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1. First answer why To ensure the immutability of String objects 2. How does final ensure the immutability of String objects? To answer this question, you must first know the function of final: The class decorated by final cannot be inheritedThe reference of final modification cannot be re assigned after initializationThe method of final mo ...

MyBatis multi table operation Multi table query means that when the query returns the result, it cannot automatically match the number. We will manually seal a Map for it and manually Map the data manually. The following two tables are used as examples orders table: users table: example: one to one query. One order corresponds to one use ...

What is expression language (EL)? Expression language (EL) is a mechanism that simplifies storage in Java  Accessibility of data in Bean components and other objects (such as requests, sessions, applications, etc.). There are many operators in JSP that are used in EL, such as arithmetic operators and logical operators to execute expressions. I ...

#Using Redis to optimize login module Redis is used to optimize the functions with high access frequency that will affect efficiency Use Redis to store verification code [the transfer of external chain pictures fails, and the source station may have anti-theft chain mechanism. It is recommended to save the pictures and upload them d ...

Four serialization mechanism 4.1 basic knowledge Thrift supports serialization and deserialization of binary, compressed format, and json format data. Developers can choose the specific form of the protocol more flexibly. The protocol is freely extensible. The new version of the protocol is fully compatible with the old version!Previously ...

1. Transaction usage example in JDBC mode 1) Create data table structure CREATE TABLE user ( id int(11) NOT NULL auto increment, name varchar (255) default NULL , age int ( 11 ) default NULL , sex varchar (255 ) default NULL , PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; 2) Create corresponding PO public class User ...

Java Vue+SpringCloud integration before and after the completion of Alipay payment (sandbox) operation process [detailed] The realization of Alipay payment function in our project is actually very simple. Don't say much, come straight to the point! preparation Baidu enters Alipay official website Choose me to be a developer Click ...

#Follow and cancel [the transfer of external chain pictures fails, and the source station may have anti-theft chain mechanism. It is recommended to save the pictures and upload them directly (img-xwZ8AhZC-1646567007779)(D:\TyporaNotes \ Niuke forum project \ Chapter III pictures \ image-20220306104936732.png)] Design the key and Valu ...

Hello, I'm Xiaofu~ Technology exchange pays attention to official account: something inside programmers Portal: Original address Git should be familiar to everyone. Skillfully using git has become a basic skill of programmers. Although there are cow X client tools such as Sourcetree at work, which makes it convenient to merge code. But job i ...

SpringBoot-20-Mybatis code generation What is Mybatis? Mybatis is an open source project of apache ibatis, which was officially renamed mybatis in 2010. It is a Java persistence layer framework. The persistence layer framework provided by ibatis includes SqL Maps and Data Access Objects(Daos) Mybatis features: Mybatis is easy to learn: you ...