在mysql做資料庫的應用中，日期型別經常回儲存為int（10）型別。方便排序和計算。但是在java中用Date.getTime返回的是13位的Long。並且在實體中我們如果用long來儲存會有諸多不便。所以涉及到了轉換問題。在我的專案中，用的是mybatis做永續性框架。對於這個問題用了以下方法處理。

1. 用mybatis generate時，配置實體中用date來覆蓋資料庫中的int型別。

<columnOverride column="birthday" javaType="java.util.Date" jdbcType="INTEGER" />  

1. 自定義TypeHandler實現TypeHandler介面

@MappedTypes({ Date.class })  
@MappedJdbcTypes({ JdbcType.INTEGER })  
public class DateIntTypeHandler implements TypeHandler<Date> {  

    @Override  
    public void setParameter(PreparedStatement ps, int i, Date parameter,  
            JdbcType jdbcType) throws SQLException {  
        if
 
 (parameter == null) {  
            if (jdbcType == null) {  
                throw new TypeException(  
                        "JDBC requires that the JdbcType must be specified for all nullable parameters.");  
            }  
            try {  
                ps.setNull(i, jdbcType.TYPE_CODE);  
            } catch
 
 (SQLException e) {  
                throw new TypeException(  
                        "Error setting null for parameter #"  
                                + i  
                                + " with JdbcType "  
                                + jdbcType  
                                + " . "  
                                + "Try setting a different JdbcType for this parameter or a different jdbcTypeForNull configuration property. "  
                                + "Cause: " + e, e);  
            }  
        } else {  
            int time = (int) (parameter.getTime() / 1000);  
            ps.setInt(i, time);  
        }  
    }  

    @Override  
    public Date getResult(ResultSet rs, String columnName) throws SQLException {  
        int res = rs.getInt(columnName);  
        long time = res * 1000L;  
        return new Date(time);  
    }  

    @Override  
    public Date getResult(ResultSet rs, int columnIndex) throws SQLException {  
        int res = rs.getInt(columnIndex);  
        long time = res * 1000L;  
        return new Date(time);  
    }  

    @Override  
    public Date getResult(CallableStatement cs, int columnIndex)  
            throws SQLException {  
        int res = cs.getInt(columnIndex);  
        long time = res * 1000L;  
        return new Date(time);  
    }  
}  

1. 在mybatis的配置中引用自定義的轉換處理類

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  
        <property name="dataSource" ref="dataSource" />  
        <!-- 自動掃描mapping.xml檔案 -->  
        <property name="mapperLocations" value="classpath:sqlmap/mysql/module/*/*.xml"></property>  
        <strong><property name="typeHandlers">  
            <array>  
                <bean name="dateIntTypeHandler" class="*.utils.mybatis.DateIntTypeHandler" />  
            </array>  
        </property></strong>  
    </bean>