java编程IO操作必不可少的,很久不玩IO,回顾一下,写了几个小程序,记录一下,方便查阅和学习. 1.给出一个整数数组,将其写入一个文件,再从文件中读出,并按整数大小逆序打印. package com.io.test; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileReader; import java.io.FileWriter; i…

Immutable Strings Objects of the String class are immutable. If you examine the JDK documentation for the String class, you’ll see that every method in the class that appears to modify a String actually creates and returns a brand new String object c…

1.java的数据类型分为两种:简单类型和引用类型(数组.类以及接口).注意,java没有指针的说法,只有引用.简单类型的变量被声明时,存储空间也同时被分配:而引用类型声明变量(对象)时,仅仅为其分配了一个引用类型的内存,类似于c++里面的指针类型.要使用new来为此对象分配实际需要的内存,即实例化. Eg: (1):数组:int a[][];a=new int[1][2];一般常常把int a[][]写为int[][] a. 需要注意的是:数组还可以直接用数据列表来初始化,省去new操作:in…

IO流机制 File类的使用 File类的构造方法 File(URI uri) File(String pathname) File(File parent, String child) File(String parent, String child) File类的常用方法 boolean exists():判断文件是否存在 boolean createNewFile() :创建一个新文件,只能创建一个文件,不能创建目录(文件夹),创建时先判断文件 是否存在 ,不存在则创建并返回true, 存…

The ideal time to catch an error is at compile time, before you even try to run the program. However, not all errors can be detected at compile time. To create a robust system, each component must be robust. By providing a consistent error-reporting…

At the lowest level, data in Java is manipulated using operators Using Java Operators An operator takes one or more argument and produces a new value. The arguements are in a different form than ordinary method calls, but the effect is the same. + :…

---恢复内容开始--- Both C++ and Java are hybird languages. A hybird language allow multiple programming styles The reason C++ is hybird is to support backward compatibility with the C langguage (a superset of the C language) The Java language assumes that…

The genesis of the computer revolution was a machine. The genesis of out programming languages thus tends to look like that machine. 计算机革命起源于机器,因此编程语言的产生也始于对机器的模仿 Computers are mind amplification tools and a different kind of expressive medium. 计算机是大…

Learn Java I found out that I and other speakers tended to give the typical audience too many topics too quickly. 我发现我和其他的演讲者往往会在极短的时间内传递太多的主题给听众. I wanted to try to keep everyone up to speed. 我想尽力让每个人都跟上进度 Thinking in Java seminars “Thinking in Java…

首先要先理解什么是 stream ? stream代表的是任何有能力产出数据的数据源,或是任何有能力接收数据的接收源. 一.不同导向的 stream 1)以字节为单位从 stream 中读取或往 stream 中写入信息 InputStream: a)ByteArrayInputStream:把内存中的一个缓冲区作为InputStream使用 b)FileInputStream:把一个文件作为InputStream,实现对文件的读取操作 c)PipedInputStream:实现了pipe的概念…