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Classification of 23 design patterns 1, Overview Definition of Flyweight pattern: using sharing technology to support reuse of a large number of fine-grained objects. It can reduce the number of objects to be created and avoid the cost of a large number of similar classes by sharing the existing o ...

brief introduction django provides a very useful component which is responsible for the full set of functions of user login authentication, which is the auth component. With the auth component, we no longer need to manually write the login check decorator, nor set session s manually to save user state. The django project executes the databas ...

Article catalog 1, CSS introduction 2, Grammatical format 3, How to use CSS 1. Embedded 2. Outer chain 3. Line style 4. Three style priorities and application scenarios 4, Selector 1. Basic selector 1. All tuple selection 2. Label selector 3. id selector 4. Class selector 5. Overall operation cod ...

The date type defined by the background database is Long, which is stored as a time stamp; the date type of the search box on the page is String.The String and Long types of dates are not equal on time stamps! I show you how to convert date types in my code, and you can understand the difference between debug and timestamp converters.     1. Fi ...

catalog 1, Sqoop export 2, Sqoop import 1, Sqoop export 1. Create a job to export the HDFS file to the MySQL database. (1) Open PDI and create a new job, as shown in Figure 1. Figure 1   (2) Edit the 'Sqoop export' job item, as shown in Figure 2. Figure 2 Description: CDH631 is a buil ...

catalog 1, Problem description 2, Step by step analysis of problems 1, java.net.SocketException : how is the broken pipe exception generated? What's the impact? 2. Why is the database TCP connection broken? 3. The effect of firewall cutting off database connection 3, Solutions 1. Adjust the cut-of ...

1, Background ES is a distributed search framework. It can quickly query data, mainly including elastic search, kibana (a web interface used to query es data) Where does the data come from? Of course, it comes from the database or inserts into ES one by one. So this time, the requirement is to impo ...

Authentication + Authorization Code Implementation Spring Security is a security framework based on Spring AOP and Servlet filters.It provides a comprehensive security solution while handling authentication and authorization at the Web request and method call levels. Previously, I blogged about the theory of authentication and authorization ...

1. Why divide tables?The database data becomes larger and larger, with too much data in a single table.This results in slower queries and database performance bottlenecks due to the lock mechanism of tables, which can seriously affect application operations.One mechanism in mysql is table and row locking to ensure data integrity.A table lock m ...

I was asked hundreds of times about IoC and AOP in my last interview, and I was still silly and confused?We understand the two ideas of IOC and AOP. Next, let's not consider how Spring achieves these two ideas. First, through a case of bank transfer, we analyze the code level problems in this case.Use our existing knowledge to solve these prob ...