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title: javaEE(SSM) learning notes 4: dynamic SQL Dynamic SQL import [main function]: splice SQL clauses according to different conditions or different data to achieve similar programming effect in XML files. [main element (mark)]: Query criteria: single branch if; Multi branch choose... when... other Special treatment: where /trim Up ...

1, What exactly is the $symbol? $is the attribute defined for the window object in jQuery $and jQuery can be interchanged when used. In fact, it is a function, which comes from the jQuery library jQuery and $are used as an attribute of window             window.jQuery = window.$ = jQuery;             ...

From: https://www.eet-china.com/mp/a55310.html hello, everybody. Today I'm going to take you to learn about USB device driver. Kernel version: 4.4.94 1. Linux USB subsystem Before introducing device-side drivers, let's look at the Linux USB subsystem. The subsystem here is relative to the entire Linux kernel, not a single device. The communic ...

linux bg and fg commands Under linux, if we want a task or program to be executed in the background, we can use &. In fact, linux also provides commands for other task scheduling. bg: change a command suspended in the background to continue execution; [background background background]fg: transfer the command in the background to the fore ...

Environment Configuration Linux 0 .vimrc #Create a new file in your own directory (~). vimrc vim ~/.vimrc #Add a text configuration (as follows... #Indicates how many spaces a tab shows by default 8 set tabstop=2 #Represents the length of the indentation that falls back when the backspace key is pressed in edit mode set softtabstop=2 #Re ...

Using invariance to solve concurrency problem Invariance pattern We know that concurrency is the most likely cause of thread insecurity. The main reason is that there is data competition. If multiple threads read only and do not modify the same variable, there will be no thread safety problem. This idea is actually very simple, but it is also ...