本文详细介绍了使用HQL语句进行数据库操作的各种方法，包括查询整个映射对象所有字段、查询指定字段、修改查询结果形式、条件查询以及更新数据等。通过实例演示了如何灵活运用HQL进行复杂查询，包括使用参数、自定义索引名、设置属性值等方式来执行条件查询，并展示了如何将查询结果以不同形式展示，如列表、Map或自定义类型。同时，还涉及了数据库更新操作及如何通过SQL语句执行更复杂的数据库命令。
1. 查询整个映射对象所有字段
//直接from查询出来的是一个映射对象，即：查询整个映射对象所有字段
String hql =
"from Users"
;
Query query = session.createQuery(hql);
List<Users> users = query.list();
for
(Users user : users){
System.out.println(user.getName() +
" : "
+ user.getPasswd() +
" : "
+ user.getId());
}
输出结果为：
name1 : password1 :
1
name2 : password2 :
2
name3 : password3 :
3
|
2.查询字段
//查询其中几个字段
String hql =
" select name,passwd from Users"
;
Query query = session.createQuery(hql);
//默认查询出来的list里存放的是一个Object数组
List<Object[]> list = query.list();
for
(Object[] object : list){
String name = (String)object[
0
];
String passwd = (String)object[
1
];
System.out.println(name +
" : "
+ passwd);
}
输出结果为：
name1 : password1
name2 : password2
name3 : password3
|
3.修改默认查询结果(query.list())不以Object[]数组形式返回，以List形式返回
//查询其中几个字段,添加new list(),注意list里的l是小写的。也不需要导入包，这样通过query.list()出来的list里存放的不再是默认的Object数组了，而是List集合了
String hql =
" select new list(name,passwd) from Users"
;
Query query = session.createQuery(hql);
//默认查询出来的list里存放的是一个Object数组，但是在这里list里存放的不再是默认的Object数组了，而是List集合了
List<List> list = query.list();
for
(List user : list){
String name = (String)user.get(
0
);
String passwd = (String)user.get(
1
);
System.out.println(name +
" : "
+ passwd);
}
/**
输出结果为：
name1 : password1
name2 : password2
name3 : password3
*/
|
4.修改默认查询结果(query.list())不以Object[]数组形式返回，以Map形式返回
//查询其中几个字段,添加new map(),注意map里的m是小写的。也不需要导入包，这样通过query.list()出来的list里存放的不再是默认的Object数组了，而是map集合了
String hql =
" select new map(name,passwd) from Users"
;
Query query = session.createQuery(hql);
//默认查询出来的list里存放的是一个Object数组，但是在这里list里存放的不再是默认的Object数组了，而是Map集合了
List<Map> list = query.list();
for
(Map user : list){
//一条记录里所有的字段值都是map里的一个元素,key是字符串0,1,2,3....，value是字段值
//如果将hql改为：String hql = " select new map(name as username,passwd as password) from Users";,那么key将不是字符串0,1,2...了，而是"username","password"了
String name = (String)user.get(
"0"
);
//get("0");是get(key),注意:0,1,2...是字符串，而不是整形
String passwd = (String)user.get(
"1"
);
System.out.println(name +
" : "
+ passwd);
}
/**
输出结果为：
name1 : password1
name2 : password2
name3 : password3
*/
|
5.修改默认查询结果(query.list())不以Object[]数组形式返回，以自定义类型返回
6.条件查询
//条件查询，参数索引值从0开始，索引位置。通过setString,setParameter设置参数
String hql =
"from Users where name=? and passwd=?"
