这里我有一个名为receipt的表，其主键是一个复合键，与其他类Receipt_compoundKey一起引用，其中包含两个名为voucher_id和company_id的变量，
如何使用company_id=1;
@Entity
@Table(name = AMAM_Constants.tb_name.RECEIPT_FROM, catalog = AMAM_Constants.db_name)
public class Receipt implements Serializable {
@Id
private Receipt_CompoundKey id;
@OneToOne
@JoinColumn(name = "FROM_LEDGER")
private Ledger fromLedger;
@Column(name = "VOU_DATE")
private Date voucher_Date;
@Column(name = "TOTAL_AMOUNT")
private double total_amount;
@Column(name = "ACTIVE")
private char active;
@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@JoinTable(name = AMAM_Constants.tb_name.RECEIPT_FROM_LINK_TO, joinColumns = {
@JoinColumn(name = "COMPANY_ID"),
@JoinColumn(name = "VOUCHER_ID")
}, inverseJoinColumns = {
@JoinColumn(name = "RECP_TO")})
private List<Receipt_To> recptToList = new ArrayList<Receipt_To>();
@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinTable(name = AMAM_Constants.tb_name.RECEIPT_FROM_LINK_ADJMTS, joinColumns = {
@JoinColumn(name = "COMPANY_ID"),
@JoinColumn(name = "VOUCHER_ID")
}, inverseJoinColumns = {
@JoinColumn(name = "RECPT_ADJS")})
private List<Receipt_Adj> recptAdjments = new ArrayList<Receipt_Adj>();
public List<Receipt_Adj> getRecptAdjments() {
return recptAdjments;
}
public void setRecptAdjments(List<Receipt_Adj> recptAdjments) {
this.recptAdjments = recptAdjments;
}
public List<Receipt_To> getRecptToList() {
return recptToList;
}
public void setRecptToList(List<Receipt_To> recptToList) {
this.recptToList = recptToList;
}
public char getActive() {
return active;
}
public void setActive(char active) {
this.active = active;
}
public double getTotal_amount() {
return total_amount;
}
public void setTotal_amount(double total_amount) {
this.total_amount = total_amount;
}
public Ledger getFromLedger() {
return fromLedger;
}
public void setFromLedger(Ledger fromLedger) {
this.fromLedger = fromLedger;
}
public Receipt_CompoundKey getId() {
return id;
}
public void setId(Receipt_CompoundKey id) {
this.id = id;
}
public Date getVoucher_Date() {
return voucher_Date;
}
public void setVoucher_Date(Date voucher_Date) {
this.voucher_Date = voucher_Date;
}
}
@Embeddable
public class Receipt_CompoundKey implements Serializable {
@Column(name = "VOUCHER_ID")
private long voucher_Id;
@Column(name = "COMPANY_ID")
private long company_Id;
public Receipt_CompoundKey() {
}
public Receipt_CompoundKey(long voucher_Id) {
this.voucher_Id = voucher_Id;
}
public Receipt_CompoundKey(long voucher_Id, long company_Id) {
this.company_Id = company_Id;
this.voucher_Id = voucher_Id;
}
public long getCompany_Id() {
return company_Id;
}
public void setCompany_Id(long company_Id) {
this.company_Id = company_Id;
}
public long getVoucher_Id() {
return voucher_Id;
}
public void setVoucher_Id(long voucher_Id) {
this.voucher_Id = voucher_Id;
}
}
String query = "from Receipt where active='Y' and id=:id ";
begin();
objList = getSession().createQuery(query).setLong("id", key.getCompany_Id()).setLong("id", key.getVoucher_Id()).list();
commit();
答案 0 :(得分：1)
您可以像使用单列ID一样执行此操作：
getSession().createQuery(query).setParameter("id", key);
您也可以查询密钥的各个值，但这里不需要：
String query = "select r from Receipt r where r.active = 'Y'"
+ " and id.company_Id = :companyId"
+ " and id.voucher_Id = :voucherId";
objList = getSession().createQuery(query)
.setLong("companyId", key.getCompany_Id())
.setLong("voucherId", key.getVoucher_Id())
.list();
请注意，尊重Java命名约定：voucherId而不是voucher_Id，ReceiptCompoundKey而不是Receipt_CompoundKey等。
答案 1 :(得分：1)
首先你必须做一个select而不仅仅是"from Receipt where active='Y' and id=:id "（我认为这是一个不可思议的错误，但万一它不是）：
String query = "
SELECT receipt
FROM Receipt receipt
WHERE receipt.id = :yourId "
为了创建查询，我使用EntityManager。这是一个示例类以及它如何为我工作。
public class EntityManagerUtil {
private static EntityManagerFactory entityManagerFactory = null;
private static final ThreadLocal<EntityManager> entitymanager =
new ThreadLocal<EntityManager>();
private static final ThreadLocal<Map<Class<?>, Set<Serializable>>>collectionFieldNameValues =
new ThreadLocal<Map<Class<?>, Set<Serializable>>>();
public static EntityManagerFactory initializeEntityManagerFactory( String persistenceUnit ) {
if ( entityManagerFactory == null ) {
entityManagerFactory = Persistence.createEntityManagerFactory( persistenceUnit );
}
return entityManagerFactory;
}
public static EntityManager getEntityManager() {
EntityManager entityManager = entitymanager.get();
// Create a new EntityManager
if ( entityManager == null || !entityManager.isOpen()) {
entityManager = entityManagerFactory.createEntityManager();
entitymanager.set( entityManager );
}
return entityManager;
}
public static void close() {
final EntityManager entityManager = entitymanager.get();
entitymanager.set( null );
if ( entityManager != null && entityManager.isOpen()) {
entityManager.close();
}
if ( entityManagerFactory != null && entityManagerFactory.isOpen()) {
entityManagerFactory.close();
}
}
}
在您的类中，您希望获取数据，首先使用持久性单元初始化EntityManagerFactory（以免它称为ReceiptPersistence）。这是它的样子：
EntityManagerUtil.initializeEntityManagerFactory("ReceiptPersistence");
EntityManagerUtil.getEntityManager().getTransaction().begin();
Query getReceiptWithId = EntityManagerUtil.getEntityManager().createQuery(query);
getReceiptWithId.setParameter("yourId", idThatYouWant);
现在，当您的查询准备就绪时，您可以使用getSingleResult（）从中获取单个结果：
Receipt receipt = (Receipt) getReceiptWithId.getSingleResult();
EntityManagerUtil.getEntityManager().getTransaction().commit();
EntityManagerUtil.getEntityManager().close();
如果您这样做是try / catch（推荐），您可以执行EntityManagerUtil.getEntityManager().getTransaction().rollback();当您对数据库进行一些更改时需要它。
我使用ThreadLocal确保每个用户都有1个线程。