HiSEN

#登陆数据库
hisen@ubuntu:/$ mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.17-0ubuntu0.16.04.2 (Ubuntu)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| employees          |
| log4j              |
| mysql              |
| performance_schema |
| ssm                |
| sys                |
+--------------------+
7 rows in set (0.00 sec)

mysql> use employees
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+----------------------+
| Tables_in_employees  |
+----------------------+
| current_dept_emp     |
| departments          |
| dept_emp             |
| dept_emp_latest_date |
| dept_manager         |
| employees            |
| salaries             |
| titles               |
+----------------------+
8 rows in set (0.00 sec)

mysql> select * from employees limit 10;
+--------+------------+------------+-----------+--------+------------+
| emp_no | birth_date | first_name | last_name | gender | hire_date  |
+--------+------------+------------+-----------+--------+------------+
|  10001 | 1953-09-02 | Georgi     | Facello   | M      | 1986-06-26 |
|  10002 | 1964-06-02 | Bezalel    | Simmel    | F      | 1985-11-21 |
|  10003 | 1959-12-03 | Parto      | Bamford   | M      | 1986-08-28 |
|  10004 | 1954-05-01 | Chirstian  | Koblick   | M      | 1986-12-01 |
|  10005 | 1955-01-21 | Kyoichi    | Maliniak  | M      | 1989-09-12 |
|  10006 | 1953-04-20 | Anneke     | Preusig   | F      | 1989-06-02 |
|  10007 | 1957-05-23 | Tzvetan    | Zielinski | F      | 1989-02-10 |
|  10008 | 1958-02-19 | Saniya     | Kalloufi  | M      | 1994-09-15 |
|  10009 | 1952-04-19 | Sumant     | Peac      | F      | 1985-02-18 |
|  10010 | 1963-06-01 | Duangkaew  | Piveteau  | F      | 1989-08-24 |
+--------+------------+------------+-----------+--------+------------+
10 rows in set (0.00 sec)
#统计各部门曾经拥有的员工数量
mysql> select dept_no,count(*) emp_sum
    -> from dept_emp
    -> group by dept_no
    -> order by emp_sum desc;
+---------+---------+
| dept_no | emp_sum |
+---------+---------+
| d005    |   85707 |
| d004    |   73485 |
| d007    |   52245 |
| d009    |   23580 |
| d008    |   21126 |
| d001    |   20211 |
| d006    |   20117 |
| d003    |   17786 |
| d002    |   17346 |
+---------+---------+
9 rows in set (0.63 sec)
#创建视图
mysql> CREATE VIEW test AS
    -> SELECT dept_no, COUNT(*) AS emp_sum
    -> FROM dept_emp
    -> GROUP BY dept_no
    -> ORDER BY emp_sum DESC
    -> ;
Query OK, 0 rows affected (0.16 sec)
mysql> select * from test;
+---------+---------+
| dept_no | emp_sum |
+---------+---------+
| d005    |   85707 |
| d004    |   73485 |
| d007    |   52245 |
| d009    |   23580 |
| d008    |   21126 |
| d001    |   20211 |
| d006    |   20117 |
| d003    |   17786 |
| d002    |   17346 |
+---------+---------+
9 rows in set (0.11 sec)
#联合查询，加上部门名称
mysql> select test.dept_no,emp_sum,dept_name
    -> from test,departments
    -> where test.dept_no = departments.dept_no;
+---------+---------+--------------------+
| dept_no | emp_sum | dept_name          |
+---------+---------+--------------------+
| d009    |   23580 | Customer Service   |
| d005    |   85707 | Development        |
| d002    |   17346 | Finance            |
| d003    |   17786 | Human Resources    |
| d001    |   20211 | Marketing          |
| d004    |   73485 | Production         |
| d006    |   20117 | Quality Management |
| d008    |   21126 | Research           |
| d007    |   52245 | Sales              |
+---------+---------+--------------------+
9 rows in set (0.16 sec)

cat filename | tail -n +3000 | head -n 1000

cat filename| head -n 3000 | tail -n +1000

cat -n textfile1 > textfile2

cat -b textfile1 textfile2 >> textfile3

cat /dev/null > /etc/test.txt

npm install hexo-generator-searchdb --save

npm install hexo-generator-searchdb --save

#Shift + Home选中当前光标到行首
#Shift + End选中当前光标到行尾
#Shift + ↑/↓/←/→ 移动光标并且选中
#Alt + X 执行选中的sql
#Ctrl + Enter 执行当前光标所在行的sql
#Ctrl + Alt + F 格式化SQL（file -> properties -> +SQL Editor -> SQL formatting）

hisen@ubuntu:/var/lib$ su
Password: 
su: Authentication failure

hisen@ubuntu:$ sudo passwd root
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully
hisen@ubuntu:$ su
Password: 
root@ubuntu:# cd mysql

package com.hisen.json;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

/**
 * Created by hisenyuan on 2017/3/23 at 18:02.
 */
public class test {
    public static void main(String[] args) {String s = "{'A':'a'}";
        JSONObject obj= JSON.parseObject(s);
        System.out.println(obj.get("A"));
    }
}

package com.hisen.json;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

/**
 * Created by hisenyuan on 2017/3/23 at 18:02.
 */
public class test {

  public static void main(String[] args) {
    String s = "{'A':'a'}";
    JSONObject obj = JSON.parseObject(s);
    System.out.println(obj.get("A"));
  }
}

\HOME\IntelliJ IDEA 2016.3.4\bin\idea64.exe.vmoptions

File -> Settings -> Build, Execution, Deployment
-> Compiler -> Java Compiler -> Addition command line parameters

File -> Settings -> Editor -> File Encodings

Run/debug Configuration tomcat

Application Server was not connected before run configuration stop, 
reason: Unable to ping server at localhost:1099

Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
Unrecognized option: -URIEncoding=UTF-8