JPA(hibernate) Dao 和 DaoSupport

package cn.yisi.service.base;

import java.io.Serializable;
import java.util.LinkedHashMap;

import cn.yisi.bean.QueryResult;

public interface DAO<T> {
	
	/**
	 * 
	 * @param id 值 
	 * @param colName  列名
	 * @return
	 */
	public T getByID(String id,String colName);
	
	/**
	 * 获取记录总数
	 * @param entityClass 实体类
	 * @return
	 */
	public long getCount();
	/**
	 * 清除一级缓存的数据
	 */
	public void clear();
	/**
	 * 保存实体
	 * @param entity 实体id
	 */
	public void save(T entity);
	/**
	 * 更新实体
	 * @param entity 实体id
	 */
	public void update(T entity);
	/**
	 * 删除实体
	 * @param entityClass 实体类
	 * @param entityids 实体id数组
	 */
	public void delete(Serializable ... entityids);
	/**
	 * 获取实体
	 * @param <T>
	 * @param entityClass 实体类
	 * @param entityId 实体id
	 * @return
	 */
	public T find(Serializable entityId);
	/**
	 * 获取分页数据
	 * @param <T>
	 * @param entityClass 实体类
	 * @param firstindex 开始索引
	 * @param maxresult 需要获取的记录数
	 * @return
	 */
	public QueryResult<T> getScrollData(int firstindex, int maxresult, String wherejpql, Object[] queryParams,LinkedHashMap<String, String> orderby);
	
	public QueryResult<T> getScrollData(int firstindex, int maxresult, String wherejpql, Object[] queryParams);
	
	public QueryResult<T> getScrollData(int firstindex, int maxresult, LinkedHashMap<String, String> orderby);
	
	public QueryResult<T> getScrollData(int firstindex, int maxresult);
	
	public QueryResult<T> getScrollData();
}




package cn.yisi.service.base;

import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.LinkedHashMap;
import java.util.List;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import cn.yisi.bean.QueryResult;
import cn.yisi.utils.GenericsUtils;
import cn.yisi.utils.WebUtil;

@SuppressWarnings("unchecked")
@Transactional
public abstract class DaoSupport<T> implements DAO<T> {
	protected Class<T> entityClass = GenericsUtils.getSuperClassGenricType(this.getClass());
	@PersistenceContext
	protected EntityManager em;

	public void clear() {
		em.clear();
	}

	public void delete(Serializable... entityids) {
		for (Object id : entityids) {
			em.remove(em.getReference(this.entityClass, id));
		}
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public T find(Serializable entityId) {
		if (entityId == null)
			throw new RuntimeException(this.entityClass.getName() + ":传入的实体id不能为空");
		return em.find(this.entityClass, entityId);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public T getByID(String id, String colName) {
		String realColName = "id";
		if (!WebUtil.checkNull(colName)) {
			realColName = colName;
		}

		if (id == null || "".equals(id.trim()))
			throw new RuntimeException(this.entityClass.getName() + ":传入的实体id不能为空");
		List<T> list = em.createQuery("select o from " + getEntityName(this.entityClass) + " o where " + realColName + " = ?1").setParameter(1, id).getResultList();
		if (list != null && list.size() == 1) {
			return list.get(0);
		} else {
			return null;
		}

	}

	public void save(T entity) {
		em.persist(entity);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public long getCount() {
		return (Long) em.createQuery("select count(" + getCountField(this.entityClass) + ") from " + getEntityName(this.entityClass) + " o").getSingleResult();
	}

	public void update(T entity) {
		em.merge(entity);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public QueryResult<T> getScrollData(int firstindex, int maxresult, LinkedHashMap<String, String> orderby) {
		return getScrollData(firstindex, maxresult, null, null, orderby);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public QueryResult<T> getScrollData(int firstindex, int maxresult, String wherejpql, Object[] queryParams) {
		return getScrollData(firstindex, maxresult, wherejpql, queryParams, null);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public QueryResult<T> getScrollData(int firstindex, int maxresult) {
		return getScrollData(firstindex, maxresult, null, null, null);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public QueryResult<T> getScrollData() {
		return getScrollData(-1, -1);
	}

