怎样使用泛型实现Hibernate查询返回对象
我可以给你demo，你可以参考
接口你可以自己写
package com.shopping.b2b.dao.impl;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import javax.annotation.Resource;
import javax.persistence.Table;
import org.apache.log4j.Logger;
import org.hibernate.Hibernate;
import org.hibernate.Query;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.transform.Transformers;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import com.shopping.b2b.dao.ISuperDao;
@Repository("superDao")
public class SuperDaoImpl implements ISuperDao{
@Resource
private SessionFactory hibernateSessionFactory;
public SessionFactory getHibernateSessionFactory() {
return hibernateSessionFactory;
}
public void setHibernateSessionFactory(SessionFactory hibernateSessionFactory) {
this.hibernateSessionFactory = hibernateSessionFactory;
}
private Logger logger = Logger.getLogger(this.getClass());
private Session getCurrentSession() {
return this.hibernateSessionFactory.getCurrentSession();
}
@Override
public <T> T get(Class<T> clazz, Serializable id) {
return (T)this.getCurrentSession().get(clazz, id);
}
@Override
public <T> T getSql(String sql, Map<String, Object> params, Class<T> po) {
SQLQuery q = this.getCurrentSession().createSQLQuery(sql);
/*
* say:
* 从数据库查出来的数据类型给po，如果要自定义，那么需要扩展addScalar
* 默认情况：数据库字段类型是什么类型，返回的po也是什么类型。移植性不好
* 可扩展
*/
if(po != null){
q.setResultTransformer(Transformers.aliasToBean(po));
}else{
q.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
}
if(params != null && !params.isEmpty()){
for (String k : params.keySet()) {
Object v = params.get(k);
if(v != null){
if(v instanceof Object[]){
q.setParameterList(k, (Object[])v);
}else if(v instanceof Collection<?>){
q.setParameterList(k, (Collection<?>)v);
}else{
q.setParameter(k, v);
};
}
}
}
List<T> list = q.list();
return list == null || list.isEmpty() ? null:list.get(0);
}
@Override
public Serializable save(Object entity) {
return this.getCurrentSession().save(entity);
}
@Override
public boolean update(Object entity) {
boolean result = false;
try {
this.getCurrentSession().update(entity);
result = true;
} catch (Exception e) {
result = false;
}
return result;
}
@Override
public boolean updateSql(String sql,Map<String, Object> params) {
SQLQuery q = this.getCurrentSession().createSQLQuery(sql);
if(params != null && !params.isEmpty()){
for (String k : params.keySet()) {
Object v = params.get(k);
if(v != null){
if(v instanceof Object[]){
q.setParameterList(k, (Object[])v);
}else if(v instanceof Collection<?>){
q.setParameterList(k, (Collection<?>)v);
}else{
q.setParameter(k, v);
};
}
}
}
return q.executeUpdate() == 0 ? false :true;
}
@Override
public boolean delete(Object entity) {
boolean result = false;
try {
this.getCurrentSession().delete(entity);
result = true;
} catch (Exception e) {
result = false;
}
return result;
}
@Override
public <T> boolean deleteSql(Class<T> clazz,Serializable id) {
boolean result = false;
try {
Table table = (Table)clazz.getAnnotation(Table.class);
if(table != null){
String tableName = table.name();
this.getCurrentSession()
.createSQLQuery("delete from :tableName where id = :id")
.setParameter("tableName", tableName)
.setParameter("id", id)
.executeUpdate();
}
result = true;
} catch (Exception e) {
result = false;
}
return result;
}
@Override
public <T> List<T> queryList(String sql, Map<String, Object> params, Class<T> po) {
SQLQuery q = this.getCurrentSession().createSQLQuery(sql);
/*
* say:
* 从数据库查出来的数据类型给po，如果要自定义，那么需要扩展addScalar
* 默认情况：数据库字段类型是什么类型，返回的po也是什么类型。移植性不好
* 可扩展
*/
if(po != null){
q.setResultTransformer(Transformers.aliasToBean(po));
}else{
q.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);
}
if(params != null && !params.isEmpty()){
for (String k : params.keySet()) {
Object v = params.get(k);
if(v != null){
if(v instanceof Object[]){
q.setParameterList(k, (Object[])v);
}else if(v instanceof Collection<?>){
q.setParameterList(k, (Collection<?>)v);
}else{
q.setParameter(k, v);
}
}
}
}
List<T> list = q.list();
return list == null || list.isEmpty() ? null:list;
}
@Override
public <T> List<T> queryList(String sql, Map<String, Object> params, int firstResult, int maxResults, Class<T> po) {
SQLQuery query = this.getCurrentSession().createSQLQuery(sql);
/*
* say:
* 从数据库查出来的数据类型给po，如果要自定义数据类型，那么需要扩展addScalar
* 默认情况：数据库字段类型是什么类型，返回的po也是什么类型。移植性不好
* 可扩展
*/
if(po != null){
query.setResultTransformer(Transformers.aliasToBean(po)).setFirstResult(firstResult).setMaxResults(maxResults);
}else{
query.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP).setFirstResult(firstResult).setMaxResults(maxResults);
}
//this.addScalarsToString(query, po).setFirstResult(firstResult).setMaxResults(maxResults);//test
if(params != null && !params.isEmpty()){
for (String k : params.keySet()) {
Object v = params.get(k);
if(v != null){
if(v instanceof Object[]){
query.setParameterList(k, (Object[])v);
}else if(v instanceof Collection<?>){
query.setParameterList(k, (Collection<?>)v);
}else{
query.setParameter(k, v);
}
}
}
}
List<T> list = query.list();
return list == null || list.isEmpty() ? null:list;
}
@Override
public <T> Serializable queryCount(String sql, Map<String, Object> params) {
Query query = this.getCurrentSession().createSQLQuery(sql);
if(params != null && !params.isEmpty()){
for (String k : params.keySet()) {
Object v = params.get(k);
if(v != null){
if(v instanceof Object[]){
query.setParameterList(k, (Object[])v);
}else if(v instanceof Collection<?>){
query.setParameterList(k, (Collection<?>)v);
}else{
query.setParameter(k, v);
}
}
}
}
return Integer.parseInt(query.uniqueResult().toString());
}
/**
* 扩展
* 默认将class的属性类型转换为hibernate所对应的的类型<br/>
* 如果严格的话请使用Transformers.aliasToBean(T.class)<br/>
* 对应表如下：
* 未实现
* @param query
* @param cls
* @return
*/
private <T> Query addScalarsToCustom(SQLQuery query,Class<T> cls){
Field[] fields = cls.getDeclaredFields();
for(Field item:fields){
////System.out.println(item.getName() + ":" + item.getGenericType());
//该接口需要判断，返回的属性类型，然后转换为hibernate语法
//System.out.println(item.getName() + ":" + item.getGenericType());
//该接口需要判断，返回的属性类型，然后转换为hibernate语法
if("class java.math.BigInteger".equals(item.getGenericType().toString())){
//System.out.println(cls.getName() +":"+item.getName() + " ||==int");
}else if("class java.lang.String".equals(item.getGenericType().toString())){
//System.out.println(cls.getName() +":"+item.getName() + " ||==String");
}else if("class java.math.BigDecimal".equals(item.getGenericType().toString())){
//System.out.println(cls.getName() +":"+item.getName() + " ||==String");
}else{
//System.out.println(cls.getName() +":"+item.getName() + " ||==未匹配类型");
}
}
return null;
}
}