;
Query query = session.createQuery(hql);
//第1种方式
// query.setString(0, "name1");
// query.setString(1, "password1");
//第2种方式
query.setParameter(
0
,
"name1"
,Hibernate.STRING);
query.setParameter(
1
,
"password1"
,Hibernate.STRING);
List<Users> list = query.list();
for
(Users users : list){
System.out.println(users.getId());
}
|
//条件查询，自定义索引名(参数名):username,:password.通过setString,setParameter设置参数
String hql =
"from Users where name=:username and passwd=:password"
;
Query query = session.createQuery(hql);
//第1种方式
// query.setString("username", "name1");
// query.setString("password", "password1");
//第2种方式,第3个参数确定类型
query.setParameter(
"username"
,
"name1"
,Hibernate.STRING);
query.setParameter(
"password"
,
"password1"
,Hibernate.STRING);
List<Users> list = query.list();
for
(Users users : list){
System.out.println(users.getId());
}
|
//条件查询,通过setProperties设置参数
String hql =
"from Users where name=:username and passwd=:password"
;
Query query = session.createQuery(hql);
//MyUser类的2个属性必须和:username和:password对应
MyUser myUser =
new
MyUser(
"name1"
,
"password1"
);
query.setProperties(myUser);
List<Users> list = query.list();
for
(Users users : list){
System.out.println(users.getId());
}
|
7.update 数据
执行SQL语句（为什么要用SQL语句，我想是为了执行某些复杂的SQL语句吧）
String sql=
"update Table set field = 'test'"
Session session = HibernateSessionFactory.getSession();
session.createSQLQuery(sql).executeUpdate();
ts.commit();
|
执行HQL语句
String hql=
"update Table set field = 'test'"
|
Session session = HiberanteSessionFactory.getSession();
Transaction ts = session.beginTransaction();
Query query = session.createQuery(hql);
query.executeUpdate();
ts.commit();
*************************************************************************************
/**
*
*/
package com.b510.example;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.hibernate.Criteria;
import org.hibernate.FetchMode;
import org.hibernate.Query;
import org.hibernate.Session;
/**
*
* @author XHW
*
* @date 2011-6-18
*
*/
public class HibernateTest {
/**
* @param args
*/
public static void main(String[] args) {
HibernateTest test = new HibernateTest();
test.where();
test.function();
test.update();
test.jiaoChaCheck();
test.innerJoin();
test.QBC();
test.leftOuterJoin();
test.rightOuterJoin();
}
public void where() {
// 使用where查询
Session session = HibernateSessionFactoryUtil.getSessionFactory()
.openSession();
session.beginTransaction();
Query query = session
.createQuery("from User where id not between 200 and 2000");
List<User> list = query.list();
for (User user : list) {
System.out.println(user.getId() + user.getUsername());
}
// 投影查询 中使用where子句
query = session.createQuery("select username from User where id=2");
List<String> listname = query.list();
for (String name : listname) {
System.out.println(name);
}
// in查询
query = session
.createQuery("from User where username in ('Hongten','Hanyuan','dfgd')");
List<User> listin = query.list();
for (User user : listin) {
System.out.println(user.getId() + user.getUsername());
}
// like查询
query = session.createQuery("from User where username not like 'Hon%'");
List<User> listlike = query.list();
for (User user : listlike) {
System.out.println(user.getId() + user.getUsername());
}
// null查询
query = session.createQuery("from User where password is null");
List<User> listnull = query.list();
for (User user : listnull) {
System.out.println(user.getId() + user.getUsername());
}
// and查询
query = session
.createQuery("from User where password is not null and id<5");
List<User> listand = query.list();
for (User user : listand) {
System.out.println(user.getId() + user.getUsername()
+ user.getPassword());
}
// order by
query = session.createQuery("from User order by username,id desc");
List<User> listorderby = query.list();
for (User user : listorderby) {
System.out.println(user.getId() + user.getUsername());
}
// 使用"?"号 作为参数占位符，一条HQL语句中可以使用多个？
// query.setInteger(0,2)
// query.setString(0,"Hongten")
query = session
.createQuery("select username from User where username=?");
query.setString(0, "Hongten");
List<String> listwenhao = query.list();
for (String name : listwenhao) {
System.out.println(name);
}
session.getTransaction().commit();
}
public void function() {// 把大写字母转化为小写字母
// 作用可以用在：比如在一个用户注册的程序中，大小写不容易区分，但是全部转化为小写后就可以很容易进行比较
Session session = HibernateSessionFactoryUtil.getSessionFactory()
.openSession();
session.beginTransaction();
// 输出原始的数据
Query query = session.createQuery("select username from User");
List<String> list = query.list();
for (String name : list) {
System.out.println(name);
}
System.out.println("-------------------------------------------");
// 输出的数据全部转化为小写
query = session.createQuery("select lower(username) from User");
List<String> listChange = query.list();
for (String name : listChange) {
System.out.println(name);
}
session.getTransaction().commit();
}
public void update() {
Session session = HibernateSessionFactoryUtil.getSessionFactory()
.openSession();
session.beginTransaction();
