91---Criteria的内链接，分页，查询唯一对象，条件查询，分组统计，投影查询，DetachedCriteria

Restrictions.like(属性名, 查询条件的值, 匹配方式)：

Restrictions.in(属性名, 查询条件的值, 匹配方式)：

Restrictions.eq(属性名, 查询条件的值, 匹配方式)：

 

Criteria Query常用的查询限制方法

Restrictions.eq() equal，=
Restrictions.allEq() 参数为Map对象，使用key/value进行多个等于的对比，相当于多个Restrictions.eq()的效果
Restrictions.gt() greater-than, >
Restrictions.lt() less-than, <
Restrictions.le() less-equal, <=
Restrictions.between() 对应SQL的between子句
Restrictions.like() 对应SQL的like子句
Restrictions.in() 对应SQL的in子句
Restrictions.and() and关系
Restrictions.or() or关系
Restrictions.isNull() 判断属性是否为空，为空返回true，否则返回false
Restrictions.isNotNull() 与Restrictions.isNull()相反
Order.asc() 根据传入的字段进行升序排序
Order.desc() 根据传入的字段进行降序排序
MatchMode.EXACT 字符串精确匹配，相当于“like 'value'”
MatchMode.ANYWHERE 字符串在中间位置，相当于“like '%value%'”
MatchMode.START 字符串在最前面的位置，相当于“like 'value%'”
MatchMode.END 字符串在最后面的位置，相当于“like '%value'”

 

public List search(TblFwxx condition) {

  Session session = this.getSession();

  Criteria c = session.createCriteria(TblFwxx.class);

 

  if (null != condition) {

    if (condition.getTitle() != null && !condition.getTitle().equals("")) {

      c.add(Restrictions.like("title", condition.getTitle(), MatchMode.ANYWHERE));   

    }

  } 

 

  c.addOrder(Order.asc("fwid"));

  return c.list();

 

}

 

-------------------------------------------------------------------------------------

例1：

表中的数据为:
userid name username password age
------------------------------------------------
  1    张三  zhang3   zhang3   20
  2    李四   li4      li4     21
  3    your  test     test     30

 

Session session = HibernateSessionFactory.getSession();
Criteria criteria = session.createCriteria(Test.class);
List list = criteria.add(Restrictions.like("name", "%your%"))
.add(Restrictions.like("username", "test"))
.add(Restrictions.eq("age", 30))
.list();

------------------------------------------------------------------------------------

例2：

 

private Session session;

public List criteria(SalChance salChance) {
  List result = null;  
     try { 
      session = super.getSession(); 
         Criteria cri = session.createCriteria(SalChance.class);
         if(salChance.getChcCustName()!=null&&salChance.getChcCustName()!=""){
          cri.add(Restrictions.like("chcCustName", salChance.getChcCustName(),MatchMode.ANYWHERE));
         }
         if(salChance.getChcTitle()!=null&&salChance.getChcTitle()!=""){
          cri.add(Restrictions.like("chcTitle", salChance.getChcTitle(),MatchMode.ANYWHERE));
         }
         if(salChance.getChcLinkman()!=null&&salChance.getChcLinkman()!=""){
          cri.add(Restrictions.like("chcLinkman", salChance.getChcLinkman(),MatchMode.ANYWHERE));
         }
         if(salChance.getChcStatus()!=null&&salChance.getChcStatus()!=""){
          //System.out.println("状态为："+salChance.getChcStatus());
          if(salChance.getChcStatus()=="all"){
           cri.add(Restrictions.in("chcStatus", new Object[]{"2","3","4"}));
          }else{
           cri.add(Restrictions.eq("chcStatus", salChance.getChcStatus()));
          }
         }
         result=cri.list();
            
     } catch (Exception e) { 
      e.printStackTrace();
     }finally {   
            session.close();
        }  

        return result;

2.Criteria查询使用org.hibernate.criterion.Order类对查询结果排序

List<Emp>list =session.createCriteria(Emp.class)

       .add(Restrictions.gt("salary", 4000D))

        .addOrder(Order.asc("salary"))

        .addOrder(Order.desc("empNo")).list();

3.Criteria接口提供了设置分页的方法

setFirstResult(intfirstResult)

setMaxResults(intmaxResult)

4.查询唯一对象

Empemp= (Emp)session.createCriteria(Emp.class)

        .add(Restrictions.isNotNull("salary"))

        .addOrder(Order.desc("salary"))

        .setMaxResults(1)

        .uniqueResult();

   方法 说明                             Query Criteria
list()        返回List集合                    支持 支持
iterate() 返回Iterator迭代器，只查询出ID值。 支持 不支持
uniqueResult() 返回唯一对象               支持 支持

5.Criteria接口提供了createCriteria()和createAlias()方法建立内连接

List<Emp>list =session.createCriteria(Emp.class)

        .add(Restrictions.ilike("empName","a",MatchMode.ANYWHERE))

        .createCriteria("dept")

        .add(Restrictions.eq("deptName","财务部").ignoreCase()).list();

List<Emp>list =session.createCriteria(Emp.class,"e")

        .createAlias("dept","d")

        .add(Restrictions.ilike("e.empName","a",

                MatchMode.ANYWHERE))

        .add(Restrictions.eq("d.deptName","财务部").ignoreCase()).list();

6.Hibernate提供了org.hibernate.criterion.Projection接口和org.hibernate.criterion.Projections类来支持Criteria投影

http://www.blogjava.net/weibogao/archive/2008/04/26/56749.html

List list = session
        .createCriteria(Emp.class)
        .setProjection(
                Projections.projectionList()
                        .add(Property.forName("empName"))
                        .add(Property.forName("hiredate")))
       .list();

