1、HQL（Hibernate Query language）
hibernate query language: the main object-oriented thinking to write SQl statement, hibernate query form
1.1, all inquiries:
From order // order is the name of the object is not a table
//查询所有
public void findAll(){
//得到seesion
Session session = YtUserUtils.openSession();
String hql = "from UserinfoEntity"; //找对象 不是表
//createQuery 前面是hql，后面是指向要查询的内容
Query <UserinfoEntity> query = session.createQuery(hql, UserinfoEntity.class);
//拿到结果集
List <UserinfoEntity> resultList = query.getResultList();
//遍历结果集，输出
for (UserinfoEntity userinfoEntity:resultList) {
System.out.println(userinfoEntity.getUid() + "\t" + userinfoEntity.getUserName() + "\t" + userinfoEntity.getUserPass());
}
//关闭session
session.close();
}Alias query: String HQL = "UserInfoEntity from the SELECT ue ue";
1.2, paging query:
//分页查询
public void findByPage(int start,int size){
//得到seesion
Session session = YtUserUtils.openSession();
String hql = "from UserinfoEntity"; //找对象 不是表
//createQuery 前面是hql，后面是指向要查询的内容
Query <UserinfoEntity> query = session.createQuery(hql, UserinfoEntity.class);
//设置起始位置
query.setFirstResult(start); //从0开始
//设置每次取多少条记录
query.setMaxResults(size);
//拿到结果集
List <UserinfoEntity> resultList = query.getResultList();
//遍历结果集，输出
for (UserinfoEntity userinfoEntity:resultList) {
System.out.println(userinfoEntity.getUid() + "\t" + userinfoEntity.getUserName() + "\t" + userinfoEntity.getUserPass());
}
//关闭session
session.close();
}1.3, query :( conditions index placeholder)
//条件查询（索引占位符）
public void findByIdHql(Integer uid){
//得到session
Session session = YtUserUtils.openSession();
//hql
String hql = "from UserinfoEntity where uid = ?";
Query <UserinfoEntity> query = session.createQuery(hql, UserinfoEntity.class);
//设置参数值
query.setParameter(0,uid);
//获取单个对象
UserinfoEntity userinfoEntity = query.uniqueResult();
System.out.println(userinfoEntity.getUid() + "\t" + userinfoEntity.getUserName() + "\t" + userinfoEntity.getUserPass());
//关闭链接
session.close();
}1.4, condition query :( named placeholders)
//条件查询（命名占位符）
public void findByIdHqlByName(Integer uid){
//得到session
Session session = YtUserUtils.openSession();
//hql
String hql = "from UserinfoEntity where uid =:uid";
Query <UserinfoEntity> query = session.createQuery(hql, UserinfoEntity.class);
//设置参数值
query.setParameter("uid",uid);
//获取单个对象
UserinfoEntity userinfoEntity = query.uniqueResult();
System.out.println(userinfoEntity.getUid() + "\t" + userinfoEntity.getUserName() + "\t" + userinfoEntity.getUserPass());
//关闭链接
session.close();
}
