以前一直使用的是Eclipse，听别人介绍说IDEA非常不错，也为了以后转Android studio铺垫下。就开始尝试用idea来开发。 这篇文章主要学习了idea的使用技巧。 IDEA 全称 IntelliJ IDEA，是java语言开发的集成环境，IntelliJ在业界被公认为最好的java开发工具之一，尤其在智能代码助手、代码自动提示、重构、 J2EE支持、Ant、JUnit、CVS整合、代码审查、 创新的GUI设计等方面的功能可以说是超常的。IDEA是JetBrains公司的产品...
在Java应用程序运行时，Java虚拟机会保存一份内部的运行时常量池，它区别于class文件的常量池，是class文件常量池映射到虚拟机中的数据结构。 1.CONSTANT_Class入口解析 数组类的符号解析较为特殊。若是基本类型数组，那么虚拟机将创建该基本类型的新数组类，并创建一个Class实例来代表该类型，数组类的定义类加载器为 启动类加载器。若是引用类型的数组，那么在此之前还会进行引用类型的解析，数组类的定义类加载器为引用类型的定...
总结:mybatis传单个类型参数（String、Integer）,在dao层方法中可以不用@param注解,前提是xml中不含有条件表达式(when,if..标签中没有引用到该参数)1、错误信息： 2、mapper.xml、dao方法： 3、如果把mybatis的<if>标签去掉，就可以正常运行并接收传递的参数。如果想要使用条件表达式，那就要在dao层方法中加@Param("leader") 4、加标签后运行正常！ ' in 'class java.lang.Integer'' ref='nofollow'>org.apache.ibatis.ref...
Part 1http://techmytalk.com/2014/01/24/java-interview-reference-guide-part-1/Posted on January 24, 2014 by Nitin KumarJAVA Object Oriented ConceptsJava in based on Object Oriented concepts, which permits higher level of abstraction to solve any problem in realistic way.Object oriented approach conceptualize the problem solution in real-world object which are easier to reuse across the applicatio...
可视化编辑器,alt+1到9键,切换到工具区,tab键,选择按钮,esc键,返回编辑 public class TestIO { public static void main(String[] args) { String filename = "D:" + File.separator + "hello.txt"; File file = new File(filename); System.out.println("标准输出 -- 控制台"); try { //FileOutputStream fileOut = new FileOutputStream(filename); PrintStream prt = new PrintStream(file); System.setOut(pr...
Java自定义实现String转换为int 的简单实现！publicclass StringToInt {publicstaticint stringToInt (String str){char[] num = str.toCharArray();//得到各个字符的charint result = 0;for(int i = 0; i < num.length; i++){if(num[i]>57||num[i]<48){//0~9对应的Ascall码System.out.println("数据格式错误，转换失败！！！");thrownew NumberFormatException();}else{result+=(num[i]-48)*(Math.pow(10, num.length-i-1));}}ret...
相等有两种，其一是==表示的引用等价，另一种是每个对象继承自Object或自己重写的equals方法所表示的对象等价通常来说两个Integer对象即使值相同，在用==判断引用等价的时候也会不相等，因为他们所处的内存地址不相同。然而在对Integer对象使用==比较的时候存在着一个特殊情况，当两个对象的值都在-128至127之间的时候，他们的数值相等的同时也会有引用等价，也就是说他们来自同一个内存地址。这是因为jvm在运行时创建了一个缓存区...
Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999. 将阿拉伯数字转换为罗马字符 建立一个二维数组来代表转换表 代码如下：public class Solution {public String intToRoman(int num) {String[][] sss={{"I","II","III","IV","V","VI","VII","VIII","IX"},{"X","XX","XXX","XL","L","LX","LXX","LXXX","XC"},{"C","CC","CCC","CD","D","DC","DCC","DCCC","CM"},{"M","...
API是Java提供的基本编程接口 可以看Oracle提供的相应的API文档，用于开发者如何使用这些类，以及这些类包含的方法。 原文：https://www.cnblogs.com/xudong97/p/11147826.html
Clone Graph:Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.OJ‘s undirected graph serialization:Nodes are labeled uniquely. We use # as a separator for each node, and , as a separator for node label and each neighbor of the node. As an example, consider the serialized graph {0,1,2#1,2#2,2}.The graph has a total of three nodes, and therefore contains ...
<!DOCTYPE html><html> <head> <meta charset="UTF-8"> <title></title> <style> .lala{ text-align: center; } </style> </head> <body> <div class="lala"> <input type="button" value="当前时间" onclick="anniu()"/ style="width: 80px;height: 20px;" > <input type="text" id="xi"/> <script> setInterval(function anniu(){ var oDate = new Date(); var oyear=oDate.getFullYear(); ...
目录1 问题描述2 解决方案 1 问题描述Problem Description We call a number interesting, if and only if: 1. Its digits consists of only 0, 1, 2 and 3, and all these digits occurred at least once. 2. Inside this number, all 0s occur before any 1s, and all 2s occur before any 3s. Therefore, the smallest interesting number according to our definition is 2013. There are two more interseting nu...
PHP print_r的函数很好用，网上娱乐城可以用来打印数组、对象等的结构与数据，可惜JavaScript并没有原生提供类似的函数。不过我们可以试着自己来实现这个函数，下面提供一些方法与思路。方法一function print_r(theObj) {var retStr = ‘‘;if (typeof theObj == ‘object‘) {retStr += ‘<div style="font-family:Tahoma; font-size:7pt;">‘;for (var p in theObj) {if (typeof theObj[p] == ‘object‘) {retStr += ‘<div><b>...
package com.day9.Wrapclass;public class Demo { public static void main(String[] args) { Integer i1 = new Integer(97); Integer i2 = new Integer(97); System.out.println(i1 == i2);//false两个对象，不同的地址值 System.out.println(i1.equals(i2));//true System.out.println("-----------"); Integer i3 = new Integer(197); Integer i4 = new Integer(197); System.out....
<script type="text/javascript"> var i=1; var IR1 = setInterval("myMethod()",1000); function myMethod(){ i++; console.debug(i); console.debug("a"); if(i>20){ clearInterval(IR1); } }</script> 程序思路：1、创建中断对象var IR = setInterval(myMethod(),1000);1000表示1s间隔，每个单位1ms 2、创建回调函数int i = 1;function myMethod() { i++;} 3、为了让每次1s输出调用...