start run stop Thread class My Thread extends

二． 编程 start（）启动线程 run（）线程体，线程的实现 stop（）停止线程 １． 继承Thread class My. Thread extends. Thread { public void run() { 线程体； } public static void main(String s[]) { My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); mt 1. start(); mt 2. start(); } } 2． 实现Runnable接口 class My. Thread implements Runnable { public void run() { 线程体； } public static void main(String s[]) {My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); Thread t 1=new Thread(mt 1); Thread t 2=new Thread(mt 2); t 1. start(); t 2. start(); } }

四． 线程的方法 Thread. current. Thread() set. Name() get. Name() set. Priority() get. Priority() Daemon: set. Daemon(true) 设置为后台线程 set. Daemon(false) 设置为应用线程

五． 例子 public class My. Thread extends Thread { private int count=0; public void set. Count() { count++; } public void run() { for (int i=0; i<10; i++) { set. Count(); System. out. println(Thread. current. Thread(). get. Name()+": "+count); } } public static void main(String[] args) { My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); mt 1. set. Name("MT 1"); mt 2. set. Name("MT 2"); mt 1. start(); mt 2. start(); } }

五． 例子 public class My. Thread extends Thread { private static int count=0; public void set. Count() { count++; } public void run() { for (int i=0; i<10; i++) { set. Count(); System. out. println(Thread. current. Thread(). get. Name()+": "+count); } } public static void main(String[] args) { My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); mt 1. set. Name("MT 1"); mt 2. set. Name("MT 2"); mt 1. start(); mt 2. start(); } }

六. 线程同步 public void push(char c) { data[idx]=c; idx++; } public char pop() { idx--; return data[idx]; }

二． 常用流类 1. 字节流 File. Input. Stream / File. Output. Stream Buffered. Input. Stream / Buffered. Output. Stream Data. Input. Stream / Data. Output. Stream Piped. Input. Stream / Piped. Output. Stream 例: File. Input. Stream fis=new File. Input. Stream(“aa. doc”); Buffered. Input. Stream bis=new Buffered. Input. Stream(fis); Data. Input. Stream dis=new Data. Input. Stream(bis);

2. 字符流-16位版本的数据流 Input. Stream. Reader / Output. Stream. Writer 用于字节流 字符流的转换 Buffered. Reader / Buffered. Writer

3. 例: 从标准输入中读取字符串数据 import java. io. *; public class Input { public static void main(String[] args) { String s; Input. Stream. Reader ir; Buffered. Reader br; ir=new Input. Stream. Reader(System. in); br=new Buffered. Reader(ir); try { while((s=br. read. Line())!=null) { System. out. println("Read: "+s); } }catch(IOException e) { System. out. println("Read falled"); } } }

三． URL输入流 提供了使用统一资源定位符URL在网络上访问对象的方法. 隐含使用URL对象: image=get. Image(get. Document. Base(), ”t 1. gif”); 直接使用URL对象: URL image. Source=new URL(“http: //……”); image=get. Image(image. Source, ”t 1. gif”);

二． 编程 start（）启动线程 run（）线程体，线程的实现 １． 继承Thread class My. Thread extends. Thread { public void run() { 线程体； } public static void main(String s[]) { My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); Mt 1. start(); Mt 2. start(); } } 2． 实现Runnable接口 class My. Thread implements Runnable { public void run() { 线程体； } public static void main(String s[]) {My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); Thread t 1=new Thread(mt 1); Thread t 2=new Thread(mt 2); t 1. start(); t 2. start(); } }

１． New Thread状态 Thread my. Thread=new Thread. Class() 2. Runnable状态 Thread my. Thread=new Threadclass(); My. Thread. start();

3. Not Runnable状态 n n n sleep（） wait（） I/O动作时

六． 线程的方法 current. Thread() set. Name() get. Name() set. Priority() get. Priority() is. Alive（） yield（） set. Daemon(true) is. Daemon()

七． 例子 public class My. Thread extends Thread { private int count=0; public void set. Count() { count++; } public void run() { for (int i=0; i<10; i++) { set. Count(); System. out. println(Thread. current. Thread(). get. Name()+": "+count); } } public static void main(String[] args) { My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); mt 1. set. Name("MT 1"); mt 2. set. Name("MT 2"); mt 1. start(); mt 2. start(); } }

五． 例子 public class My. Thread extends Thread { private static int count=0; public void set. Count() { count++; } public void run() { for (int i=0; i<10; i++) { set. Count(); System. out. println(Thread. current. Thread(). get. Name()+": "+count); } } public static void main(String[] args) { My. Thread mt 1=new My. Thread(); My. Thread mt 2=new My. Thread(); mt 1. set. Name("MT 1"); mt 2. set. Name("MT 2"); mt 1. start(); mt 2. start(); } }