List list = session.createCriteria(Dept.class)
        .setProjection(Property.forName("deptName")).list();

7.在Criteria中使用投影来实现分组统计功能

org.hibernate.criterion.Projections类提供了使用聚合函数查询的方法

groupProperty() 分组
rowCount( ) 统计记录数
avg() 统计平均值

8.DetachedCriteria

DetachedCriteria和Criteria功能类似，它实现了CriteriaSpecification接口

Criteria是由Session对象创建的

DetachedCriteria创建时不需要Session对象

使用DetachedCriteria来构造查询条件

可以把DetachedCriteria作为方法参数传递给业务层

DetachedCriteria detachedCriteria = DetachedCriteria
        .forClass(Emp.class, "e")
        .createAlias("e.dept", "d")
        .add(Restrictions.eq("d.deptName", "财务部"))
        .add(Restrictions.ilike("e.empName", "a",
                MatchMode.ANYWHERE));
List list = detachedCriteria.getExecutableCriteria(session)
        .list();

DetachedCriteria avgSalary = DetachedCriteria.forClass(Emp.class,
        "e").setProjection(Property.forName("salary").avg());
List list = session.createCriteria(Emp.class)
        .add(Property.forName("salary").gt(avgSalary)).list();

================Criteria分页加动态查询方法======================================
public PageInfo select(Auction condition, int pageIndex){

DetachedCriteria dc = DetachedCriteria.forClass(Auction.class);
Criteria c = session.createCriteria(Auction.class);//建立一次查询
Criteria c1 = session.createCriteria(Auction.class);//建立一次查询

c.addOrder(Order.desc("auctionstarttime"));//添加查询条件-----------注意非空处理----------排序
c.add(Restrictions.ge("auctionstartprice",condition.getAuctionstartprice()));----------比较大小
c.add(Restrictions.ilike("auctiondesc", condition.getAuctiondesc(),MatchMode.ANYWHERE));----------模糊查询

Set settype=new HashSet();c.add(Restrictions.in( "movId",settype)); //--------编号在集合数组中

PageInfo pageInfo = new PageInfo();//实例分页方法
int count = (Integer) c1.setProjection(Projections.rowCount()).uniqueResult();//得到总条数
pageInfo.setCount(count);//设置总条数
pageInfo.setPageIndex(pageIndex);//设置当前页码
c.setMaxResults(PageInfo.PAGESIZE);//设置每次的查询数量
c.setFirstResult((pageIndex - 1) * PageInfo.PAGESIZE);//设置起始条数
List list = c.list();
pageInfo.setPageList(list);//将查询的结果付给查询的实体类
}
===============================分页实体类======================================
public class PageInfo { //利用泛型声明一个分页的实体类
public static final int PAGESIZE = 10;
private Integer count;// 总记录数
private List pageList;// 当前页的记录集合
private Integer pageIndex;// 当前页号
private Integer totalPages;// 总页数

public Integer getTotalPages() {//特殊方法，通过总条数和每页的条数得到页数
this.totalPages = this.count / this.PAGESIZE;
if (this.count % this.PAGESIZE != 0)
this.totalPages++;
return this.totalPages;
}
}
===============================分页关于时间的处理======================================
---映射文件-------关于时间的处理---------------
         
           
       

---实体类-------关于时间的处理---------------
        private Timestamp auctionstarttime;、

---数据库-------关于时间的处理---------------
        AUCTIONSTARTTIME             TIMESTAMP(6)
---方法内使用-------关于时间的处理---------------
======表单赋值
开始时间

======提取：输入的时间按字符串转化为date,后提取毫秒数，转化为java.sql.Timestamp
           if(request.getParameter("auctionStartTime")!=null&&!"".equals(request.getParameter("auctionStartTime"))){
condition.setAuctionstarttime(new java.sql.Timestamp(Tool.strToDate(request.getParameter("auctionStartTime"), "yyyy-MM-dd HH:mm:dd").getTime()));
}
======底层
     if (condition.getAuctionstarttime() != null) {
c.add(Restrictions.ge("auctionstarttime",
condition.getAuctionstarttime()));
c1.add(Restrictions.ge("auctionstarttime",
condition.getAuctionstarttime()));
}


===============================servlet的调用方法以及获得返回值======================================


int pageIndex=1;//登陆界面进入
if(request.getParameter("pageIndex")!=null){
pageIndex=new Integer(request.getParameter("pageIndex")).intValue();//
}Auction condition=new Auction();

PageInfo auctionPageinfo = biz.find(condition,pageIndex);
request.setAttribute("auctionPageInfo", auctionPageinfo);
request.getRequestDispatcher("auctionList.jsp").forward(request, response);




===============================jsp页面======================================


---------页码显示------------------------------------------------------------------------------
       首页
       
        上一页
            
         当前页：${auctionPageinfo.pageIndex}    
         
       
        ${pageIndex}
         
      
       
        下一页
       
        尾页


------------------

---------动态查询表单------------------------------------------------------------------------------

    名称
   
       描述
       
       开始时间
       
       结束时间
       
       起拍价
   
   
   

---------详细信息显示------------------------------------------------------------------------------
 
     

       
• ${auction.auctionname }

       
• ${auction.auctiondesc }

       
• ${auction.auctionstarttime }

       
• ${auction.auctionendtime }

       
• ${auction.auctionstartprice }

       
• 
          
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