• Red hat 6 enterprise system troubleshooting


    rm /boot/* -rf dd if=/dev/zero of=/dev/sda bs=446 count=1 rm -f /etc/inittab rm -f /etc/rc.d/rc.sysinit rm -f /etc/rc.d/rc.loacl mv /etc/fstab /etc/fstab.bak The following four steps are summarized: 1. Restore fstab 2. Reinstall the kernel 3. Reinstall inittab, / etc / rc.d/rc.sysinit, / etc / rc.d/rc.loacl 4. Rewrite the boot file Specific: 1. Boot from the CD-ROM […]

  • Freefilesync – automatic folder synchronization


    In the relevant settings of the enterprise, if two physical machines need to achieve file synchronization between the master and slave, freefilesync can be recommended as the automatic synchronization setting Don’t talk too much, just take the opportunity   Start setting up file comparison – click red funnel setting (comparison / synchronization)     Click […]

  • IView form user defined verification, prompt information does not disappear


    IView form user-defined verification. After opening the bullet box, the red prompt message of the parent bullet box does not disappear,Because the parent bullet box does not receive the information of the bullet box; resolvent //Write the position above the data return const validate_dept = (rule, value, callback) => { value = this.addInfo.deptId || this.modifyInfo.deptId […]

  • java.lang.ClassCastException : com.sun.proxy .$Proxy16 cannot be cast to com.Charon.service . userserviceimpl solution


    Today, when learning dynamic proxy in spring AOP, we encountered a problem of type conversion java.lang.ClassCastException : com.sun.proxy .$Proxy16 cannot be cast to com.Charon.service .UserServiceImplFirst, introduce the dynamic proxy of spring.Spring uses two kinds of dynamic proxy: JDK proxy and cglib. Using the former, you must implement at least one interface to intercept methods. Using […]

  • Canvas center rotation, center scaling


    1、 Center rotationeffect: code: var canvas = document.createElement(‘canvas’); canvas.width = 500; canvas.height = 500; canvas.style.backgroundColor = ‘#ddd’; document.body.appendChild(canvas); var ctx = canvas.getContext(‘2d’); var x = 100, y = 100, width = 150, height = 150, angle = 90, Rectcenterpoint = {X: x + width / 2, Y: y + height / 2}; // center point […]

  • Using canvas to draw a circular (ARC) progress bar


    The results are as follows Can show the whole circle, semicircle and any angle arc (left and right symmetry) progress bar. The overall idea is as follows: First determine the shape of the display, the whole circle, semicircle or general arc Divide the arc of the determined shape into 100 equal parts and calculate the […]

  • Flex layout achieves left alignment of some elements and right alignment of some elements


    There are three inline right aligned buttons in a single flex container. The effect is as follows: If you want to keep the red button to the left and the other two blue buttons to the right At this time, we can add the following for the red button:margin-right: auto; The effect is as follows: […]

  • Red black tree


    R-B tree, also known as red black tree, is a special binary search tree. Each node of the red black tree has a storage bit to represent the color of the node, which can be red or black. The characteristics of red black tree are as follows Nodes are red or black. The root node […]

  • Red Hat Red Hat Linux 9 CD boot installation process diagram


    RedHat Linux is the most widely used linux operating system in the world. Because it has the best graphical interface, it is very convenient to install, configure or use, and runs stably. Therefore, both novice and old players have a high evaluation of it. Now, RedHat Linux has released a new version of 9.0, which […]

  • Layout detection and optimization of program performance optimization (2)


    Alibaba P7 mobile Internet architect advanced video (in daily update) for free learning, please click: https://space.bilibilibili.com/474380680This article will continue to introduce layout detection and optimization from the following two aspects: [HierarchyViewer] [Layout Inspector] 1、 Details of using hierarchy viewer 1.1. Function The hierarchy viewer tool provides a hierarchical structure of visual interface display layout, which […]

  • Is the code displayed inaccurately when querying version differences?


    Please see the screenshot~ The code of red border is deleted by me, and the code of blue border is changed according to SVN~This should be determined by SVN judgment. It seems strange to me, although the result is the same~

  • Linux bash printer run time


    #!/bin/bash function ShowTime() { endTime=`date +’%Y-%m-%d %H:%M:%S’` start_seconds=$(date –date=”$startTime” +%s); end_seconds=$(date –date=”$endTime” +%s); usedTime=$((end_seconds-start_seconds)) #Display in red font for more than 2 seconds, yellow font for 1-2s and green font for less than 1 s if [[ $usedTime -ge 2 ]] then echo -e “\033[31mUsed time:$usedTime s \033[0m” elif [[ $usedTime -ge 1 ]] then […]