Java基础_讲义

第一讲 Java语言入门1.1 Java的特点1.1.1面向对象：∙与C++相比，JAVA是纯的面向对象的语言C++为了向下兼容C，保留了很多C里面的特性，而C，众所周知是面向过程的语言，这就使C++成为一个"混血儿"。

而JAVA语法中取消了C＋＋里为兼容C所保留的特性，如取消了头文件、指针算法、结构、单元等。

1.1.2可移植（平台无关性）：∙生成中间字节码指令与其他编程语言不同，Java并不生成可执行文件（.exe文件），而是生成一种中间字节码文件（.class文件）。

任何操作系统，只要装有Java 虚拟机（JVM），就可以解释并执行这个中间字节码文件。

这正是Java实现可移植的机制。

∙原始数据类型存储方法固定，避开移植时的问题Java的原始数据类型的大小是固定的。

比如，在任何机器上，整型都是32位，而C++里整型是依赖于目标机器的，对16位处理器（比如8086），整数用两个字节表示；在像Sun SPARC这样的32位处理器中，整数用4个字节表示。

在Intel Pentium处理器上，整数类型由具体的操作系统决定：对于DOS和Win32来说，整数是2个字节；对于Windows 9x 、NT和2000，整数是4个字节。

当然，使整数类型平台无关之后，性能必然有所下降，但就Java来说，这个代价是值得的。

Java的字符串，则采用标准的Unicode格式保存。

可以说，没有这个特性，Java的可移植性也不可能实现。

1.1.3简单∙JAVA在语法上与C++类似JAVA的语法与C++很接近，有过C或者C＋＋编程经验的程序员很容易就可以学会JAVA语法；∙取消了C++的一些复杂而低效的特性比如：用接口技术代替了C++的多重继承。

C＋＋中，一个类允许有多个超类，这个特性叫做"多重继承"，多重继承使得编译器非常复杂且效率不高；JAVA的类只允许有一个超类，而用接口（Interface）技术实现与C＋＋的多继承相类似的功能其它被取消的特性包括：虚拟基础类、运算符过载等∙JAVA的基本解释器和类支持模块大概仅40K即使加入基本的标准库和支持线程的模块，也才220K左右。

