JDK1.5新特性总结

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JDK1.5新特性：

1、  自动装箱与拆箱

Integer iobj=2;

System.out.println(iobj+12);

Integer i1=145;

Integer i1=145;

System.out.println(i1==i2);//false,

 

Integer i3=Integer.valueof(126);

Integer i4=Integer.valueof(126);

System.out.println(i3==i4);//true,

//主要原因是由于Integer采用的是享元模式

 

2、  枚举

public static void main(String[] args)

{

WeekDay weekDay1=WeekDay.MON;

System.out.println(weekDay1.nextDay());

WeekDay weekDay2=WeekDay.FRI;

System.out.println(weekDay2);

}

public enum WeekDay{

SUN(1),MON,TUE,WED,THI,FRI,SAT;

private WeekDay(){System.out.println(“first”);}

private WeekDay(int day){System.out.println(“second”);}

}

3.静态导入

import static java.lang.Math.*;

 

public class StaticImport{

public static void main(String[] args){

  int x=1;

  try{

x++;

}finally{

System.out.println(“template”);

}

System.out.println(x);

System.out.println(max(3,5));

System.out.println(max(3,-9));

}

}

4、  可变参数

public class VarableParameter{

public static void main(String[]args)

{

System.out.println(add(2,3));

System.out.println(add(2,3,5));

}

public static int add(int x,int …args){

int sum=x;

for(int arg:args){

sum+=arg;

}

return sum;

}

}

5、  內省

ReflectPoint pt=new ReflectPoint(3,5);

BeanInfo beanInfo=Introspector.getBeanInfo(pt.getClass());

PropertyDescriptor[]pds=beanInfo.getPropertyDescriptors();

Object retVal=null;

for(PropertyDescriptor pd:pds)

{

Method methodget=pd.getReadMethod();

retVal=methodget.invoke(pt);

}