Query query = session
.createQuery("update User set username='洪伟1231' where id=?");
query.setInteger(0, 3);
int rowCount = query.executeUpdate();
System.out.println(rowCount);
session.getTransaction().commit();
}
public void operateProfile() {// 对profile这个类执行HQL语句操作
Session session = HibernateSessionFactoryUtil.getSessionFactory()
.openSession();
session.beginTransaction();
// 执行查询操作
Query query = session.createQuery("from Profile");
List<Profile> list = query.list();
for (Profile profile : list) {
System.out.println(profile.getId() + profile.getEmail()
+ profile.getAddress() + profile.getMobile()
+ profile.getPostcode());
}
// 执行删除操作
query = session.createQuery("delete from Profile where id=?");
query.setInteger(0, 3);
int rowCount = query.executeUpdate();
System.out.println(rowCount);
session.getTransaction().commit();
}
public void jiaoChaCheck() {//交叉查询
//这种方法查询出来的结果是笛卡尔积，对于我们开发中没有多大用处
Session session = HibernateSessionFactoryUtil.getSessionFactory()
.openSession();
session.beginTransaction();
Query query=session.createQuery("from User,Profile");
List<Object[]> list=query.list();
for(Object[] values:list){
User user=(User)values[0];
System.out.print("ID :"+user.getId()+",UserName:"+user.getUsername()+",Password:"+user.getPassword());
Profile profile=(Profile)values[1];
System.out.println(profile.getEmail()+profile.getMobile()+profile.getAddress()+profile.getPostcode());
}
session.getTransaction().commit();
}
public void innerJoin(){//内连接查询
/**
* 下面三种hql语句都是可以得到相同的结果
* String hql="select p from Profile as p inner join p.user";
* 在下面的hql语句中加入"fetch"后，此hql语句变为了"迫切HQL"语句，这样的查询效率要比上面的hql语句要高
* String hql="select p from Profile as p inner join fetch p.user";
*
* String hql="select p from Profile p,User u where p.user=u";
* String hql="select p from Profile p,User u where p.user.id=u.id";
*
*/
Session session = HibernateSessionFactoryUtil.getSessionFactory()
.openSession();
session.beginTransaction();
String hql="select p from Profile as p inner join fetch p.user";
//String hql="select p from Profile p,User u where p.user=u";
//String hql="select p from Profile p,User u where p.user.id=u.id";
Query query=session.createQuery(hql);
List<Profile> list=query.list();
for(Profile p:list){
System.out.println("ID:"+p.getUser().getId()+" Username: "+p.getUser().getUsername()+" Email: "+p.getEmail()+", Address: "+p.getAddress());
}
session.getTransaction().commit();
}
public void QBC(){//QBC中实现内连接查询
Session session=HibernateSessionFactoryUtil.getSessionFactory().openSession();
session.beginTransaction();
Criteria criteria=session.createCriteria(Profile.class).createCriteria("user");
List<Profile> list=criteria.list();
for(Profile p:list){
System.out.println("ID:"+p.getUser().getId()+" Username: "+p.getUser().getUsername()+" Email: "+p.getEmail()+", Address: "+p.getAddress());
}
//QBC中实现外连接
System.out.println("##################################################");
criteria=session.createCriteria(Profile.class).setFetchMode("user", FetchMode.JOIN);
List<Profile> listp=criteria.list();
for(Profile p:list){
System.out.println("ID:"+p.getUser().getId()+" Username: "+p.getUser().getUsername()+" Email: "+p.getEmail()+", Address: "+p.getAddress());
}
session.getTransaction().commit();
}
public void leftOuterJoin(){//左外连接
/**
* String hql="select p from Profile p left outer join p.user order by p.user.id";
* 在下面的hql语句中加入"fetch"后，此hql语句变为了"迫切HQL"语句，这样的查询效率要比上面的hql语句要高
* String hql="select p from Profile p left outer join fetch p.user order by p.user.id";
*
* String hqlu="select u from User u left outer join u.profiles";
* 在下面的hql语句中加入"fetch"后，此hql语句变为了"迫切HQL"语句，这样的查询效率要比上面的hql语句要高
* String hqlu="select u from User u left outer join fetch u.profiles";
*/
Session session=HibernateSessionFactoryUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
String hql="select p from Profile p left outer join fetch p.user order by p.user.id";
Query query=session.createQuery(hql);
List<Profile> list=query.list();
for(Profile p:list){
System.out.println("ID:"+p.getUser().getId()+" Username: "+p.getUser().getUsername()+" Email: "+p.getEmail()+", Address: "+p.getAddress());
}
System.out.println("-------------------------------------");
String hqlu="select u from User u left outer join fetch u.profiles";
query=session.createQuery(hqlu);
List<User> listu=query.list();
for(User u:listu){
System.out.println(u.getId()+u.getUsername()+u.getProfiles());
}
session.getTransaction().commit();
}
public void rightOuterJoin(){//右外连接
Session session=HibernateSessionFactoryUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
String hql="select u from User u right outer join u.profiles order by u.id";
Query query=session.createQuery(hql);
List<User> listu=query.list();
for(User user:listu){
System.out.println(user.getId()+user.getUsername()+user.getProfiles());
}
session.getTransaction().commit();
}
}
结果：
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).log4j:WARN Please initialize the log4j system properly.
