Hib 4000 ernate的HQL和原生SQL返回简单对象

最近跟了一个技术经理，他有个要求就是所有的查询比结果都必需是对象，不是是map之类的,而且有很多对象的是很多实体相联合组成的对象,所有又专门研究了hibernate返回对象的知识

这次讨论的对象都是组合对象，就是很多实体相关联，取他们一部分字段的组合对象,

Hql

首先扩展的对象

package com.hfview.bean;

import java.util.ArrayList;
import java.util.List;

public class PersonEx {

private String id;
private String name;
private String birthday;
private String area;
private List<Menu> menu = new ArrayList<Menu>();

public PersonEx(){

}

public PersonEx(String name, String area) {
super();
this.name = name;
this.area = area;
}

public PersonEx(String id, String name, String birthday) {
super();
this.id = id;
this.name = name;
this.birthday = birthday;
}

public String getId() {
return id;
}

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

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getBirthday() {
return birthday;
}

public void setBirthday(String birthday) {
this.birthday = birthday;
}

public List<Menu> getMenu() {
return menu;
}

public void setMenu(List<Menu> menu) {
this.menu = menu;
}

public String getArea() {
return area;
}

public void setArea(String area) {
this.area = area;
}
}

实体Person1

package com.hfview.bean;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
import javax.persistence.Table;

@Table(name = "t_person",schema="zhw")
@Entity
public class Person1 {

private String id;
private String name;
private String sex;
private Card card;

@Id
@Column(name="ID")
public String getId() {
return id;
}

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

@Column(name="NAME")
public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

@Column(name="SEX",columnDefinition="varchar2(8)")
public String getSex() {
return sex;
}

public void setSex(String sex) {
this.sex = sex;
}

@OneToOne
@JoinColumn(name="CARDID")
public Card getCard() {
return card;
}

public void setCard(Card card) {
this.card = card;
}

}

实体Card

package com.hfview.bean;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Table(name = "t_card",schema="zhw")
@Entity
public class Card {

private String id;
private String cardId;
private String area;

@Id
@Column(name="ID")
public String getId() {
return id;
}

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

@Column(name="CARDID")
public String getCardId() {
return cardId;
}

public void setCardId(String cardId) {
this.cardId = cardId;
}

@Column(name="AREA")
public String getArea() {
return area;
}

public void setArea(String area) {
this.area = area;
}

}

Person1和card是一对一关系，PersonEx是这两个扩展对象

public List<PersonEx> getListPersonEx1(){
String hql=" select new com.hfview.bean.PersonEx(a.name,b.area) from Person1 a left join a.card b ";
return getHt().find(hql);
}

这样就动态的取到了PersonEx的集合。

这里需要注意几点

1、PersonEx里面一定要有对应的构造方法，并且sql里面参数顺序和构造器里面的顺序一致

2、PersonEx可以是没有映射关系的，也可以是实体

原生SQL

类 Person2

package com.hfview.bean;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Table(name = "t_person", schema = "zhw")
@Entity
public class Person2 {
private String id;
private int age;
private Date birthday;
private List<Menu> menu = new ArrayList<Menu>();

@Id
@Column(name="ID")
public String getId() {
return id;
}

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

@Column(name="AGE")
public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

@Column(name="BIRTHDAY")
public Date getBirthday() {
return birthday;
}

public void setBirthday(Date birthday) {
this.birthday = birthday;
}

@OneToMany
@JoinColumn(name="PERSONID")
public List<Menu> getMenu() {
return menu;
}

public void setMenu(List<Menu> menu) {
this.menu = menu;
}

}

Dao层方法

public List<PersonEx> getListPersonEx2(){
String sql="select a.id as \"id\",a.name as \"name\",to_char(a.birthday,'yyyy-mm-dd') as \"birthday\"  " +
"from t_person a  ";
return getForListBean(sql, PersonEx.class);
}

getForListBean方法

public <T> List<T> getForListBean(final String sql,final Map<String,Object> paras,final int page,final int rows,final Class<T> clazz){
return ht.executeFind(new HibernateCallback<List<HashMap<String,Object>>>() {

public List<HashMap<String, Object>> doInHibernate(
Session session) throws HibernateException, SQLException {
SQLQuery query = session.createSQLQuery(sql);

if(paras!=null){
for (String key :paras.keySet()) {
query.setParameter(key, paras.get(key));
}
}
if(page!=0&&rows!=0){
int start = page*rows-rows+1;
query.setFirstResult(start).setMaxResults(rows);
}

query.setResultTransformer(Transformers.aliasToBean(clazz));
return query.list();
}
});
}

这里需要注意的几点

1、构造函数一定要和sql里面的对应

2、oracle中默认把字段都转成大写，这样set方法就会出错，所以要转变成 as “aa” 这种

3、对于PersonEx如果有集合，怎么动态的设置进去，目前我还没找到方法