实现按条件查询
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2022-04-22 08:59:19
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第一步: 定义接口: public interface ICommonDaoT { ListT findCollectionByConditionNoPage(String codition,Object[] params, MapString, String orderby); } 第二步: 实现接口的类: Class entityClass = TUtils.getTClass(this.getClass());public cl
第一步:
定义接口:
public interface ICommonDao
List
}
第二步:
实现接口的类:
Class entityClass = TUtils.getTClass(this.getClass()); public class TUtils { /**泛型转换,目的获取子类传递父类的真实类型,也就是T所对应的类型*/ public static Class getTClass(Class entity) { ParameterizedType type = (ParameterizedType)entity.getGenericSuperclass(); Class entityClass = (Class) type.getActualTypeArguments()[0]; return entityClass; } }
/**指定查询条件查询对应的结果,返回List(不分页)*/ /** * FROM ElecText o WHERE 1=1 #Dao层 AND o.textName LIKE '%张%' #Service层 AND o.textRemark LIKE '%张%' #Service层 ORDER BY o.textDate ASC,o.textName DESC #Service层 */ public ListfindCollectionByConditionNoPage(String condition, final Object[] params, Map orderby) { //定义hql语句 String hql = "FROM "+entityClass.getSimpleName()+" o WHERE 1=1"; //定义排序语句 String orderbyHql = this.orderbyHql(orderby); //定义最终的语句 final String finalHql = hql + condition + orderbyHql; //执行语句一 //List list = this.getHibernateTemplate().find(finalHql, params); //执行语句二 // SessionFactory sf = this.getHibernateTemplate().getSessionFactory(); // Session s = sf.getCurrentSession(); // Query query = s.createQuery(finalHql); // List list = query.list(); //执行语句三 List list = this.getHibernateTemplate().execute(new HibernateCallback() { public Object doInHibernate(Session session) throws HibernateException, SQLException { Query query = session.createQuery(finalHql); if(params!=null && params.length>0){ for(int i=0;i orderby) { StringBuffer buffer = new StringBuffer(""); if(orderby!=null && orderby.size()>0){ buffer.append(" order by "); for(Map.Entry map:orderby.entrySet()){ buffer.append(map.getKey()+" "+map.getValue()+","); } //删除最后一个逗号 buffer.deleteCharAt(buffer.length()-1); } return buffer.toString(); }
下面是根据不同的业务来编写不同的代码。
第三步:
service接口:
public interface IElecTextService { public static final String SERVICE_NAME = "com.itheima.elec.service.impl.ElecTextServiceImpl"; ListfindCollectionByConditionNoPage(ElecText elecText); }
第四步:
service实现
/**指定查询条件查询对应的结果,返回List*/ /** * FROM ElecText o WHERE 1=1 #Dao层 AND o.textName LIKE '%张%' #Service层 AND o.textRemark LIKE '%张%' #Service层 ORDER BY o.textDate ASC,o.textName DESC #Service层 */ public ListfindCollectionByConditionNoPage(ElecText elecText) { //查询条件 String condition = ""; List
第五步:
/**模拟Action,调用Service,指定查询条件查询对应的结果,返回List*/ @Test public void findCollectionByConditionNoPage(){ ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml"); IElecTextService elecTextService = (IElecTextService) ac.getBean(IElecTextService.SERVICE_NAME); ElecText elecText = new ElecText(); // elecText.setTextName("张"); // elecText.setTextRemark("张"); Listlist = elecTextService.findCollectionByConditionNoPage(elecText); if(list!=null && list.size()>0){ for(ElecText elecText2:list){ System.out.println(elecText2.getTextName()+" "+elecText2.getTextDate()+" "+elecText2.getTextRemark()); } } }
真正的action:
package com.itheima.elec.web.action; import java.util.List; import javax.annotation.Resource; import org.springframework.context.annotation.Scope; import org.springframework.stereotype.Controller; import com.itheima.elec.domain.ElecSystemDDL; import com.itheima.elec.service.IElecSystemDDLService; @SuppressWarnings("serial") @Controller("elecSystemDDLAction") @Scope(value="prototype") public class ElecSystemDDLAction extends BaseAction总结:根据什么样的条件查询,是在service层完成的,把所有的条件组织好后,给dao层,dao层再拼接SQL或者hql语句,进行真正的查询。web层的action只是传递参数,进行简单的调用service层的方法。{ ElecSystemDDL elecSystemDDL = this.getModel(); @Resource(name=IElecSystemDDLService.SERVICE_NAME) private IElecSystemDDLService elecSystemDDLService; public String home(){ List list = elecSystemDDLService.findKeywordWithDistinct(); request.setAttribute("list", list); return "home"; } public String edit(){ //获取数据类型 String keyword = elecSystemDDL.getKeyword(); //1:使用数据类型作为查询条件,查询数据字典表,返回List List list = elecSystemDDLService.findSystemDDLListByKeyword(keyword); request.setAttribute("systemList", list); return "edit"; } }