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
where
user0_.id not between 200 and 2000
1hongten
2hanyuan
3hongwei
4mingliu
5shouzhang
Hibernate:
select
user0_.username as col_0_0_
from
users.user user0_
where
user0_.id=2
hanyuan
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
where
user0_.username in (
'Hongten' , 'Hanyuan' , 'dfgd'
)
1hongten
2hanyuan
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
where
user0_.username not like 'Hon%'
2hanyuan
4mingliu
5shouzhang
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
where
user0_.password is null
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
where
(
user0_.password is not null
)
and user0_.id<5
1hongten123
2hanyuan5645645
3hongwei5645645
4mingliu5645645
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
order by
user0_.username,
user0_.id desc
2hanyuan
1hongten
3hongwei
4mingliu
5shouzhang
Hibernate:
select
user0_.username as col_0_0_
from
users.user user0_
where
user0_.username=?
hongten
Hibernate:
select
user0_.username as col_0_0_
from
users.user user0_
hongten
hanyuan
hongwei
mingliu
shouzhang
-------------------------------------------
Hibernate:
select
lower(user0_.username) as col_0_0_
from
users.user user0_
hongten
hanyuan
hongwei
mingliu
shouzhang
Hibernate:
update
users.user
set
username='Hongwei1231'
where
id=?
1
Hibernate:
select
user0_.id as id0_0_,
profile1_.id as id1_1_,
user0_.username as username0_0_,
user0_.password as password0_0_,
profile1_.user_id as user2_1_1_,
profile1_.email as email1_1_,
profile1_.phone as phone1_1_,
profile1_.mobile as mobile1_1_,
profile1_.address as address1_1_,
profile1_.postcode as postcode1_1_
from
users.user user0_,
users.profile profile1_
ID :1,UserName:hongten,Password:123hongtenzone@foxmail.com45464Guangzhoushi65465
ID :1,UserName:hongten,Password:123hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :1,UserName:hongten,Password:123hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :2,UserName:hanyuan,Password:5645645hongtenzone@foxmail.com45464Guangzhoushi65465
ID :2,UserName:hanyuan,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :2,UserName:hanyuan,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :3,UserName:Hongwei1231,Password:5645645hongtenzone@foxmail.com45464Guangzhoushi65465
ID :3,UserName:Hongwei1231,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :3,UserName:Hongwei1231,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :4,UserName:mingliu,Password:5645645hongtenzone@foxmail.com45464Guangzhoushi65465
ID :4,UserName:mingliu,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :4,UserName:mingliu,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :5,UserName:shouzhang,Password:5645645hongtenzone@foxmail.com45464Guangzhoushi65465
ID :5,UserName:shouzhang,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
ID :5,UserName:shouzhang,Password:5645645hanyuan@foxmail.com45648255GuangzhoushiDianbian65465
Hibernate:
select
profile0_.id as id1_0_,
user1_.id as id0_1_,
profile0_.user_id as user2_1_0_,
profile0_.email as email1_0_,
profile0_.phone as phone1_0_,
profile0_.mobile as mobile1_0_,
profile0_.address as address1_0_,
profile0_.postcode as postcode1_0_,
user1_.username as username0_1_,
user1_.password as password0_1_
from
users.profile profile0_
inner join
users.user user1_
on profile0_.user_id=user1_.id
ID:1 Username: hongten Email: hongtenzone@foxmail.com, Address: Guangzhoushi
ID:2 Username: hanyuan Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
ID:3 Username:Hongwei1231 Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
Hibernate:
select
this_.id as id1_1_,
this_.user_id as user2_1_1_,
this_.email as email1_1_,
this_.phone as phone1_1_,
this_.mobile as mobile1_1_,
this_.address as address1_1_,
this_.postcode as postcode1_1_,
user1_.id as id0_0_,
user1_.username as username0_0_,
