jpa集合元素的映射

package com.demo.beans;


import java.util.Date;


import javax.persistence.Column;
import javax.persistence.Embeddable;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;


@Embeddable
public class EmployeePeriod {
 @Column(name="EmployeeStartDate")
 @Temporal(TemporalType.DATE)
 private Date startDate;


@Column(name="EmployeeEndDate")
 @Temporal(TemporalType.DATE)
 private Date endDate;


public Date getStartDate() {
 return startDate;
 }
 public void setStartDate(Date startDate) {
 this.startDate = startDate;
 }
 public Date getEndDate() {
 return endDate;
 }
 public void setEndDate(Date endDate) {
 this.endDate = endDate;
 }

}

package com.demo.beans;


import java.util.Collection;
import java.util.Set;


import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.EntityListeners;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;




@Entity
@EntityListeners(MyMonitor.class)
public class Employee {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
 private int id;




 private String employeeName;


 @ElementCollection(targetClass = EmployeePeriod.class)
 private Collection employeePeriod;
 @ElementCollection
 private Set<String> nickName;
 


public Collection getEmployeePeriod() {
    return employeePeriod;
}


public void setEmployeePeriod(Collection employeePeriod) {
    this.employeePeriod = employeePeriod;
}


public Set<String> getNickName() {
    return nickName;
}


public void setNickName(Set<String> nickName) {
    this.nickName = nickName;
}


public String getEmployeeName() {
 return employeeName;
 }


public int getId() {
    return id;
}


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


public void setEmployeeName(String employeeName) {
 this.employeeName = employeeName;
 }

}

创建employee对象

// Create an Employee Period Instance
        EmployeePeriod period = new EmployeePeriod();
        period.setStartDate(new Date());
        period.setEndDate(new Date());
        
        List<EmployeePeriod> lists = new LinkedList<EmployeePeriod>();
        lists.add(period);
        Set<String> sets = new HashSet<String>();
        sets.add("bai");
        sets.add("xiaoyu");
        employee.setNickName(sets);
        employee.setEmployeePeriod(lists);
     //  employee.setEmployeePeriod(period);
        userRepository.addEmployee(employee);

保存后的数据库表信息如下：

mysql> select * from employee;
+----+--------------+------------+------------+
| id | employeeName | end        | begin      |
+----+--------------+------------+------------+|
|  1 | John Smith   | NULL       | NULL       |
+----+--------------+------------+------------+

mysql> select * from employee_nickname;
+-------------+----------+
| Employee_id | nickName |
+-------------+----------+
|           4 | bai      |
|           4 | xiaoyu   |
+-------------+----------+

mysql> select * from employee_employeeperiod;
+-------------+-----------------+-------------------+
| Employee_id | EmployeeEndDate | EmployeeStartDate |
+-------------+-----------------+-------------------+
|           3 | 2015-02-13      | 2015-02-13        |
|           4 | 2015-02-13      | 2015-02-13        |
+-------------+-----------------+-------------------+

mysql> select * from TABLE_CONSTRAINTS where table_schema='test';
+--------------------+-------------------+------------------------------+--------------+-------------------------+-----------------+
| CONSTRAINT_CATALOG | CONSTRAINT_SCHEMA | CONSTRAINT_NAME              | TABLE_SCHEMA | TABLE_NAME              | CONSTRAINT_TYPE |
+--------------------+-------------------+------------------------------+--------------+-------------------------+-----------------+
| def                | test              | PRIMARY                      | test         | employee                | PRIMARY KEY     |
| def                | test              | FK_1pxsqqta9epq8xd7ht1st8yxf | test         | employee_employeeperiod | FOREIGN KEY     |
| def                | test              | FK_f3slu53dbxkjrr7uejqhoxgf4 | test         | employee_nickname       | FOREIGN KEY     |

可以使用@CollectionTable指定集合表名字@AtriibulteOverride来自定义列的名字