Java
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Java tool class for connecting to MySQL database
A encapsulated tool class that links to the MySQL database can easily obtain the connection object and close the state…… -
Introduction to command mode of Java design pattern
Command mode is the one that puzzles me most. After reading a lot of code, I feel that I vaguely master its general pr…… -
Introduction to decorator pattern of Java design pattern
Decorator is often translated into "decoration". I think it is more vivid to translate it into "painter". Painter is u…… -
Java – query object pattern
I need to implement a query object pattern in Java for my customizable search interface (webapp being written) Does an…… -
Set the default application icon image in Java swing on OS X
I'm setting up an icon image for a jar file: setIconImage(new ImageIcon(getClass().getResource("logo.png")).getImage()…… -
The windows process executed by the java process did not terminate
I create a process on windows from Java My problem is that this process will not end This is an example program: impor…… -
Java – is it bad practice to capture numberformatexception?
I have to parse a string that can take hexadecimal or other non hexadecimal values 0xff, 0x31 or a, PC, label, etc I u…… -
Java – JDBC transaction and connection clarification
I'm using JDBC to talk to my Postgres database If my entire application runs a single connection, that is, there is on…… -
@ preauthorize at the type level of Java – spring security cannot be overridden at the method level
I try to protect the controller with a type level @ preauthorize annotation and try to override this behavior by using…… -
Java print string variable
When I run (seemingly simple) code, I get some strange output This is what I have: import java.util.Scanner; public c…… -
Java – Tomcat spring and environment variables
In the spring file, I have: <bean id="propertyConfigurer" class="org.myapp.MyConfigurator"> <property…… -
Java – how to make the variable method take a single array as the first value of the varargs array?
Given the variable: Object[] ab = new Object[] { "a","b" }; Object[] cd = new Object[] { "c","d" }; When the following…… -
Java – resulset – cursor: rs.next() takes a lot of time
The cursor I returned from the database executes in 31 MS (milliseconds) But when I use this cursor to get more than 1…… -
Java – the jdbc driver throws a “resultset closed” exception on an empty resultset
I have a problem with the jdbc driver for SQLite I am using the select statement to execute the query If I get an empt…… -
Java – compare log4j and logger
Compare the logger of JDK with Apache log4j? Which is more suitable for a new project for Java 6? How do they compare …… -
Java – different series of xyline charts in different colors JfreeChart
I have created an XY line graph using JfreeChart. There are two data sets. I want both rows to be in different colors …… -
Java 7 switch statement, string does not work
According to the Java tutorials, in Java se 7 and later, you can use string objects in expressions of switch statement…… -
Reduce image resolution in Java
I need to use a java program to reduce the size of the image (not the width and height) I need to reduce the size from…… -
Why can’t violation parameter types in Java be overridden?
Java allows return types to be covariant when overriding superclass methods Why is it not allowed to use opposite para…… -
Java – use static variables in spring annotations
I am using spring's preauthorize annotation as follows: @PreAuthorize("hasRole('role')"); However, I have defined 'rol…… -
Java – a good tool for debugging verifyerror
I found bytecode verifyerrors notoriously difficult to debug JVMs provide little feedback, usually just the current cl…… -
Java – synchronization difference between field reading and volatile
In a good article with some concurrency tips, an example is optimized to the following lines: double getBalance() { …… -
Java – find the complement of color programmatically?
Is there any way to find the complement of the color of a given RGB value? Or can only find some colors? Will anyone d…… -
Java – implementation comparable to generic classes
I want to define a class that implements a general comparable interface In my class, I also define a generic type elem…… -
Java: freeze objects accessible from the final field
Dzone refcard entitled "core Java concurrency" points out: and I am not fully aware of the second statement Does this …… -
Java – what is the point of beans?
I have some JSP tutorials for beans. I don't understand what a bean class is All is to get and set methods Why use the…… -
Java – log4j what is the difference between rollingfileappender and dailyrollingfileappender?
What is the difference between log4j rollingfileappender and daily rollingfileappender? Solution read http://www.mail-…… -
Multithreading – deep analysis of the differences between CPUs and GPUs
I've been looking for the main difference between CPU and GPU, more accurately, separating the subtle differences betw…… -
Java – can you share a link to a URL parsing implementation?
As far as I know, the URL consists of the following fields: >Protocol (HTTP, HTTPS, FTP, etc.) > user name > …… -
How to calculate the average value of multiple numbers sequentially using java 8 lambda
If I have a collection point, how can I use the Java 8 stream to calculate the average of X and Y in a single iteratio…… -
How do I debug a Java Web start application?
I have a Java Web start application that starts from a real-time site by downloading custom JNLP files The problem is ……