Java executable command jstat 1 Concept 2 Advantages and Disadvantages 3 Use 3.1 Grammar format 3.2 Usage tips 3.3 Optional parameters: -class 3.4 Optional parameter: -compiler 3.5 Optional parameters: -gc 3.6 Optional parameters: -gcutil 4 Application scenarios Summarize 1 Concept jstat is a performance monitoring tool provided by the Java virtual machine for real-time monitoring […]
Tag: jst
JSP+JSTL+EL expression, realize the page jump function of web pages (previous page, next page, first page, last page page jump)
1. Paging display is everywhere significance: In practice, all data will not be displayed together, so the paging display of data needs to be considered 2. Preliminary preparation (1) jar package (2) Import the c tag library <%@ taglib prefix=”c” uri=”http://java.sun.com/jsp/jstl/core” %> 3. Concrete Realization Analysis Realization: first page previous page Through hyperlinks, jump to […]
[Java executable commands] (21) Thread snapshot generation tool jstack: Help developers analyze and troubleshoot thread-related problems (deadlock, infinite loop, thread blocking…)
jstack of Java executable commands 1 concept 2 Advantages and disadvantages 3 use 3.1 Syntax format 3.2 Use steps and skills 3.3 Use cases 4 Application scenarios Summarize 1 concept The jstack command is a diagnostic tool provided in the Java Development Kit (JDK) to generate thread snapshots of the Java Virtual Machine (JVM). Its […]
jsts + openLayer solve geometric self-intersection error problem
Error: TopologyException: found non-noded intersection between LINESTRING ( 13022630.89845247 5279155.061076987, 13022019.402226187 5278543.81202375 ) and LINESTRING ( 13022 546.663871666 5273866.515213738, 13022019.402226187 5286795.6742424425 ) [ (13022342.73927607, 5278867.01837748, NaN) ] Solution Create a closed line based on coordinate data by instantiating jsts.gemo.GeometryFactory, and use the isSimple method to determine whether it is self-intersecting. If it is self-intersecting, create […]
Linux troubleshooting java cpu too high problem, JPS, JMAP, JSTAT, JSTACK and JCMD
code: [root@localhost cpu]# cat Test.java public class Test { public static void main(String[] args) { new Thread(()->{ System.out.println(“11111″); while(true) { } },”thread1”).start(); new Thread(()->{ System.out.println(“2222″); try { Thread. sleep(100000L); } catch (InterruptedException e) { throw new RuntimeException(e); } },”thread2”).start(); new Thread(()->{ System.out.println(“33333”); try { Thread. sleep(100000L); } catch (InterruptedException e) { throw new RuntimeException(e); } […]
[JSP] Use JSTL to enhance JSP functions
This article is for learning reference only! JSTL stands for JavaServer Pages Standard Tag Library; it provides a core set of web page functionality that can perform many basic tasks such as conditional and iteration of structural elements, manipulation of XML documents, and support for internationalization tags to more complex SQL element processing. JSP is […]
BCSP-Xuanzi Java Development Java Web Programming CH08_Using EL and JSTL to Simplify JSP Pages
BCSP-Xuanzi Java Development Java Web Programming CH08_Using EL and JSTL to Simplify JSP Pages EL expressions Disadvantages of Writing Java Script in JSP Program structure is complex poor readability difficult to maintain <td width=”380″>@<%= blog.getOrigin().getUser().getNickname() + “:” + blog.getOrigin().getContent() %></td> Using EL expressions can greatly simplify JSP code <td width=”380″>@${blog.origin.user.nickname} : ${blog.origin.content}</td> Get to know […]
Dynamic Web Development 07: EL and JSTL
EL and JSTL I. Introduction 2. Notes (1), EL basic grammar 1. The concept of EL 2. The grammar of EL 3. Features of EL Basic Grammar (2) Identifiers in EL 1. Specification of identifiers in EL 2. Examples of identifiers in EL (1) Legal identifier (2) Illegal identifier (3) Keywords in EL (4) Variables […]
Analysis of EL expressions and JSTL in simple terms
el-expression Generating background Starting from JSP2.0, it is not recommended to use java scripts, but to use el expressions or dynamic tags instead of java scripts; page tags; Concepts and principles Concept: Expression Language: an expression language built into jsp; Principle: The purpose of the el expression is to replace the in the script of […]
Use the jstack command to analyze the problem of high CPU usage
Environment Ubuntu 22.04 JDK 17.0.3.1 Introduction The jstack command prints Java stack traces of Java threads for a specified Java process Usage: jstack [-l][-e] options: -l : long listing. Prints additional information about locks -e : extended listing. Prints additional information about threads Test Java code below: package pkg1; public class Test0608 {<!– –> public […]