Reflection mechanism in java
Catalog1. The concept of reflection mechanism2. Base Class of Reflection3. Usage of reflection4. Examples of applications of reflection
Author's introduction: A stack of learning notes, a person working hard
The concept of reflection mechanism:
In the run state, all the properties and methods of this class can be ob ...
Posted by brianlange on Sun, 29 Mar 2020 20:44:53 -0700
1, MySQL database
1. Create database
CREATE DATABASE jdbc CHARACTER SET 'utf8';
2. build tables
CREATE TABLE user (
id int(10) NOT NULL AUTO_INCREMENT,
userName varchar(20) NOT NULL,
PRIMARY KEY (id)
3. Add data
2, Connect MySQL database through JDBC
boolean execute(String SQL): if the ResultSet object can be ...
Posted by katlis on Sun, 29 Mar 2020 11:35:55 -0700
Parameterless stored procedure:
create or replace procedure sayhello
Two call methods of command window
SQL> set serveroutput on; --The first time I have to drive
SQL> exec sayhello
PL/SQL procedure successfully comple ...
Posted by joenjeru on Sun, 29 Mar 2020 09:34:56 -0700
1. PlSql programming procedure language
In the sql statement of database, the common definition of variable condition judgment cycle structure is added to the statement of process 1) . basic grammatical structure
– declaration part
– similar to defining variables
Posted by jayd1985 on Sun, 29 Mar 2020 09:01:48 -0700
The requirements are as follows. There are already generated good spatial data, including date, hour, longitude, latitude, number of people. Use GeoServer to generate heat map.
This article uses the PostgreSQL10 database and has added PostGIS support.
create table table_test(
lon nu ...
Posted by bob1660 on Sun, 29 Mar 2020 08:18:17 -0700
When did Apache Spark start to support the integrated Hive feature? I believe that as long as readers have used Spark, they will say that this is a long time ago.
When does Apache Flink support integration with Hive? Readers may be confused. Haven't they supported it yet, haven't they used it? Or the latest version only supports it, but the fu ...
Posted by elfeste on Fri, 27 Mar 2020 03:09:45 -0700
The original table (order? TBL) is partitioned by dt, and the full order is saved by partition every day
(zone 20200320) ...
Posted by wendu on Thu, 26 Mar 2020 07:10:56 -0700
Recently, when communicating with a big guy, I mentioned the problem of SQL query.
His idea is to query data with the most primitive database driver without ORM. The benefits of doing so are twofold
Express SQL semantics clearly for later optimization. Especially in report, data analysis and other complex SQL.
Reduce useless encapsulation and ...
Posted by Sravan on Tue, 24 Mar 2020 07:29:38 -0700
In enterprise applications, there are too many scenarios involving modifying state. For example, after an enterprise enters the network, it needs to check its qualification. After the individual receives the task, the enterprise administrator shall review the receiver.
In the application management system, usually as shown in the figure below, ...
Posted by Pastulio on Mon, 23 Mar 2020 06:45:23 -0700
In order to facilitate the unified management of exceptions, spring mvc provides controlleradvise annotation to deal with exceptions in a unified way. After getting the exception information, you can sit and handle it. For example, it provides a unified web interface to view the exception information, or it sends SMS or email t ...
Posted by Zaid on Fri, 20 Mar 2020 12:20:20 -0700