f.txt

清华本科全套java课件 经典不用多说

-------------------------1---------------
class Count {
      private int serial ;
      private static int counter = 0 ;
      Count() {
          counter++;
          serial = counter ;
      }
      int getserial(){ return serial ;}
    }

class StaticVar {
      static int  x = 100 ;
  }

public  class test {
  public static void main(String[] args){
   Count c1 = new Count();
   Count c2 = new Count();
   System.out.println(c1.getserial());          
   System.out.println(c2.getserial());   

   System.out.println(StaticVar.x++);
   System.out.println(StaticVar.x++);
   System.out.println("E=  " + Math.E);
   System.out.println("PI=  " + Math.PI);
  }
}

-------------------------2------------------------
public class e43 
{
public static void main(String args[])
{
	PhoneCard200 my200_1 = new PhoneCard200();
	PhoneCard200 my200_2 = new PhoneCard200();
    PhoneCard200.additoryFee = 0.1;
    System.out.println("第1张200卡的附加费："+my200_1.additoryFee);
    System.out.println("第2张200卡的附加费："+my200_2.additoryFee);
	System.out.println("200卡类的附加费："+PhoneCard200.additoryFee);

	System.out.println("200卡接入号码:" + PhoneCard200.connectNumber);
    System.out.println("第1张200卡的接入号码:" + my200_1.connectNumber);
	}
}
class PhoneCard200
{
    static  final String  connectNumber = "200";
	static  double  additoryFee;
	long  cardNumber ;
	int  password;
	boolean connected;
	double  balance;
}
---------------------3----------------------
public class a {
  public static void main(String[] args){
    System.out.println(Math.round(3.54));

    String s = to_char(2.718);
    System.out.println("e=" + s);
  }

  static String to_char(double x){
    return Double.toString(x);
  }
}
--------------------4--------------------
public class e44
{
public static void main(String args[])
{
	PhoneCard200 my200_1 = new PhoneCard200();
	PhoneCard200 my200_2 = new PhoneCard200();
	System.out.println("第一张200卡的卡号："+my200_1.cardNumber);
	System.out.println("第二张200卡的卡号："+my200_2.cardNumber);
}
}
class PhoneCard200
{
	static  long  nextCardNumber;
	static  String  connectNumber = "200";
	static  double  additoryFee;
	long  cardNumber ;
	int  password;
	boolean connected;
	double  balance;

	static
	{
		nextCardNumber = 2001800001;
	}
	PhoneCard200()
	{
		cardNumber = nextCardNumber++;
	}
}
--------------------5----------------------

//建立包，加入类
package mypk ;
public class A{
  public void print(String s){
    B b1 = new B();
    System.out.println(b1.addString(s) );
  }
}
class B{
  String addString(String s){
    return "-----" + s + "-----" ;
  }
}
//javac -d d:\ A.java 将 mypk包 建在d:\目录下
//测试程序
import mypk.* ;
public class test{
 public static void main(String[] args){
  A a1 = new A();
  a1.print("test");
 }
}
//将d:\目录追加到classpath环境变量中
// javac test.java
// java test
---------------------6---------------------
package mypk ;

public class pubclass  {
   private String a1="private";
   String a2="package";
   protected String a3="protected";
   public String a4="public";

   private String get1(){
      return "privateMethod " + a1 ;
   } 
   String get2(){
      return "packageMethod " + a1 ;
   } 
   protected String get3(){
      return  "protectedMethod " + a1;
   } 
   public String get4(){
      return "publicMethod " + a1 ;
   }
}
class nopubclass
{  public int x=1;
   public int getx(){
     return x ;
   }
}
//-------
//测试访问其他包中的类
import mypk.* ;

class test1 {
  public static void main(String args[]) {
    pubclass pc =new pubclass();           // 建立mypk包的public类对象
    System.out.println(pc.a1+pc.a2+pc.a3+pc.a4);  
    System.out.println(pc.a4);  

    System.out.println(pc.get1()+pc.get2()+pc.get3()+pc.get4());
    System.out.println(pc.get4());

    nopubclass nopubc=new nopubclass();    // 建立mypk包的非public类对象  
  }
}
//-----------测试子类继承其他包中的-------------
import mypk.* ;

class test2
{
  public static void main(String args[])
 {
      subClass sc= new subClass();
      System.out.println(sc.geta());
      System.out.println(sc.a3 + sc.a4);     
  }
}
class subClass extends pubclass {    
   String geta() {
       return   a1+a2+a3+a4 ;
  }
}

