Programmer Think

1, Foreword In our daily development, we cannot avoid parameter verification. Some people say that the front end will verify in the form? In the back-end, we can directly judge the filtering regardless of how the front-end judges it. Our back-end needs to judge again for security. Because the front end is easy to request. When the test use ...

Comparison operator= <=> <> != < <= > >= The comparison operator is used to compare the operands on the left and right of the expression. If the comparison result is true, it will return 1, if the comparison result is false, it will return 0, and in other cases, it will return NULL.Comparison operators are often us ...

spring is a framework, a container and an ecosystem!. spring is singleton by default and supports circular reference. When changing to multiple instances, it is not supported. scope=“prototype” 1.bean life cycle class - > instantiation - > Object - > attribute filling (dependency injection: @ Autowired attribute assign ...

Use of FactoryBean FactoryBean FactoryBean is an interface. The interface declaration is as follows: package org.springframework.beans.factory; import org.springframework.lang.Nullable; public interface FactoryBean<T> { String OBJECT_TYPE_ATTRIBUTE = "factoryBeanObjectType"; @Nullable T getObject() throws Exception; ...

1,IOC Inverse of Control – IOC, control reversal, reversing the control of the object to Spring! Using IOC can solve the problem of high coupling of programs Control reversal Suppose I need a function. In this function, I need to call the service layer, and then call the dao layer to get the data. Traditional Java EE development direc ...

day09 [thread status, wait and wake-up, Lambda expression, Stream flow] Today's content Multithreading Thread status -------- -- > must be masteredWaiting for wake-up mechanism -------- must be mastered Lambda expression Usage scenarios of Lambda expressions -------- -- > it is recommended to masterFormat of Lambda expression (sta ...

Basic introduction and advanced series of articles on Android development are being released and shared with you. Interested partners can follow bloggers! Explore and learn Android technology together to help you fight on the road of programming! catalogue 1, RadioButton radio box 2, CheckBox check box 3, Spinner drop-down box 4, ListVie ...

1, eureka use https://www.cnblogs.com/yxth/p/10845640.html Access address: http://127.0.0.1:8761/   2, Chaos monkey spring boot 1. What is the goal of chaos monkey Inspired by the principles of chaos engineering and the distributed system based on springboot, I want to test and know the best performance of the application, especially the ...

1, Origin 1. Generic from jdk1 5 is added to the Java language. Its main purpose is to solve the problem of ClassCastException. There will always be security risks during the downward transformation of objects. It can compile, run and solve most of the errors 2. The essence of generics is that the parameters and return values of attributes or ...

aggregate Java collection class is a kind of container, which can hold other data. It is used to store multiple objects with different quantities. It can also be used to store associative arrays (data pairs) with mapping relationships Overall, According to different storage data formats (single column or double column), it can be simply divid ...