Java 将MySQL中的字符（0）映射到Hibernate中的布尔值

我在mysql（5.5版）中有一个名为

return\u rule

的表。以下是它的定义：

CREATE TABLE `refund_rule` (
  `ID` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `PERCENTAGE` char(0) DEFAULT NULL COMMENT 'BOOLEAN shortcut.NULL<=>false,EMPTY<=>true',
  `DEDUCTION_AMOUNT` int(10) unsigned DEFAULT NULL,
  PRIMARY KEY (`ID`)
);

NetBeans（7.0版）中向导生成的类如下：

public class RefundRule  implements java.io.Serializable {

     private Integer id;
     private String percentage;
     private Integer deductionAmount;

    public CancellationRule() {
    }

    public CancellationRule(String percentage, Integer deductionAmount) {
       this.percentage = percentage;
       this.deductionAmount = deductionAmount;
    }

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

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

    public String getPercentage() {
        return this.percentage;
    }

    public void setPercentage(String percentage) {
        this.percentage = percentage;
    }

    public Integer getDeductionAmount() {
        return this.deductionAmount;
    }

    public void setDeductionAmount(Integer deductionAmount) {
        this.deductionAmount = deductionAmount;
    }

}

我在其中添加了另外两个方法

setPercentage（boolean）

&

isPercentage（）

，并更改了方法

setPercentage（String）

，这样我就可以在Java（1.6版）程序中将该

String

对象用作

boolean

我的问题是:

有什么方法可以让我只保留两个方法：

setPercentage（boolean）

和

isPercentage（）

，并将

boolean percentage

变量映射到mysql中的

percentage CHAR（0）

变量

===================================================================

2013年11月23日新增编辑

根据@greybeardgeek的回答，我在代码中做了以下更改：

（简要更改）

添加了类ChartBoluserType

更改了hbm元素的

类型

-属性：returnRule.hbm.xml中的百分比

（与上述变更相关的代码）

ChartBoolUserType类：

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;

public class CharToBoolUserType implements UserType {

    private static final int[] SQL_TYPES = {Types.CHAR};

    @Override
    public Object assemble(Serializable serializable, Object object) throws HibernateException {
        return serializable;
    }

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

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

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

    @Override
    public boolean isMutable() {
        return false;
    }

    @Override
    public Object nullSafeGet(ResultSet resultSet, String[] names, Object owner) throws HibernateException, SQLException {
        return resultSet.getObject(names[0]) != null;
    }

    @Override
    public void nullSafeSet(PreparedStatement preparedStatement, Object value, int index) throws HibernateException, SQLException {
        preparedStatement.setObject(index, ((Boolean) value).booleanValue() ? "" : null);
    }

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

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

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

    @Override
    public int hashCode(Object object) throws HibernateException {
        if (object == null) {
            return 0;
        }
        // is `object` a String ? Or boolean?
        return 1;
    }
}

文件returnrule.hbm.xml：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="hibernatesample.dao.RefundRule" table="refund_rule" catalog="back_end_proc">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="identity" />
        </id>
        <property name="percentage" type="hibernatesample.dao.CharToBoolUserType">
            <column name="PERCENTAGE" length="0">
                <comment>BOOLEAN shortcut.NULL&lt;=&gt;false,EMPTY&lt;=&gt;true</comment>
            </column>
        </property>
        <property name="deductionAmount" type="java.lang.Integer">
            <column name="DEDUCTION_AMOUNT" />
        </property>
    </class>
</hibernate-mapping>

---

我相信您正在寻找Hibernate的用户类型，它允许您提供自定义类型映射

比如说,

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;

public class CharToBoolUserType implements UserType {

    private static final int[] SQL_TYPES = {Types.CHAR};

    @Override
    public Object assemble(Serializable serializable, Object object) throws HibernateException {
        return serializable;
    }

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

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

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

    @Override
    public boolean isMutable() {
        return false;
    }

    @Override
    public Object nullSafeGet(ResultSet resultSet, String[] names, Object owner) throws HibernateException, SQLException {
        return resultSet.getObject(names[0]) != null;
    }

    @Override
    public void nullSafeSet(PreparedStatement preparedStatement, Object value, int index) throws HibernateException, SQLException {
        preparedStatement.setObject(index, ((Boolean) value).booleanValue() ? "" : null);
    }

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

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

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

    @Override
    public int hashCode(Object object) throws HibernateException {
        if (object == null) {
            return 0;
        }
        // is `object` a String ? Or boolean?
        return 1;
    }
}

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="hibernatesample.dao.RefundRule" table="refund_rule" catalog="back_end_proc">
        <id name="id" type="java.lang.Integer">
            <column name="ID" />
            <generator class="identity" />
        </id>
        <property name="percentage" type="hibernatesample.dao.CharToBoolUserType">
            <column name="PERCENTAGE" length="0">
                <comment>BOOLEAN shortcut.NULL&lt;=&gt;false,EMPTY&lt;=&gt;true</comment>
            </column>
        </property>
        <property name="deductionAmount" type="java.lang.Integer">
            <column name="DEDUCTION_AMOUNT" />
        </property>
    </class>
</hibernate-mapping>

public class RefundRule  implements java.io.Serializable {

     private Integer id;
     private boolean percentage;
     private Integer deductionAmount;

    public RefundRule() {
    }


    public RefundRule(boolean percentage, Integer deductionAmount) {
        this.percentage = percentage;
        this.deductionAmount = deductionAmount;
    }

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

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

    public Integer getDeductionAmount() {
        return this.deductionAmount;
    }

    public void setDeductionAmount(Integer deductionAmount) {
        this.deductionAmount = deductionAmount;
    }

    public void setPercentage(boolean percentage){
        this.percentage=percentage;
    }

    public boolean isPercentage(){
        return percentage;
    }

}