo
public Page doListVisit(WebForm form, Module module)
{
QueryObject qo = form.toPo(QueryObject.class);
String id = CommUtil.null2String(form.get("parentId"));
if (!"".equals(id))
{
SystemVisitDir parent = this.service.getVisitDir(new Long(id));
qo.addQuery("(?MEMBER OF obj.dirs)",new Object[]{parent});
}
IPageList pageList = service.queryVisistInfo(qo);
form.jsonResult(pageList); return Page.JSONPage;
}
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