user1_.password as password0_0_
from
users.profile this_
inner join
users.user user1_
on this_.user_id=user1_.id
ID:1 Username: hongten Email: hongtenzone@foxmail.com, Address: Guangzhoushi
ID:2 Username: hanyuan Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
ID:3 Username: Hongwei1231 Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
##################################################
Hibernate:
select
this_.id as id1_1_,
this_.user_id as user2_1_1_,
this_.email as email1_1_,
this_.phone as phone1_1_,
this_.mobile as mobile1_1_,
this_.address as address1_1_,
this_.postcode as postcode1_1_,
user2_.id as id0_0_,
user2_.username as username0_0_,
user2_.password as password0_0_
from
users.profile this_
left outer join
users.user user2_
on this_.user_id=user2_.id
ID:1 Username: hongten Email: hongtenzone@foxmail.com, Address: Guangzhoushi
ID:2 Username: hanyuan Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
ID:3 Username: 洪伟1231 Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
Hibernate:
select
profile0_.id as id1_0_,
user1_.id as id0_1_,
profile0_.user_id as user2_1_0_,
profile0_.email as email1_0_,
profile0_.phone as phone1_0_,
profile0_.mobile as mobile1_0_,
profile0_.address as address1_0_,
profile0_.postcode as postcode1_0_,
user1_.username as username0_1_,
user1_.password as password0_1_
from
users.profile profile0_
left outer join
users.user user1_
on profile0_.user_id=user1_.id
order by
profile0_.user_id
ID:1 Username: hongten Email: hongtenzone@foxmail.com, Address: Guangzhoushi
ID:2 Username: hanyuan Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
ID:3 Username: 洪伟1231 Email: hanyuan@foxmail.com, Address: GuangzhoushiDianbian
-------------------------------------
Hibernate:
select
user0_.id as id0_0_,
profiles1_.id as id1_1_,
user0_.username as username0_0_,
user0_.password as password0_0_,
profiles1_.user_id as user2_1_1_,
profiles1_.email as email1_1_,
profiles1_.phone as phone1_1_,
profiles1_.mobile as mobile1_1_,
profiles1_.address as address1_1_,
profiles1_.postcode as postcode1_1_,
profiles1_.user_id as user2_0__,
profiles1_.id as id0__
from
users.user user0_
left outer join
users.profile profiles1_
on user0_.id=profiles1_.user_id
1hongten[com.b510.example.Profile@14eaec9]
2hanyuan[com.b510.example.Profile@569c60]
3Hongwei1231[com.b510.example.Profile@d67067]
4mingliu[]
5shouzhang[]
Hibernate:
select
user0_.id as id0_,
user0_.username as username0_,
user0_.password as password0_
from
users.user user0_
right outer join
users.profile profiles1_
on user0_.id=profiles1_.user_id
order by
user0_.id
Hibernate:
select
profiles0_.user_id as user2_1_,
profiles0_.id as id1_,
profiles0_.id as id1_0_,
profiles0_.user_id as user2_1_0_,
profiles0_.email as email1_0_,
profiles0_.phone as phone1_0_,
profiles0_.mobile as mobile1_0_,
profiles0_.address as address1_0_,
profiles0_.postcode as postcode1_0_
from
users.profile profiles0_
where
profiles0_.user_id=?
1hongten[com.b510.example.Profile@10c0f66]
Hibernate:
select
profiles0_.user_id as user2_1_,
profiles0_.id as id1_,
profiles0_.id as id1_0_,
profiles0_.user_id as user2_1_0_,
profiles0_.email as email1_0_,
profiles0_.phone as phone1_0_,
profiles0_.mobile as mobile1_0_,
profiles0_.address as address1_0_,
profiles0_.postcode as postcode1_0_
from
users.profile profiles0_
where
profiles0_.user_id=?
2hanyuan[com.b510.example.Profile@e265d0]
Hibernate:
select
profiles0_.user_id as user2_1_,
profiles0_.id as id1_,
profiles0_.id as id1_0_,
profiles0_.user_id as user2_1_0_,
profiles0_.email as email1_0_,
profiles0_.phone as phone1_0_,
profiles0_.mobile as mobile1_0_,
profiles0_.address as address1_0_,
profiles0_.postcode as postcode1_0_
from
users.profile profiles0_
where
profiles0_.user_id=?
3Hongwei1231[com.b510.example.Profile@8997d1]
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