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我的hql语句是这样写的 String hql = "select new News(n.newsId,n.newsTitle,n.newsTime,n.newsPic) from News n order by n.newsTime desc"; 这样查出来会报错,说没有适合的构造函数,但是我写了对应的构造函数了。 我的数据库是mysql5.5,数据库中这个newsTime是timestamp类型的;然后用myeclipse生成的映射文件中,newsTime是timestamp类型的。 org.hibernate.hql.ast.QuerySyntaxException: Unable to locate appropriate constructor on class [model.News] [select new News(n.newsId,n.newsTitle,n.newsTime,n.newsPic) from model.News n order by n.newsTime desc] at org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:54) at org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:47) at org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:82) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:258) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:183) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:134) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:94) at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:156) at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:135) at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1650) at dao.NewsDaoImpl.getNewsList(NewsDaoImpl.java:32) at service.NewsServiceImpl.getNewsList(NewsServiceImpl.java:23) at action.NewsAction.execute(NewsAction.java:84) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:870) 我的News类:
package model;
import java.sql.Timestamp;
/**
* News entity. @author MyEclipse Persistence Tools
*/
public class News implements java.io.Serializable {
// Fields
private Integer newsId;
private String newsTitle;
private Timestamp newsTime;
private Integer newsEditorId;
private String newsEditor;
private Integer newsPic;
private String newsContent;
// Constructors
/** default constructor */
public News() {
}
//id,標題,圖片
public News(Integer newsId, String newsTitle, Integer newsPic) {
this.newsId = newsId;
this.newsTitle = newsTitle;
this.newsPic = newsPic;
}
//id,標題,時間,圖片
public News(Integer newsId, String newsTitle, Timestamp newsTime,
Integer newsPic) {
this.newsId = newsId;
this.newsTitle = newsTitle;
this.newsTime = newsTime;
this.newsPic = newsPic;
}
/** full constructor */
public News(String newsTitle, Timestamp newsTime, Integer newsEditorId, String newsEditor, Integer newsPic, String newsContent) {
this.newsTitle = newsTitle;
this.newsTime = newsTime;
this.newsEditorId = newsEditorId;
this.newsEditor = newsEditor;
this.newsPic = newsPic;
this.newsContent = newsContent;
}
// Property accessors
public Integer getNewsId() {
return this.newsId;
}
public void setNewsId(Integer newsId) {
this.newsId = newsId;
}
public String getNewsTitle() {
return this.newsTitle;
}
public void setNewsTitle(String newsTitle) {
this.newsTitle = newsTitle;
}
public Timestamp getNewsTime() {
return this.newsTime;
}
public void setNewsTime(Timestamp newsTime) {
this.newsTime = newsTime;
}
public Integer getNewsEditorId() {
return this.newsEditorId;
}
public void setNewsEditorId(Integer newsEditorId) {
this.newsEditorId = newsEditorId;
}
public String getNewsEditor() {
return this.newsEditor;
}
public void setNewsEditor(String newsEditor) {
this.newsEditor = newsEditor;
}
public Integer getNewsPic() {
return this.newsPic;
}
public void setNewsPic(Integer newsPic) {
this.newsPic = newsPic;
}
public String getNewsContent() {
return this.newsContent;
}
public void setNewsContent(String newsContent) {
this.newsContent = newsContent;
}
}
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#1 |
new 后面加个实体对象这样没用过,我记得以前这样用过
select new map(n.newsId,n.newsTitle,n.newsTime,n.newsPic)这样看行不行 |
#2 |
select 的里面这个 感觉怪怪的,能直接这样写?new News(n.newsId,n.newsTitle,n.newsTime,n.newsPic)
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#320分 |
private Timestamp newsTime;
修改为 private java.util.Date newsTime试验一下? 另外,我写了个代码来测试你说的问题,我的hibernate会报如下错误,为虾米你的没有? 你的hibernate版本太老? 有下面的错误提示能更快速的定位问题 |
#4 |
回复3楼:
改了类型,还是无法解决,最终我放弃了这种酷炫的hql写法。哎
最终代码是
String hql = "select newsId,newsTitle,newsTime,newsPic from News order by newsTime desc";
List<Object[]> list = session.createQuery(hql)
.setFirstResult(fristResult).setMaxResults(maxResult)
.list();
newsList = new ArrayList<News>();
for (Object[] object : list) {
News n = new News();
n.setNewsId((Integer) object[0]);
n.setNewsTitle((String) object[1]);
n.setNewsTime((Timestamp) object[2]);
n.setNewsPic((Integer) object[3]);
newsList.add(n);
}
但,原来的那个为啥不能用,还是不知道。不甘心啊 |
#5 |
回复4楼: 那个写法没有问题,我亲测可用。你升级一下hibernate,看看是不是想哦这样报错:明确的说需要什么样Constructor。 |
#6 |
回复5楼:
恩,确实是我的hibernate版本太老,升级到最新的之后,就不报错了。
谢谢啦~ |