How to handle compound key with relationship in JPA2 and Spring Data JPA? - jpa

Question

I have a problem to handle mapping object relationship for mysql tables.
I have 2 tables shown below:
Device
-----------
deviceId PK
deviceName
ApkInfo
--------
id PK
packageName
appName
deviceId FK
And then here are my classes:
#Entity
#Table(name="Device")
public class Device implements Serializable {
#Column
#Id
private String deviceId;
#Column
private String deviceName;
//getters and setters
}
#Entity
#Table(name="ApkInfos")
public class ApkInfo implements Serializable {
#Column
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private int id;
#Column
#Id
private String packageName;
#Column
private String appName;
#Column
#Temporal(TemporalType.TIMSTAMP)
private Date installDate;
#ManyToOne
#JoinColumn(name="deviceId" referencedColumnName="deviceId")
private Device device;
//getters and setters
}
This works for me, but I want to use compound key, deviceId and packageName, in ApkInfos table.
#Entity
#Table(name="ApkInfos")
public class ApkInfo implements Serializable {
#Colum(instable=false, updatable=false)
#Id
private String deviceId;
#Column
private String packageName;
#Column
private String appName;
#ManyToOne
#JoinColumn(name="deviceId" referencedColumnName="deviceId")
private Device device;
//getters and setters
}
But when I tried to save an entity using Spring Data JPA repository, I got an error:
org.springframework.dao.InvalidAccessApiUsageException: Class must not
be null, nested exception is java.lang.IllegalArgumentException: Class
must not be null
ApkInfo apkInfo = new ApkInfo();
apkInfo.setDeviceId("1234");
apkInfo.setPackageName("aaa");
apkInfo.setAppName("myapp");
apkInfo.setInstallDate(new Date());
apkInfo.setDevice(new Device("1234"));
repository.save(apkInfo);
And device has the deviceID '1234' already exists in the Device table.

Answer 1

I created a separate primary key class added #IdClass in the ApkInfo class. It works fine now, thanks. I am going to have a look at EmbeddedId more later.
I added #IdClass at the entity class and #Id for the packageName property. Also I made insert, update false for the One-to-many column.
#Entity
#Table(name="ApkInfos")
#IdClass(ApkInfo.class)
public class ApkInfo implements Serializable {
#Column #Id private String deviceId;
#Column #Id private String packageName;
#ManyToOne
#JoinColumn(name="deviceId" referencedColumnName="deviceId", insetable=false, updatable=false)
private Device device;
//getters and setters missing
}
Primary key class has only setters and overrides equals and hasCode methods.
public class ApkInfo implements Serializable {
private String deviceId;
private String packageName;
public ApkInfo(){}
public ApkInfo (String deviceId, String packageName){
this.deviceId = deviceId;
this.packageName = packageName;
}
public String getDeviceId(){
return this.deviceId;
}
public String getPackageName(){
return this.packageName;
}
#Override
public boolean equals(Object obj){
return (obj!=null &&
obj instanceof ApkInfoPk &&
deviceId.equals(((ApkInfoPk)obj).getDeviceId()) &&
packageNames.equals(((ApkInfoPk)obj).getPackageName()) );
}
#Override
public int hashCode(){
super.hashCode();
}
}