JAVA基础课程讲义-图文北京尚学堂科技JAVA基础课程北京尚学堂科技JAVA基础课程目录第一章JAVA入门............................................................. . (10)计算机语言发展史............................................................. . (10)JAVA开发环境搭建............................................................. ...........................................18一个典型的JAVA程序的编写和运行过程............................................................. ......19第一个程序常见错误............................................................. ........................................20第一个JAVA程序的总结和提升............................................................. ......................20常用Java开发工具............................................................. ...................................................20常用do命令............................................................. (21)本章笔试作业............................................................. (21)本章上机操作............................................................. (21)第二章(1)编程的基本概念............................................................. (22)注释............................................................. ............................................................... .............22标识符............................................................. ............................................................... .........22关键字/保留字............................................................. ..........................................................23变量(variable)..................................................... ............................................................... .....24常量(Contant)...................................................... ............................................................... ...25命名规则(规范)............................................................ ..........................................................25基本数据类型(primitivedatatype)............................................ . (26)整型变量............................................................. (26)浮点型............................................................. ................................................................27字符型（2个字节）：......................................................... .........................................28boolean类型............................................................. .....................................................29运算符(operator)..................................................... (29)二元运算符.............................................................. .......................................................29一元运算符.............................................................. .......................................................30布尔逻辑表达符.............................................................. .. (30)2北京尚学堂科技JAVA基础课程位运算符............................................................. (30)扩展运算符............................................................. ........................................................31字符串连接符............................................................. ....................................................31三目条件运算符............................................................. ................................................31运算符优先级的问题............................................................. ........................................31自动类型转换............................................................. ....................................................32基本类型转化时常见错误和问题............................................................. ....................33方法............................................................. ............................................................... .............33简单的键盘输入和输出............................................................. ............................................33本章思考作业............................................................. (34)上机操作............................................................. ............................................................... .....34第二章(2)控制语句............................................................. (35)顺序结构............................................................. ............................................................... .....35选择结构............................................................. ............................................................... .. (35)if单选择结构............................................................. .....................................................35if-ele双选择结构............................................................. .............................................35If-eleif-ele多选择结构............................................................. ...................................36witch多选择结构............................................................. ............................................37循环结构............................................................. ............................................................... .. (39)While和dowhile的区别............................................................. ..................................41For循环............................................................. . (42)break语句和continue语句............................................................. .............................47语句块............................................................. ............................................................... .........48递归结构............................................................. ............................................................... .....49本章作业............................................................. ............................................................... .....50本章上机操作............................................................. (51)第三章JAVA面向对象程序开发............................................................. . (52)编程语言发展史............................................................. ........................................................52类和对象是如何产生发展的如何进化的............................................................. ............52面向对象思想初步(OOP初步ObjectOrientedProgramming)..................................... ........53面向对象编程的语言的三大特征简介............................................................. ....................56对象和类的概念............................................................. ........................................................56类和对象初步............................................................. (57)测试类的定义方式............................................................. ............................................57简单的学生类编写示例............................................................. ....................................58内存分析............................................................. (59)属性（field，或者叫成员变量）........................................................... .......................59引用类型............................................................. (60)类的方 (60)对象的创建和使用............................................................. ............................................60构造器(或者叫做构造方法,contructor)................................................. ......................60垃圾回收机制(GarbageCollection)............................................ ........................................63方法的重载(overload)，构造方法的重载............................................................. ...............63thi关键字............................................................. ............................................................... ..653北京尚学堂科技JAVA基础课程tatic关键字.............................................................. (66)静态初始化块（经常用来初始化类，加载类信息时执行！）...........................................67package...... ................................................................ .............................................................68J DK中的主要包.............................................................. ........................................................68import................................................................ .....68eclipe的使用.............................................................. ..........................................................69继承(e某tend,inheritance)............................................... .. (70)为什么需要继承？继承的作用？........................................................... ......................70继承介绍............................................................. (70)如何实现继承？........................................................... ..................................................70继承使用要点............................................................. ....................................................71Object 类............................................................. ............................................................... .. (72)toString方法............................................................. ......................................................72equal方法............................................................. ........................................................73uper 关键字............................................................. . (74)方法的重写（override）................................................... ....................................................74隐藏/封装(encapulation)................................................. .. (75)为什么需要封装？封装的作用和含义？........................................................... ..........75使用访问控制符，实现封装............................................................. ............................76封装的使用细节............................................................. ................................................76多态(polymorphim).................................................. . (76)为什么需要多态............................................................. ..............................................76如何实现多态............................................................. ..................................................77方法绑定(methodbinding)................................................ .........................................77静态绑定............................................................. (77)动态绑定............................................................. (77)多态的使用要点............................................................. ................................................78对象的转型(cating)....................................................... ........................................................79final ............................................................... ..........................................................................81抽象类............................................................. ............................................................... .........82抽象类的使用要点............................................................. ....................................................83接口............................................................. ............................................................... . (83)为什么需要接口............................................................. ..............................................84如何定义接口............................................................. ..................................................84接口的本质探讨............................................................. ................................................84接口使用要点............................................................. ....................................................85接口的多继承............................................................. ....................................................86面向接口编程............................................................. ....................................................87OOP更多应用............................................................. .. (87)组合............................................................. ............................................................... .....87内部类(innerclae).......................................................................................................88字符串（ng.String类）的使用............................................................. ..............90字符串相等的判断............................................................. ............................................92思考作业............................................................. ............................................................... .. (93)4北京尚学堂科技JAVA基础课程上机作业............................................................. ............................................................... .....94第四章异常机制............................................................. ............................................................... .95导引问题............................................................. ............................................................... .....95异常（E某ception）的概念............................................................. ........................................96异常分类............................................................. ............................................................... .. (96)Error.......................................................... ............................................................... .......97Error和E某ception的区 (97)E某ception........................................................ ............................................................... ..97异常的处理办法之一，捕获异常............................................................. . (99)try 块............................................................. ............................................................... ...99catch..................................................... ............................................................... ............99finally.......................................... ............................................................... ....................100try,catch,finally,return执行顺序............................................................. ..................100异常的处理办法之二，声明异常：throw子句............................................................. 