	@Transactional(readOnly = true, propagation = Propagation.NOT_SUPPORTED)
	public QueryResult<T> getScrollData(int firstindex, int maxresult, String wherejpql, Object[] queryParams, LinkedHashMap<String, String> orderby) {
		// 测试用--开始
		// System.out.println("wherejpql--->"+wherejpql);
		// for(int i=0;i<queryParams.length;i++){
		// System.out.println("queryParams"+i+"--->"+queryParams[i]);
		// }
		// 测试用--结束

		QueryResult qr = new QueryResult<T>();
		String entityname = getEntityName(this.entityClass);
		String tempSQLWhere = entityname + " o " + (wherejpql == null || "".equals(wherejpql.trim()) ? "" : "where " + wherejpql);
		String tempSQL = "select o from " + tempSQLWhere + buildOrderby(orderby);
		Query query = em.createQuery(tempSQL);
		setQueryParams(query, queryParams);
		if (firstindex != -1 && maxresult != -1) {
			query.setFirstResult(firstindex).setMaxResults(maxresult);
		}
		qr.setResultlist(query.getResultList());
		String tempCountSQL = "select count(" + getCountField(this.entityClass) + ") from " + tempSQLWhere;
		query = em.createQuery(tempCountSQL);
		setQueryParams(query, queryParams);
		qr.setTotalrecord((Long) query.getSingleResult());
		return qr;
	}

	protected static void setQueryParams(Query query, Object[] queryParams) {
		if (queryParams != null && queryParams.length > 0) {
			for (int i = 0; i < queryParams.length; i++) {
				query.setParameter(i + 1, queryParams[i]);
			}
		}
	}

	/**
	 * 组装order by语句
	 * 
	 * @param orderby
	 * @return
	 */
	protected static String buildOrderby(LinkedHashMap<String, String> orderby) {
		StringBuffer orderbyql = new StringBuffer("");
		if (orderby != null && orderby.size() > 0) {
			orderbyql.append(" order by ");
			for (String key : orderby.keySet()) {
				orderbyql.append("o.").append(key).append(" ").append(orderby.get(key)).append(",");
			}
			orderbyql.deleteCharAt(orderbyql.length() - 1);
		}
		return orderbyql.toString();
	}

	/**
	 * 获取实体的名称
	 * 
	 * @param <E>
	 * @param clazz
	 *            实体类
	 * @return
	 */
	protected static <E> String getEntityName(Class<E> clazz) {
		String entityname = clazz.getSimpleName();
		Entity entity = clazz.getAnnotation(Entity.class);
		if (entity.name() != null && !"".equals(entity.name())) {
			entityname = entity.name();
		}
		return entityname;
	}

	/**
	 * 获取统计属性,该方法是为了解决hibernate解析联合主键select count(o) from Xxx
	 * o语句BUG而增加,hibernate对此jpql解析后的sql为select
	 * count(field1,field2,...),显示使用count()统计多个字段是错误的
	 * 
	 * @param <E>
	 * @param clazz
	 * @return
	 */
	protected static <E> String getCountField(Class<E> clazz) {
		String out = "o";
		try {
			PropertyDescriptor[] propertyDescriptors = Introspector.getBeanInfo(clazz).getPropertyDescriptors();
			for (PropertyDescriptor propertydesc : propertyDescriptors) {
				Method method = propertydesc.getReadMethod();
				if (method != null && method.isAnnotationPresent(EmbeddedId.class)) {
					PropertyDescriptor[] ps = Introspector.getBeanInfo(propertydesc.getPropertyType()).getPropertyDescriptors();
					out = "o." + propertydesc.getName() + "." + (!ps[1].getName().equals("class") ? ps[1].getName() : ps[0].getName());
					break;
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return out;
	}
}