Programmer Think

The company is investigating the internal data account leakage these days. The reason is that it is found that some interns xiaocute secretly transmitted the source code to GitHub with their account and password, resulting in the leakage of core data. The children still haven't been severely beaten by the society. The consequences of this can b ...

Differences between HashMap and ConcurrentHashMap ConcurrentHashMap divides the whole bucket array into segments, and then protects each segment with a lock lock. Compared with the synchronized lock of HashTable, the granularity of the lock is finer and the concurrency performance is better. However, HashMap has no lock mechanism and is not t ...

I often see some articles on design patterns, write a lot of content, and give some "vivid" examples. But it may have the same problem as the Head First design pattern: after reading it, I will, but it doesn't seem to be useful? Or hard cover design pattern. ​ Take a few extreme examples I've seen: Two fields, and a Builder3 if ...

"a""b" 127.0.0.1:6379> lset list1 0 v OK 127.0.0.1:6379> lrange list1 0 -1"v""b" - lrm : Delete an element and return the number of deleted elements ```java 127.0.0.1:6379> lrange list1 0 -1 1) "b" 2) "b" 3) "a" 4) "b" 127.0.0.1:6379> lrange list1 0 -1 1) "a" 2) "b" lindex: returns the element at the specified position in ...

<!--Spring Boot--> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.6.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <!--eureka--> <dependency&g ...

Usage scenario: when the amount of data fetched reaches a certain level, paging is required for data segmentation. When we do not use the paging function, we will face many problems: Problems with the client: if too much data is displayed on the same page, the user experience will be seriously affected because the page is too long, it is ...

Core concepts The important components are described below: Broker: The Message Queuing service process, which consists of two parts: Exchange and Queue. (Post Office / Express) Exchange: A message queue switch that routes messages to a queue according to certain rules and cares about messages. (courier in post office/courier in express compa ...

<property name="password">123456</property> <property name="schemas">ITCAST</property> 123456 ITCAST true ``` After configuration, restart MyCat service; Description of attribute meaning: checkSQLschema When the value is set to true Time, If we execute the statement"select * from test01.user ;" Statement time, MyC ...

fis.close(); } /* * Method to realize file replication * 1. Byte stream reads and writes a single byte */ public static void copy_1(File src,File desc)throws IOException{ FileInputStream fis = new FileInputStream(src); FileOutputStream fos = new FileOutputStream(desc); int len = 0 ; while((len = fis.read())!=-1){ ...

Hello everyone, today is cloudy. There are 3816 lightning flashes in Hangzhou. Take a closer look, it originally consists of four big characters: design mode! Today is another day of design mode. What Hong Jue wants to talk about today is strategy mode. Policy pattern is a kind of behavioral pattern. This kind of design pattern pays special a ...