Java 如何在 Hibernate 查询中将整数参数设置为空？
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How to set Integer parameter as null in Hibernate query?
提问by Tony
I've got an entity:
我有一个实体：
@Entity
@Table(name = "smsc.security_users")
public class User {
@Id
@Column(name = "id")
private int id;
@Column(name = "username")
private String username;
@Column(name = "password")
private String password;
@Column(name = "enabled")
private int enabled;
@Column(name = "master_id", nullable = true)
private Integer master_id;
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "passwordExpiration")
private Date passwordExpiration;
public String getUsername() {
return username;
}
...
I'm talking about master_id. And this is my DAO method:
我在谈论master_id. 这是我的 DAO 方法：
public void add(String userName, String password, Integer master_id) {
Session session = null;
session = this.sessionFactory.getCurrentSession();
Query query = session
.createSQLQuery(
"INSERT INTO smsc.security_users(id,username,password,enabled,passwordExpiration,master_id) VALUES(smsc.SeqDictID.nextval+1,:userName,:password,1,:passwordExpiration,:master_id)")
.setString("userName", userName)
.setString("password", Sha1.getHash(password))
.setTimestamp("passwordExpiration", DateUtil.getTomorrow())
.setInteger("master_id", master_id);
int updated = query.executeUpdate();
}
Log says:
日志说：
Request processing failed; nested exception is java.lang.NullPointerException
请求处理失败；嵌套异常是 java.lang.NullPointerException
and puts pointer at this line:
并将指针指向这一行：
.setInteger("master_id", master_id);
master_idmust be null sometimes. So how can I set null?
master_id有时必须为空。那么如何设置空值呢？
采纳答案by BatScream
If you check the documentation of the Query class, setInteger() method,
如果您查看 Query 类的文档， setInteger() 方法，
Query setInteger(String name,int val)
It takes a name and a primitive type int, as parameters.
它接受一个名称和一个原始类型 int作为参数。
When you pass a wrapper type Integer, whose value is null, during autoboxing, a null pointer Exception occurs.
当您传递值为 null 的包装类型 Integer 时，在自动装箱期间，会发生空指针异常。
For example:
例如：
Integer x = null;
int y = x; // gives a nullpointer exception.
You could use
你可以用
Query setParameter(String name,
Object val,
Type type);
method to set null values.
设置空值的方法。
See Also:
也可以看看：
回答by Roger
For a null object, specify it as:
对于空对象，将其指定为：
query.setParameter("name", object, StandardBasicTypes.INTEGER);
StandardBasicTypes.INTEGERreplaced Hibernate.INTEGER(etc)
StandardBasicTypes.INTEGER替换Hibernate.INTEGER（等）
