HQL中cast的使用

[cuizhiyong]

HQL中如何实现把string类型转换成float？

[handong890]

Float.valueOf(str)
这样转啊
比如HQL
String sql = "form xxx where i > " + Float.valueOf(str)
+ "";

[cuizhiyong]

楼上的你试过了吗？
java.lang.IllegalStateException: No data type for node: org.hibernate.hql.ast.tree.MethodNode 错误

[cuizhiyong]

hibernate 官方文档中说使用cast，但我试了试也不行

[handong890]

数据库SQL2000
表 testfloat
字段 类型
id varchar
num float

vo
public class Testfloat implements java.io.Serializable {


// Fields

private String id;
private Float num;


// Constructors

/** default constructor */
public Testfloat() {
}


/** full constructor */
public Testfloat(Float num) {
this.num = num;
}


// Property accessors

public String getId() {
return this.id;
}

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

public Float getNum() {
return this.num;
}

public void setNum(Float num) {
this.num = num;
}

}


DAO

public List test(String a)
{
float f = Float.valueOf(a);
List list = null;
String sql = "from Testfloat where num > "+f+" ";
System.out.println(sql);
Query query = getSession().createQuery(sql);
list = query.list();
return list;
}

main 方法

TestfloatDAO tdao = new TestfloatDAO();
List list2 = null;
list2 =tdao.test("1.7");
System.out.println("查到" + list2.size());

hbm.xml
<hibernate-mapping>
<class name="com.mybbs.DAO.Testfloat" table="testfloat" schema="dbo" catalog="BBS">
<id name="id" type="java.lang.String">
<column name="id" length="50" />
<generator class="uuid.hex" />
</id>
<property name="num" type="java.lang.Float">
<column name="num" precision="53" scale="0" />
</property>
</class>
</hibernate-mapping>


运行正确可以正常查询

[cchaha]

传float的封装类对象实例,类似下面:

String s="123";
Float f=new Float(s);
Query query=session.createQuery("from User user where user.s:s");
query.setParameter("s",s);