Some mistakes of Java basic knowledge

1, Use equals() correctly Object's equals method is easy to throw null pointer exceptions. You should call equals with a constant or an object with a value. String str = null; if (str.equals("abcd")) { ... } else { ... } If the variable str is null, a null pointer exception will be thrown. If there is no catch to catch and handle (we gene ...

Posted on Sat, 14 Mar 2020 00:11:09 -0700 by iffo

How are external configuration property values bound to XxxProperties class properties?--SpringBoot Source

Note: This source analysis corresponds to SpringBoot version 2.1.0.RELEASE 1 Preface This Join How does SpringBoot achieve automatic configuration?--SpringBoot Source (4) So let's review the previous one briefly. In the previous one, we analyzed the related source code of SpringBoot auto-configuration. Auto-configuration related source code ha ...

Posted on Fri, 13 Mar 2020 10:14:38 -0700 by chixsilog

opencv basic threshold to achieve image threshold output · basic explanation (including gif effect picture)

Article directory Explanation purpose display Threshold function: cv.threshold application image threshold operation Introduction to function parameters Basic introduction to threshold type Code instance Gray image example Traverse (grayscale) all cases - all threshold type effects display (and co ...

Posted on Fri, 13 Mar 2020 09:18:45 -0700 by silviuchingaru

SV experiment -- switch1

I. Introduction We will verify the Switch RTL core. Here are the steps to verify the Switch RTL core. 1) Understanding specification s 2) Develop validation plan 3) Establish the verification environment. We'll build the environment in multiple phases, so you can easily learn step-by-step. Phase 1) we ...

Posted on Fri, 13 Mar 2020 04:12:20 -0700 by cfemocha

adb command in self timer tutorial 43 read hardware configuration with one click

During Android system testing, For example, the iccid or uuid of the device is needed for interface testing, VIN number (vehicle unique identification number) is required for on-board test, The configuration word parameters of IMEI number and other equipment shall be designed for 4G test, We can also read the resolution of the device, emmc dis ...

Posted on Thu, 12 Mar 2020 22:45:10 -0700 by tempi

Spring IOC container source code analysis - get singleton bean

public Object getBean(String name) throws BeansException { // getBean is an empty shell method. All logic is encapsulated in the doGetBean method return doGetBean(name, null, null, false); } protected <T> T doGetBean( final String name, final Class<T> requiredType, final Obj ...

Posted on Thu, 12 Mar 2020 21:36:52 -0700 by loureiro

The study notes of calf -- sonar data analysis

This lecture: How to load and prepare data How to create a baseline neural network How to use scikit learn and k-fold cross validation to evaluate Keras model How data preparation can improve your model performance How to adjust the network topology can improve the performance test of the model 1. ...

Posted on Thu, 12 Mar 2020 21:27:09 -0700 by kovudalion

A simple example of C + + calling tinyxl2 to traverse all xml nodes and use map output

A simple example of C + + calling tinyxl2 to traverse all xml nodes and use map output This example only needs 3 files in total To get all the codes, please go to github download address: Bily Bily has a detailed video explanation address: main.cpp ElectronicProduct.xml Other This example only ...

Posted on Thu, 12 Mar 2020 20:54:21 -0700 by jabapyth

python foundation - object oriented 2 - encapsulation

Object oriented programming has three characteristics: encapsulation, inheritance and polymorphism python is also an object-oriented language To illustrate with an example: class user(object): def __init__(self, name, age,work): self.name = name self.age = age self.work = wo ...

Posted on Thu, 12 Mar 2020 03:20:01 -0700 by whitchman

MYSQL database index

Index overview In MySQL, an index is composed of one or more columns in a data table. The purpose of creating an index is to optimize the query speed of the database. Where, the index created by the user points to the specific data location in the database. When users query the data in the database by index, they do not need to traverse all t ...

Posted on Thu, 12 Mar 2020 02:08:04 -0700 by phpcodec