String hql = "select new map(name,price) from Commodity";
Query query = session.createQuery(hql);
List
List,Set 集合的方法与基本方法中返回List
select 只查询一个字段的情况
如果你在select中只查询一个字段,那么query.list()返回的就是List
String hql = "select name from Commodity";
Query query = session.createQuery(hql);
List commodities = query.list();
for(Object commodity : commodities){
System.out.println(commodity.toString());
}
distinct 过滤重复数据
熟悉sql语句的同学都应该认识这个,过滤掉多余的重复记录只保留一条
String hql = "select distinct c.sex from Customer c ";
Query query = session.createQuery(hql);
List list = query.list();
for(Object obj : list){
System.out.println(obj);
}
where 条件查询
跟sql语法一模一样
比较运算符 >大于 , < 小于 , >= 大于等于, <= 小于等于, <>不等于, = 等于, is null, is not null
查询女客户
String hql = " from Customer c where c.sex<>'男'";
Query query = session .createQuery(hql);
List customers = query.list();
for(Customer c : customers){
System.out.println("name:"+c.getName());
System.out.println("sex:"+c.getSex());
}
in,between
查询年龄是20或者40的顾客
String hql = " from Customer c where c.age not in(20,40) ";
Query query = session.createQuery(hql);
List customers = query.list();
for(Customer c: customers){
System.out.println("name:"+c.getName());
System.out.println("age:"+c.getAge());
}
查询年龄在20到40岁的客户
String hql = " from Customer c where c.age not between 20 and 40 ";
Query query = session.createQuery(hql);
List customers = query.list();
for(Customer c: customers){
System.out.println("name:"+c.getName());
System.out.println("age:"+c.getAge());
}
like 模糊查询
String hql = " from Customer c where c.address like '%北京%'";
Query query = session.createQuery(hql);
List customers = query.list();
for(Customer c : customers){
System.out.println("name:"+c.getName());
System.out.println("address :"+ c.getAddress());
}
1,java读取.properties配置文件
InputStream in;
try {
in = test.class.getClassLoader().getResourceAsStream("config/ipnetOracle.properties");//配置文件的路径
Properties p = new Properties()
create or replace procedure proc_test01
as
type emp_row is record(
empno emp.empno%type,
ename emp.ename%type,
job emp.job%type,
mgr emp.mgr%type,
hiberdate emp.hiredate%type,
sal emp.sal%t
今天在执行一个脚本时,本来是想在脚本中启动hdfs和hive等程序,可以在执行到service hive-server start等启动服务的命令时会报错,最终解决方法记录一下:
脚本报错如下:
./olap_quick_intall.sh: line 57: service: command not found
./olap_quick_intall.sh: line 59
最近重新安装的电脑,配置了新环境,老是出现:
adb server is out of date. killing...
ADB server didn't ACK
* failed to start daemon *
百度了一下,说是端口被占用,我开个eclipse,然后打开cmd,就提示这个,很烦人。
一个比较彻底的解决办法就是修改
import java.util.HashMap;
public class Title {
public static void main(String[] args){
f();
}
// 二位数组的应用
//12、二维数组中,哪一行或哪一列的连续存放的0的个数最多,是几个0。注意,是“连续”。
public static void f(){