Hibernate数据库DATETIME类型字段映射为Date类型后的强制转型错误

Question

用Struts2 + Hibernate（3.3.1）做了一个测试程序，查询的时候遇到了强制转换类型错误，数据库是MySQL 5.0，麻烦看下代码，很简单。
异常提示：
[code="java"]
java.lang.ClassCastException: java.lang.String
at org.hibernate.type.DateType.toString(DateType.java:101)
at org.hibernate.type.NullableType.nullSafeToString(NullableType.java:117)
at org.hibernate.type.NullableType.nullSafeSet(NullableType.java:158)
at org.hibernate.type.NullableType.nullSafeSet(NullableType.java:136)
at org.hibernate.param.NamedParameterSpecification.bind(NamedParameterSpecification.java:61)
at org.hibernate.loader.hql.QueryLoader.bindParameterValues(QueryLoader.java:514)
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1589)
at org.hibernate.loader.Loader.doQuery(Loader.java:696)
…………
[/code]

Hibernate 映射文件：
[code="xml"]






<!-- MySQL数据库中TIME字段的类型为DATETIME -->



[/code]

DAO类
[code="java"]
package dao;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import model.SData;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class SDao {

private Session session = null;

private Transaction tx = null;

Map<String, String> map = null;

@SuppressWarnings("unchecked")
public List<SData> query( SData data ) {
    session = HibernateUtil.getCurrentSession();
    try {
        String hql = createSQL(data);
        Query query = HibernateUtil.getCurrentSession().createQuery(hql);

        Iterator<String> it = map.keySet().iterator();
        while (it.hasNext()) {
            String key = it.next();
            query.setParameter(key, map.get(key));
        }

        query.setMaxResults(512);
        List list = query.list();
        return list;
    }
    catch (HibernateException e) {
        HibernateUtil.rollbackTransaction();
    }

    return null;
}

private String createSQL( SData data ) {
    StringBuffer hql = new StringBuffer();
    hql.append("from SData as s where 1=1 ");

    map = new HashMap<String, String>();

    String value = data.getName();
    if (value != null && value.length() > 0) {
        map.put("name", "%" + value + "%");
        hql.append("and s.name like :name ");
    }

    value = data.getAddr();
    if (value != null && value.length() > 0) {
        map.put("addr", value);
        hql.append("and s.addr = :addr ");
    }

    Date time = data.getTime();
    if (time != null) {
        long now = time.getTime();
        now = now - now % 86400000 + 57600000;

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
        map.put("begin", sdf.format(new Date(now)));
        map.put("end", sdf.format(new Date(now + 86400000)));
        hql.append("and s.time between :begin and :end ");
    }

    value = data.getLine();
    if (value != null && value.length() > 0) {
        map.put("line", value);
        hql.append("and s.line = :line ");
    }

    return hql.toString();
}

}
[/code]

个人感觉应该不是大问题，不过我找了很久还是没想出来解决办法，实属无奈来此发帖劳烦大家，求帮忙，感激不尽。

Answer 1

    Date time = data.getTime();   
    if (time != null) {   
        long now = time.getTime();   
        now = now - now % 86400000 + 57600000;   

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");   
        map.put("begin", sdf.format(new Date(now)));   
        map.put("end", sdf.format(new Date(now + 86400000)));   
        hql.append("and s.time between :begin and :end ");   
    }  

这个地方就搞错了，你怎么把date转换成字符串保存成参数

while (it.hasNext()) {

String key = it.next();

//这个地方对给date类型的参数设置参数不能为字符串的，否则自然就出现上面的类型转换错误
query.[color=red]setParameter/color);

}