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package com.itcast.service.base;
import java.util.LinkedHashMap;
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 com.itcast.util.QueryResult;
/**
* Õë¶ÔËùÓÐʵÌåbeanµÄÒ»¸ö³éÏóÀ࣬ËùÓеÄʵÌåbean°üÀ¨ProductType,ProductµÈµÈ
* @author lucky
*
*/
@Transactional
public abstract class DaoSupport implements DAO {
@PersistenceContext protected EntityManager em;
//µ÷ÓÃÏÂÃæµÄpublic <T> void delete(Class<T> entityClass,Object[] entityids·½·¨
public <T> void delete(Class<T> entityClass,Object entityid) {
delete(entityClass,new Object[]{entityid});
}
public <T> void delete(Class<T> entityClass,Object[] entityids) {
for(Object id:entityids){
em.remove(em.getReference(entityClass, id));
}
}
@Transactional(readOnly=true,propagation=Propagation.NOT_SUPPORTED)//˵Ã÷ÔÚÖ´Ðи÷½·¨µÄʱºò²»ÐèÒª½øÐÐÊÂÎñ´¦Àí
public <T> T find(Class<T> entityClass, Object entityid) {
return em.find(entityClass, entityid);
}
/**
* ¿ÉÒÔ×Ô¶¯¹ÜÀïÖ÷¼üidµÄÉú³É£¬µ«Ç°ÌáÊÇidÊÇ×Ô¶¯Éú³ÉµÄ
* ÈôidÊÇuuidµÄ»°£¬jpa¾Í²»Ö§³Ö×Ô¶¯¹ÜÀíÖ𽥵ŦÄÜ£¬×ÓÀà¾Í±ØÐëÖØÐ´¸Ã·½·¨£¬ÊÖ¶¯Ìí¼ÓÖ÷¼ü
*/
public void save(Object entity) {
em.persist(entity);
}
public void update(Object entity) {
em.merge(entity);
}
@SuppressWarnings("unchecked")
@Transactional(readOnly=true,propagation=Propagation.NOT_SUPPORTED)
/**
* ²éѯµÄÖÕ¼«×îÇ¿°æ£¬¼È¿ÉÒÔ·ÖÒ³£¬ÓÖ¿ÉÒÔ°´Ðò²éѯ£¬»¹¿ÉÒÔÓвéѯÌõ¼þ£¬ÆäËûµÄ²éѯ¶¼Ê¹ÓÃÕâ¸ö²éѯ·½·¨
* orderby Óï¾ä¸ñʽ£ºorder by key1 asc
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avg([distinct]column_name)
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select AVG(emp_salary)
from employee;
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character-set-server = GB2312
collation-server = latin1_general_ci
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MySQLÖÐÉæ¼°µÄ¼¸¸ö×Ö·û¼¯
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import java.sql.*;
/*
* JAVAÁ¬½ÓACCESS£¬SQL Server,MySQL,OracleÊý¾Ý¿â
*
* */
public class JDBC {
public static void main(String[] args)throws Exception {
Connection conn=null;
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