101方法重写中声明异常原则............................................................. ......................................102异常的处理办法之三，手动抛出异常，throw子句........................................................103自定义异常............................................................. .. (1)03使用异常机制建议............................................................. ..................................................104总结........................................................................105思考作业............................................................. ............................................................... ...105上机作业............................................................. ............................................................... ...105第五章数组............................................................. ............................................................... . (106)数组概述和特点............................................................. ......................................................106创建数组和初始化............................................................. ..................................................106数组常见操作............................................................. . (108)数组的拷贝............................................................. ......................................................108数组排序............................................................. ..........................................................109多维数组............................................................. ............................................................... ...110附录(面试前复习一下！！)........................................................ (111)冒泡排序.............................................................分法查找............................................................. ......................................................112命令行参数的问题............................................................. ..........................................113增强for循环............................................................. ...................................................114思考作业............................................................. ............................................................... ...114上机作业............................................................. ............................................................... ...115第六章常用类的使用............................................................. (117)基本数据类型的包装类............................................................. (117)包装类基本知识.............................................................. .............................................117包装类的用途.............................................................. .................................................118自动装箱和拆箱？autobo某ing，unbo某ing............................................................. .....119字符串相关类（String、StringBuffer、StringBuilder） (12)String类的常用方法（已讲过，不再讲！）......................................................... .....120StringBuffer和StringBuilder.................................................. ......................................121String和StringBuffer 和StringBuilder使用要点.. (123)5北京尚学堂科技JAVA基础课程时间处理相关类............................................................. (124)Date时间类(java.util.Date)............................................... ...........................................124DateFormat类和SimpleDateFormat 类............................................................. .........125Calendar日历类............................................................. ..............................................126可视化日历的编写............................................................. ..........................................128Math 类............................................................. ............................................................... .....131File 类............................................................. ............................................................... .. (132)为什么需要学习IO技术............................................................. ........................................146基本概念............................................................. ............................................................... (146)数据源.............................................................. . (146)流的概念.............................................................. .........................................................146第一个简单的IO流程序及深入（将文件中的数据读入）.............................................146Java中流的概念细分.............................................................. .............................................148Java中IO流类的体系.............................................................. ...........................................149四个IO基本抽象类.............................................................. .. (150)InputStream.................................................... .. (1)50OutputStream................................................. .. (1)50常用InputStream和OutputStream子类用法 (1)50FileInputStream和FileOutputStream............................................... ...........................150ByteArrayInutStream和ByteArrayOutputStream.......................................... ..........154BufferedInputStream和BufferedOutputStream........................................... ...............156DataInputStream和DataOutputStream............................................... .......................157ObjectInputStream和ObjectOutputStream............................................. ...................158PrintStream.............................. ............................................................... . (158)6北京尚学堂科技JAVA基础课程Reader......................................................... ............................................................... ...158Writer................................................... ............................................................... ..........159FileReader和FileWriter..................................................... ..........................................159BufferReader和BufferWriter................................................... ....................................159InputStreamReader和OutputStreamWriter............................................. ...................161JAVA对象的序列化和反序列化............................................................. .. (161)为什么需要序列化和反序列化...................................................................................161对象的序列化主要有两种用途............................................................. ......................161序列化涉及的类和接口............................................................. ..................................162序列化/反序列化的步骤和实例............................................................. ....................162综合的序列化和反序列化练习............................................................. ......................163JAVA.IO包相关流对象用法总结(尚学堂1002班王鑫).....................................................165IO中其他常用类............................................................. .. (165)File 类............................................................. ............................................................... 165RandomAcceFile.............................................. .. (166)思考作业............................................................. ............................................................... ...166上机作业............................................................. ............................................................... ...166提高课外作业............................................................. ..........................................................166第九章多线程技术............................................................. . (167)念............................................................. ............................................................... (167)程序............................................................. ............................................................... ...167进程............................................................. ............................................................... ...167线程............................................................. ............................................................... ...167线程和进程的区别............................................................. ..........................................167进程与程序的区别............................................................. ..........................................168JAVA中如何实现多线程（重点！！）........................................................ .. (168)通过继承Thread类实现多线程.............................................................. ....................168通过Runnable接口实现多线程.............................................................. ...................169线程状态和leep/yield/join/top/detroy方法.............................................................. (170)态............................................................. ..........................................................170就绪状态............................................................. ..........................................................170运行状态............................................................. ..........................................................170死亡状态............................................................. ..........................................................170终止线程的典型方法（重要！！！）...................................................... .......................171阻塞状态(leep/yield/join方法)............................................................ ......................171线程基本信息和优先级别............................................................. ......................................173线程同步和死锁问题............................................................. ..............................................175死锁及解决方案............................................................. ......................................................179生产者/消费者模式............................................................. ................................................181线程回顾总结............................................................. ..........................................................184任务调度(补充内容，了解即可！).......................................................... ..........................184思考作业............................................................. ..................................................................185上机作业............................................................. ............................................................... ...185第十章网络编程............................................................. .. (1)867北京尚学堂科技JAVA基础课程基本概念............................................................. ............................................................... (186)什么是计算机网络............................................................. ..........................................186计算机网络的主要功能............................................................. ..................................186什么是网络通信协议............................................................. ......................................186网络通信接口............................................................. ..................................................186为什么要分层............................................................. ..................................................186通信协议的分层规定............................................................. ......................................186数据封装............................................................. ..........................................................188数据拆封.......................................................................................................................188IP ............................................................... ............................................................... .. (188)端口............................................................. ............................................................... ...188URL...................................................... ............................................................... .. (189)TCP协议和UDP协议............................................................. (189)区别.............................................................. ................................................................ .189TCP协议.............................................................. ..........................................................189UDP 协议.............................................................. .........................................................190JAVA 网络编程.............................................................. .. (190)InetAddre...................................................... . (19)0InetSocketAddre............................................... .........................................................191URL 类............................................................. .. (1)91基于TCP协议的SOCKET编程和通信............................................................. ...........193UDP通讯的实现............................................................. ..............................................201思考作业............................................................. ............................................................... ...203上机作业（分组完成，3人一组，周末完成）........................................................... .....204第十一章JAVA多媒体编程............................................................. . (205)字体............................................................. ............................................................... .. (205)字体示例和效果............................................................. ..............................................205颜色............................................................. ............................................................... .. (206)颜色编程示例............................................................. ..................................................206图形绘制............................................................. ............................................................... (206)。