Programmer Group

  introduction It is said that StringBuilder is more efficient than String in handling String splicing, but sometimes there may be some deviation in our understanding. Recently, when I tested the efficiency of data import, I found that my previous understanding of StringBuilder was wrong. Later, I found out the logic of this piece by mea ...

mybatis supports different databases. The specific access to the database is the driver jar package provided by different database manufacturers. For example: mysql-connector-java.jar of MySQL The jar s provided by different manufacturers are also implemented based on the interface in the java.sql package under the JDK For example, different d ...

2019 1. Students' scores can correspond to different grades according to different score segments, for example, 90-100 is A; 80-89 points are B; 70-79 is divided into C; 60-69 points are D; Below 60 points is E. It is required to input the student score of the hundred mark system, and output the score grade corresponding to the student score. ...

  0x01: byte stream Byte stream base class 1. InputStream InputStream: the base class of byte input stream. The abstract class is a superclass representing all classes of byte input stream. Common methods: // Reads the next byte of data from the input stream abstract int read() // A certain number of bytes are read from the input st ...

Content index Class loader Class loading system Class loading Dynamic class loading Dynamic class overloading Custom class overload Class load / reload example Java allows you to dynamically load and reload classes at run time, but this function is not as simple and direct as people want. This article will explain how to load and overload cl ...

Introduction ​​ Have nothing to do: The excrement shoveling officer made a hamster toy for the cat owner with waste cardboard boxes. Look, the owner has a lot of fun I knocked it out - eh, why, why are there two? Isn't it exciting? This is a good chance to improve your relationship with the master! ​​ Ha ha ha! After reading the above ...

prefaceIn daily development, we often use some date related data operations, such as obtaining the week corresponding to the date, obtaining the existence of a month, etc.The date API design before Java 8 is very anti-human. For the time created with new Date(), the year is obtained by 1 starting from 1900, and the obtained month 0 represents J ...

Compare, find, replace, split and intercept Java strings 1, String comparison 1. equals(): case sensitive, and the return value type is boolean; //Case sensitive comparison String str1 = "hello" ; String str2 = "Hello" ; System.out.println(str1.equals(str2)); // Return false 2. Case insensitive: equalsIgnoreCase(), the return value type ...

SpringBootAdmin is a monitoring tool for UI beautifying and encapsulating the actor interface of Spring Boot. It can browse the basic information, detailed Health information, memory information, JVM information, garbage collection information, various configuration information (such as data source, cache list and hit rate) of all monitored Spr ...

Spring Boot starter We know that Spring Boot greatly simplifies the initial construction and development process of the project, which are completed through the starter provided by Spring Boot. Pinda general permission system is developed based on Spring Boot, and some basic modules are starters in essence, so we need to have a comprehensive a ...