对天乙社区bbscs8实现的详细分析三

此文为转载：http://www.diybl.com/course/1_web/webjs/2007113/82989.html

OK!我们直接进入DAO层:先看接口,发现与service接口层的方法并不相同,主要是由于service层有些方法是业务处理用,而不是用于数据处理,如createBoard,updateBoard,findBoardsAllTree,getBoardPermission,getBoardMasterPermission,isBoardMaster,当然DAO接口层也有一些方法是没有的:findBoardsNeedCount,findBoardsInIDsfindBoardsIdByParentIDInUse等等,我们看其实现吧:
进入com.laoer.bbscs.BoardHibernateDAO中首先是一些字符常量:
private static final String LOADS_BY_PARENTID_BY_ORDER = "from Board where parentID = ? order by orders";
private static final String LOADS_ALL = "from Board";
public static final String[] FIND_BOARDS = new String[3];
public static final String LOAD_NEXT_ORDER = "select max(orders) from Board where parentID = ?";
private static final String LOAD_IDS_IN_USE = "select id from Board where parentID = ? and useStat = 1";
我们看几个重点的实现方法:
public List findBoardsByParentID(long pid) {
return this.getHibernateTemplate().find(LOADS_BY_PARENTID_BY_ORDER, new Long(pid));
}
其重载方法:
public List findBoardsByParentID(final long pid, final int useStat, final int hidden, final int orderType) {
return getHibernateTemplate().executeFind(new HibernateCallback() {
public Object doInHibernate(Session s) throws HibernateException {
Criteria c = s.createCriteria(Board.class);
c.add(Restrictions.eq("parentID", new Long(pid)));
if (useStat != -1) {
c.add(Restrictions.eq("useStat", new Integer(useStat)));
}
if (hidden != -1) {
c.add(Restrictions.eq("isHidden", new Integer(hidden)));
}
if (orderType != -1) {
if (orderType == Constant.FIND_BOARDS_BY_ORDER) {
c.addOrder(Order.asc("orders"));
}
if (orderType == Constant.FIND_BOARDS_BY_MAINPOSTNUM) {
c.addOrder(Order.desc("mainPostNum"));
}
if (orderType == Constant.FIND_BOARDS_BY_POSTNUM) {
c.addOrder(Order.desc("postNum"));
}
}

return c.list();
}
});
}
其中用到了条件查询(Criteria Query),参考http://blog.sina.com.cn/u/4a5e7dc401000878 和http://hi.baidu.com/yaolihui/blog/item/7c77b58286a56792f703a663.html,而public List findBoardIdsByParentID(final long pid, final int useStat, final int hidden, final int orderType)采用了构造HQL语句的方式来完成查询!根据parentID预取得Board序列:
public int getNextOrder(long pid) {
List l = getHibernateTemplate().find(LOAD_NEXT_ORDER, new Long(pid));
if (l != null && !l.isEmpty()) {
if (l.get(0) == null) {
return 5;
} else {
return ((Integer) l.get(0)).intValue() + 5;
}
} else {
return 5;
}
}
public int getPostSumNum(final int mainorall, final int useStat, final int hidden) {
int sum = 0;

List list = getHibernateTemplate().executeFind(new HibernateCallback() {
public Object doInHibernate(Session s) throws HibernateException {
Criteria c = s.createCriteria(Board.class);
if (mainorall == 0) {
c.setProjection(Projections.projectionList().add(Projections.sum("mainPostNum"))); //求mainPostNum的和为结果
}
if (mainorall == 1) {
c.setProjection(Projections.projectionList().add(Projections.sum("postNum")));//求postNum的和为结果
}
if (useStat != -1) {
c.add(Restrictions.eq("useStat", new Integer(useStat)));
}
if (hidden != -1) {
c.add(Restrictions.eq("isHidden", new Integer(hidden)));
}
return c.list();
}
});
if (!list.isEmpty()) {
Object obj = (Object) list.get(0);//注:结果集只有一个字段
if (obj != null) {
sum = ((Integer) obj).intValue();
}
}
return sum;
}

public List findBoardsInIDs(final List ids, final int useStat, final int hidden) {
return getHibernateTemplate().executeFind(new HibernateCallback() {
@SuppressWarnings("unchecked")
public Object doInHibernate(Session s) throws HibernateException {
Criteria c = s.createCriteria(Board.class);
if (ids == null) { //ids为空
List idss = new ArrayList();
idss.add(new Long(0));
c.add(Restrictions.in("id", idss));
} else if (ids.isEmpty()) {//ids为empty
ids.add(new Long(0));
c.add(Restrictions.in("id", ids));
} else {
c.add(Restrictions.in("id", ids));//Restrictions.in
}
if (useStat != -1) {
c.add(Restrictions.eq("useStat", new Integer(useStat)));
}
if (hidden != -1) {
c.add(Restrictions.eq("isHidden", new Integer(hidden)));
}
c.addOrder(Order.asc("orders"));
return c.list();
}
});
}

public List findBoardsNeedCount(final int useStat, final int hidden) {
return getHibernateTemplate().executeFind(new HibernateCallback() {
public Object doInHibernate(Session s) throws HibernateException {
Criteria c = s.createCriteria(Board.class);

c.add(Restrictions.or(Restrictions.eq("boardType", new Integer(3)), Restrictions.eq("boardType",
new Integer(4))));//Restrictions.or 3,4的都需要count

if (useStat != -1) {
c.add(Restrictions.eq("useStat", new Integer(useStat)));
}
if (hidden != -1) {
c.add(Restrictions.eq("isHidden", new Integer(hidden)));
}
c.addOrder(Order.desc("mainPostNum"));
c.addOrder(Order.desc("postNum"));
return c.list();
}
});
}

public List findBoardsByParentID(final long pid, final int useStat, final int hidden) {
return getHibernateTemplate().executeFind(new HibernateCallback() {
public Object doInHibernate(Session s) throws HibernateException {
Criteria c = s.createCriteria(Board.class);
c.add(Restrictions.eq("parentID", new Long(pid)));//条件!
if (useStat != -1) {
c.add(Restrictions.eq("useStat", new Integer(useStat)));//附加条件!
}
if (hidden != -1) {
c.add(Restrictions.eq("isHidden", new Integer(hidden)));
}
return c.list();
}
});
}

public List findBoardsIdByParentIDInUse(long pid) {
return this.getHibernateTemplate().find(LOAD_IDS_IN_USE, new Long(pid));
}
OK!分析完毕!当然,对于具体的方法是怎么被用上的,要看web层了.