--------------------7------------------
interface CalArea { 
    double pi = 3.14 ;
    double cal(double r); 
}
class a  implements CalArea {
    double cal(double r) {            //
      return pi * r *r  ;
   }
}

public class test {
 public static void main(String[] args){
   a a1 = new a() ;
   System.out.println(a1.cal(5.0));
   System.out.println(a1 instanceof CalArea );
 }
}
------------- parcel2.java     在类中定义内层类-------
public class Parcel2 {
  class Contents {                    //inner class 1
    private int i ;
    Contents(int cn){ i=cn;}
    public int value() { return i; }
  }
  class Destination {                 //inner class 2
    private String label;
    Destination(String whereTo) {label = whereTo; }
    String readLabel() { return label; }
  }
  public Destination to(String s) {     //method 1
    return new Destination(s);
  }
  public Contents cont(int cn) {              //method 2
    return new Contents(cn); 
  }
  public void ship(String dest,int cn) {       //method 3
    Contents c = cont(cn);
    Destination d = to(dest);
    System.out.println("Contents:  " + c.value());
    System.out.println("Distination:  " + d.readLabel()); 
  }  
} 
class pl2 {
  public static void main(String[] args) {
    Parcel2 p1 = new Parcel2();
    p1.ship("Tanzania",100);

    Parcel2.Contents cc = p1.new Contents(1010);
    System.out.println(cc.value());

    Parcel2 p2 = new Parcel2();
    Parcel2.Contents c = p2.cont(200); // return handles to inner classes
    Parcel2.Destination d = p2.to("Borneo"); 
    System.out.println(c.value());
    System.out.println(d.readLabel());
  }
} 


-----parcel3.java  内层类实现接口和基类的抽象方法-------
abstract class Contents {                   //不一定是抽象类
  abstract public int value();   
}

interface Destination {                     //典型应用
  String readLabel();
}

public class Parcel3 {
  private class PContents extends Contents {
    private int i ;
    PContents(int cn){i=cn;}
    public int value() { return i; }     //method overriding
  }
  protected class PDestination implements Destination {
    private String label;
    private PDestination(String whereTo) {
      label = whereTo;
    }
    public String readLabel() { return label; }  //implement method
  }
  public Destination dest(String s) {
    return new PDestination(s);
  }
  public Contents cont(int cn) { 
    return new PContents(cn); 
  }
}

class pl3 {
  public static void main(String[] args) {
    Parcel3 p = new Parcel3();   
    Contents c = p.cont(100);                   //upcast
    Destination d = p.dest("Tanzania");      //upcast
    System.out.println(c.value());
    System.out.println(d.readLabel());

    // Illegal -- can't access private class:
    //! Parcel3.PContents c = p.new PContents();
  }
}

---------parcel4.java   在方法中定义内层类------------
interface Destination {
  String readLabel();
} 

public class Parcel4 {                    // Parcel4类
  public Destination dest(String s) {     // dest方法
    class PDestination
        implements Destination {
      private String label;
      private PDestination(String whereTo) {
        label = whereTo;
      }
      public String readLabel() { return label; }  //重载
    }
    return new PDestination(s);
  }
} 
class pl4 {
  public static void main(String[] args) {
    Parcel4 p = new Parcel4();
    Destination d = p.dest("Tanzania");        // 提供处理句柄
    System.out.println(d.readLabel());
  }
} 

----- parcel5.java  在语句（条件语句分支）中定义内层类-----
public class Parcel5 {
  void internalTracking(boolean b) {
    if(b) {
      class TrackingSlip {
        private String id;
        TrackingSlip(String s) {
          id = s;
        }
        String getSlip() { return id; }
      }
      TrackingSlip ts = new TrackingSlip("slip");
      String s = ts.getSlip();
      System.out.println(s);
    }
    // Can't use it here! Out of scope:
    //! TrackingSlip ts = new TrackingSlip("x");
  }
}

class pl5 {
  public static void main(String[] args) {
    Parcel5 p = new Parcel5();
    p.internalTracking(true);
  }
} 

//在条件语句中的内部类 TrackingSlip并不表示有条件的建立
//同其他类一样，在编译时就一道解决了。
//内部类只是限定它的作用域（在条件分支中使用）。


-------- parcel6.java    实现接口的内层匿名类 --------
//-------无名内层类--------------
interface Contents {
  int value();
} 
public class Parcel6 {
  public Contents cont() {
    return new Contents() {
      private int i = 11;
      public int value() { return i; }
    };   // 此处要冒号
  }
}

class pl6 {
  public static void main(String[] args) {
    Parcel6 p = new Parcel6();
    Contents c = p.cont();
    System.out.println(c.value());
  }
}