八. 线程同步 问题的引出： public void push(char c) { date[idx]=c; idx++; } public pop() { idx--; return date[idx]; }

解决方法： synchronized关键字

标准输出(System. out) n n System. out. print(“Hello World”); //print System. out. println(“Hello World”); //print line

标准输入(System. in) public class P { public static void main(String[] args) { int key. Input; int i=0; try{ while((key. Input=System. in. read())!=-1){ i++; System. out. println(i+"="+key. Input); } } catch(IOException e){} } }

标准错误(System. err) n 把错误信息显示给用户 System. err. println(“Warning!”);

2. 常用的I/O流 n File. Input. Stream/File. Output. Stream n Pipe. Input. Stream/Pipe. Output. Stream n Byte. Array. Input. Stream/ Byte. Array. Output. Stream n Sequence. Input. Stream n String. Buffer. Input. Stream

3. 过滤流 Filter. Input. Stream/Filter. Output. Stream

三． URL输入流 提供了使用统一资源定位符URL在网络上访 问对象的方法. 隐含使用URL对象: image=get. Image(get. Document. Base(), ”t 1. gif ”); 直接使用URL对象: URL image. Source=new URL(“http: //……”); image=get. Image(image. Source, ”t 1. gif”);

1. 定义一个日期类Date class Date { private int year=1990, month=1, day=1; public Date(){} public Date(int year, int month, int day) { this. year=year; this. month=month; this. day=day; } public Date(int year) { this(year, 1, 1); } public Date(Date d) { this (d. year, d. month, d. day); } public String get. Date() { return year+"/"+month+"/"+day; } public void set. Date(int year, int month, int day) { this. year=year; this. month=month; this. day=day; } public void set. Date(int month, int day) { set. Date(this. year, month, day); } } class Ex 3 { public static void main(String[] args) { Date d 1=new Date(); System. out. println(d 1. get. Date()); Date d 2=new Date(2000, 11, 17); System. out. println(d 2. get. Date()); Date d 3=new Date(2010); System. out. println(d 3. get. Date()); Date d 4=new Date(d 2); System. out. println(d 4. get. Date()); Date d 5=d 2; System. out. println(d 5. get. Date()); } }

1. class Point{ int x, y; public static void main(String args[]){ switch(args. length){ case 0: Point p=new Point(); p. display(); break; case 1: Point p 1=new Point(Integer. parse. Int(args[0])); p 1. display(); break; case 2: Point p 2=new Point(Integer. parse. Int(args[0]), Integer. parse. Int(args[1])); p 2. display(); break; default: System. out. println(“the arguments too long”); } //switch

public Point(int x, int y){ this. x=x; this. y=y; } public Point(int x){ this(0, x); } public Point(){ this(0); } public void display(){ System. out. println("("+x+", "+y+")"); } } //class

2. class Multiply { public static void main(String args[]) { Multiply m=new Multiply(); m. ply(Integer. parse. Int(args[0])); } public void ply (int i) { int s=1; for (int j=i; j>0; j--) {s*=j; } System. out. println(s); } }

六. 例程(对继承) class Ex 4 class Person { public static void main(String s[]) { private String name; { Person p 1=new Person("Zhao", true); private boolean sex; p 1. get. Detail(); public Person(String name, boolean sex) Teacher t 1=new Teacher("Qian", false, 1); { this. name=name; t 1. get. Detail(); this. sex=sex; } Person p[]=new Person[5]; public void get. Detail() p[0]=new Teacher("Sun", true, 2); { System. out. println(name+sex); } p[1]=new Student("Li", true, 2); } p[2]=new Teacher("Zhou", true, 2); class Teacher extends Person p[3]=new Student("Wu", true, 2); { private int department; p[4]=new Teacher("Zheng", true, 2); public Teacher(String name, boolean sex, int depart) for (int i=0; i<p. length; i++) { super(name, sex); { if(p[i] instanceof Teacher) department=depart; } { System. out. println("Teacher"); public void get. Detail() p[i]. get. Detail(); } { super. get. Detail(); else if (p[i] instanceof Student) System. out. println(department); { System. out. println("student"); } Student s 1=(Student)p[i]; } s 1. get. Detail(); } class Student extends Person } { 同Teacher department-->classes } depart-->cls } }

import java. awt. *; …… public class Calculator pan. add(new Button("/")); { Frame f; f. set. Size(200, 200); Panel pan; f. set. Visible(true); } public Calculator () public static void main(String s[]) { f=new Frame("Calculator"); { pan=new Panel(); } c. go(); public void go() { f. add("North", new Text. Field("")); f. add("Center", pan); pan. set. Layout(new Grid. Layout(4, 4)); pan. add(new Button("1")); pan. add(new Button("2")); pan. add(new Button("+")); Calculator c=new Calculator (); } }