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在代码中，想让数据库中的一个字段在无数据插入时使用默认值
持久类代码如下
@Entity@Table(name = "dormitory")@DynamicInsert(true)@DynamicUpdate(true)public class Dormitory implements Serializable{ private int ID; private String adress; private Set students = new HashSet<>(); private int number; public Dormitory() { } public Dormitory(String adress, int number) { this.adress = adress; this.number = number; } public Dormitory(String adress) { this.adress = adress; } @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Basic public int getID() { return ID; } public void setID(int ID) { this.ID = ID; } @Column(name = "adress",nullable = false,length = 20) @Basic public String getAdress() { return adress; } public void setAdress(String adress) { this.adress = adress; } @OneToMany @JoinColumn(name = "dormitory_id") public Set getStudents() { return students; } public void setStudents(Set students) { this.students = students; } @Column(name = "number",columnDefinition = "INT default 4") @Basic public int getNumber() { return number; } public void setNumber(int number) { this.number = number; }} 测试类如下 public class StuTest { @Test public void hello(){ Dormitory dormitory = new Dormitory("6#522"); DormitoryDao dormitoryDao = new DormitoryDao(HibernateUtils.getSessionFactory()); dormitoryDao.insertDormitory(dormitory); dormitoryDao.commit(); }} 输出的语句为 insert into dormitory (adress, number) values (?, ?)这是因为持久化类中number属性用的是int，int未赋值时默认0，解决办法很简单，吧它改成Integer 修改后的持久化类
@Entity@Table(name = "dormitory")@DynamicInsert(true)@DynamicUpdate(true)public class Dormitory implements Serializable{ private int ID; private String adress; private Set students = new HashSet<>(); private Integer number; public Dormitory() { } public Dormitory(String adress, Integer number) { this.adress = adress; this.number = number; } public Dormitory(String adress) { this.adress = adress; } @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Basic public int getID() { return ID; } public void setID(int ID) { this.ID = ID; } @Column(name = "adress",nullable = false,length = 20) @Basic public String getAdress() { return adress; } public void setAdress(String adress) { this.adress = adress; } @OneToMany @JoinColumn(name = "dormitory_id") public Set getStudents() { return students; } public void setStudents(Set students) { this.students = students; } @Column(name = "number",columnDefinition = "INT default 4") @Basic public Integer getNumber() { return number; } public void setNumber(Integer number) { this.number = number; }} 依然使用上个测试 hibernate输出的SQL为 insert into dormitory (adress) values (?)Integer是类，所以默认是null
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