Grails 将字段调整为存储到数据库

假设我有一个字段

content

，它是json。我想将其存储在数据库中，以便我的域类只保留1字段。（这更像是一项脑力劳动；-）

我希望我的域对象只公开

内容

，因此我不想使用另一个字段，如

字符串contentAsText

，因为它在外部可见

在整个GORM文档中，我还没有找到如何管理它的方法。我尝试了

beforeValidate（）/beforeinstert（）

和

onLoad（）

方法，但没有成功

如何在值持久化之前调整它

class MyDomain{

   JSONElement content

   static constraints = {
        content nullable: false, blank: false, sqlType: "text" // adapter from Map to String??
    }

    def setContent(String textContent){
        content = JSON.parse(textContent)
    }
}

我必须做两件事

将

def content

替换为

JSON content

，使其持久化，请参阅

通过

def setContent（）

将json字符串转换回json

---

由于

content

是

JSONElement

使用

JSONObject

和

JSONArray

作为具体类。

您可以为

JSONElement

定义自定义休眠

用户类型

，如下所述：

域内类约束：

static constraints = {
   content type: JSONObjectUserType
}

用户类型类：

import org.grails.web.json.JSONObject
import org.hibernate.HibernateException
import org.hibernate.engine.spi.SessionImplementor
import org.hibernate.type.StandardBasicTypes
import org.hibernate.usertype.EnhancedUserType

import java.sql.PreparedStatement
import java.sql.ResultSet
import java.sql.SQLException
import java.sql.Types

class JSONObjectUserType implements EnhancedUserType, Serializable {

    private static final int[] SQL_TYPES = [Types.VARCHAR]

    @Override
    public int[] sqlTypes() {
        return SQL_TYPES
    }

    @Override
    public Class returnedClass() {
        return JSONObject.class
    }

    @Override
    public boolean equals(Object x, Object y) throws HibernateException {
        if (x == y) {
            return true
        }
        if (x == null || y == null) {
            return false
        }
        JSONObject zx = (JSONObject) x
        JSONObject zy = (JSONObject) y
        return zx.equals(zy)
    }

    @Override
    public int hashCode(Object object) throws HibernateException {
        return object.hashCode()
    }

    @Override
    public Object nullSafeGet(ResultSet resultSet, String[] names, SessionImplementor session, Object owner)
        throws HibernateException, SQLException {
        Object jsonObject = StandardBasicTypes.STRING.nullSafeGet(resultSet, names, session, owner)
        if (jsonObject == null) {
            return null
        }
        return new JSONObject((String) jsonObject)
    }

    @Override
    public void nullSafeSet(PreparedStatement preparedStatement, Object value, int index, SessionImplementor session)
        throws HibernateException, SQLException {
        if (value == null) {
            StandardBasicTypes.STRING.nullSafeSet(preparedStatement, null, index, session)
        } else {
            JSONObject jsonObject = (JSONObject) value
            StandardBasicTypes.STRING.nullSafeSet(preparedStatement, jsonObject.toString(), index, session)
        }
    }

    @Override
    public Object deepCopy(Object value) throws HibernateException {
        return value
    }

    @Override
    public boolean isMutable() {
        return false
    }

    @Override
    public Serializable disassemble(Object value) throws HibernateException {
        return (Serializable) value
    }

    @Override
    public Object assemble(Serializable cached, Object value) throws HibernateException {
        return cached
    }

    @Override
    public Object replace(Object original, Object target, Object owner) throws HibernateException {
        return original
    }

    @Override
    public String objectToSQLString(Object object) {
        throw new UnsupportedOperationException()
    }

    @Override
    public String toXMLString(Object object) {
        return object.toString()
    }

    @Override
    public Object fromXMLString(String string) {
        return new JSONObject(string)
    }
}

import org.grails.web.json.JSONObject
import org.hibernate.HibernateException
import org.hibernate.engine.spi.SessionImplementor
import org.hibernate.type.StandardBasicTypes
import org.hibernate.usertype.EnhancedUserType

import java.sql.PreparedStatement
import java.sql.ResultSet
import java.sql.SQLException
import java.sql.Types

class JSONObjectUserType implements EnhancedUserType, Serializable {

    private static final int[] SQL_TYPES = [Types.VARCHAR]

    @Override
    public int[] sqlTypes() {
        return SQL_TYPES
    }

    @Override
    public Class returnedClass() {
        return JSONObject.class
    }

    @Override
    public boolean equals(Object x, Object y) throws HibernateException {
        if (x == y) {
            return true
        }
        if (x == null || y == null) {
            return false
        }
        JSONObject zx = (JSONObject) x
        JSONObject zy = (JSONObject) y
        return zx.equals(zy)
    }

    @Override
    public int hashCode(Object object) throws HibernateException {
        return object.hashCode()
    }

    @Override
    public Object nullSafeGet(ResultSet resultSet, String[] names, SessionImplementor session, Object owner)
        throws HibernateException, SQLException {
        Object jsonObject = StandardBasicTypes.STRING.nullSafeGet(resultSet, names, session, owner)
        if (jsonObject == null) {
            return null
        }
        return new JSONObject((String) jsonObject)
    }

    @Override
    public void nullSafeSet(PreparedStatement preparedStatement, Object value, int index, SessionImplementor session)
        throws HibernateException, SQLException {
        if (value == null) {
            StandardBasicTypes.STRING.nullSafeSet(preparedStatement, null, index, session)
        } else {
            JSONObject jsonObject = (JSONObject) value
            StandardBasicTypes.STRING.nullSafeSet(preparedStatement, jsonObject.toString(), index, session)
        }
    }

    @Override
    public Object deepCopy(Object value) throws HibernateException {
        return value
    }

    @Override
    public boolean isMutable() {
        return false
    }

    @Override
    public Serializable disassemble(Object value) throws HibernateException {
        return (Serializable) value
    }

    @Override
    public Object assemble(Serializable cached, Object value) throws HibernateException {
        return cached
    }

    @Override
    public Object replace(Object original, Object target, Object owner) throws HibernateException {
        return original
    }

    @Override
    public String objectToSQLString(Object object) {
        throw new UnsupportedOperationException()
    }

    @Override
    public String toXMLString(Object object) {
        return object.toString()
    }

    @Override
    public Object fromXMLString(String string) {
        return new JSONObject(string)
    }
}