hibernate多表连接 查询的解决方案

大家在用hibernate的时候总会遇到多表连接的查询，遇到这种问题 总是各种纠结。

方案1：建立视图 ，事先在数据库里面建立视图。然后建立这个视图的实体类，指定一个主键。然后建立这个视图的查询.

方案2：给实体类加临时属性HQL查询补充。

上代码：

实体类：

@Entity
@Table(name = "FLOW_RU_INFO")
public class FlowRuInfo implements java.io.Serializable {

// Fields

private String id;
private String deptid;
private String processinstanceid;
private String content;
private String creator;
private Date createtime;
private String flowtype;
private String flowcode;
private String formid;
private String state;
private String currentuserid;
private String pflowtype;
private String formNo;

//临时属性
private String task;
private String lastAudiUser;
private String nextUser;
private String userName;
private String deptName;


// Constructors

/** default constructor */
public FlowRuInfo() {
}



public FlowRuInfo(String id, String deptid, String processinstanceid,
String content, String creator, Date createtime, String flowtype,
String flowcode, String formid, String state, String currentuserid,
String pflowtype, String formNo, String task, String lastAudiUser,
String nextUser, String userName, String deptName) {
super();
this.id = id;
this.deptid = deptid;
this.processinstanceid = processinstanceid;
this.content = content;
this.creator = creator;
this.createtime = createtime;
this.flowtype = flowtype;
this.flowcode = flowcode;
this.formid = formid;
this.state = state;
this.currentuserid = currentuserid;
this.pflowtype = pflowtype;
this.formNo = formNo;
this.task = task;
this.lastAudiUser = lastAudiUser;
this.nextUser = nextUser;
this.userName = userName;
this.deptName = deptName;
}



// Property accessors
@GenericGenerator(name = "generator", strategy = "uuid.hex")
@Id
@GeneratedValue(generator = "generator")
@Column(name = "ID", unique = true, nullable = false, length = 32)
public String getId() {
return this.id;
}

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

@Column(name = "DEPTID", length = 32)
public String getDeptid() {
return this.deptid;
}

public void setDeptid(String deptid) {
this.deptid = deptid;
}

@Column(name = "PROCESSINSTANCEID", length = 100)
public String getProcessinstanceid() {
return this.processinstanceid;
}

public void setProcessinstanceid(String processinstanceid) {
this.processinstanceid = processinstanceid;
}

@Column(name = "CONTENT", length = 800)
public String getContent() {
return this.content;
}

public void setContent(String content) {
this.content = content;
}

@Column(name = "CREATOR", length = 32)
public String getCreator() {
return this.creator;
}

public void setCreator(String creator) {
this.creator = creator;
}


@Column(name = "CREATETIME", length = 7)
public Date getCreatetime() {
return this.createtime;
}

public void setCreatetime(Date createtime) {
this.createtime = createtime;
}

@Column(name = "FLOWTYPE", length = 32)
public String getFlowtype() {
return this.flowtype;
}

public void setFlowtype(String flowtype) {
this.flowtype = flowtype;
}

@Column(name = "FLOWCODE", length = 32)
public String getFlowcode() {
return this.flowcode;
}

public void setFlowcode(String flowcode) {
this.flowcode = flowcode;
}

@Column(name = "FORMID", length = 32)
public String getFormid() {
return this.formid;
}

public void setFormid(String formid) {
this.formid = formid;
}

@Column(name = "STATE", length = 1)
public String getState() {
return this.state;
}

public void setState(String state) {
this.state = state;
}

@Column(name = "CURRENTUSERID", length = 32)
public String getCurrentuserid() {
return this.currentuserid;
}

public void setCurrentuserid(String currentuserid) {
this.currentuserid = currentuserid;
}

@Column(name = "PFLOWTYPE", length = 32)
public String getPflowtype() {
return this.pflowtype;
}

public void setPflowtype(String pflowtype) {
this.pflowtype = pflowtype;
}


@Column(name = "FORM_NO", length = 32)
public String getFormNo() {
return formNo;
}

public void setFormNo(String formNo) {
this.formNo = formNo;
}

@Transient //这种是临时属性的注解
public String getTask() {
return task;
}

public void setTask(String task) {
this.task = task;
}

@Transient
public String getLastAudiUser() {
return lastAudiUser;
}

public void setLastAudiUser(String lastAudiUser) {
this.lastAudiUser = lastAudiUser;
}
@Transient
public String getNextUser() {
return nextUser;
}

public void setNextUser(String nextUser) {
this.nextUser = nextUser;
}
@Transient
public String getUserName() {
return userName;
}

public void setUserName(String userName) {
this.userName = userName;
}
@Transient
public String getDeptName() {
return deptName;
}

public void setDeptName(String deptName) {
this.deptName = deptName;
}

}

HQL查询语句：

//hql多表连接 拼装实体
String hql="select new com.entity.flow.FlowRuInfo(t.id,t.deptid,t.processinstanceid,"
+"t.content, t.creator, t.createtime, t.flowtype,"
+"t.flowcode, t.formid, t.state, t.currentuserid,"
+"t.pflowtype, t.formNo, t.creator, t.creator,"
+"t.creator, u.empName, d.depName) from FlowRuInfo t,Department d,User u where t.creator=u.userid and d.depId=t.deptid order by t.createtime desc";