详谈java中int和Integer的区别及自动装箱和自动拆箱

//程序如下所示
int a = 10;
int b = 10;
Integer c = 10;
Integer d = 10;
Integer e = new Integer(10);
Integer f = new Integer(10);
Integer g = 1000;
Integer h = 1000;
		
System.out.println("int和int比较值：-----" + (a == b));
System.out.println("int和Integer比较值：-----" + (a == c));
System.out.println("Integer和Integer小于128比较值：-----" + (c == d));
System.out.println("Integer和New Integer()比较值：-----" + (c == e));
System.out.println("New Integer()和New Integer()比较值：-----" + (f == e));
System.out.println("Integer和Integer大于127比较值：-----" + (g == h));
System.out.println("int和New Integer()比较值：-----" + (a == e));

Integer i = 100;    //自动装箱，类似于Integer i = Integer.valueOf(100);
int j = i;          //自动拆箱，类似于int j = i.intValue();

package integerdemo; 
public class IntegerDemo {  
    public static void main(String[] args) {
       //-128--127之间
        Integer i1 = 100;
        Integer i2 = 100;
        
        if( i1 == i2){
            System.out.println("i1 == i2");
        }else{
            System.out.println("i1 != i2 ");
        }
        
       //大于127  
        Integer i3 = 200;
        Integer i4 = 200;
        
        if( i3 == i4){
            System.out.println("i3 == i4");
        }else{
            System.out.println("i3 != i4 ");
        }        
    }
}

  public static Integer valueOf(int i) {
        assert IntegerCache.high >= 127;
        if (i >= IntegerCache.low && i <= IntegerCache.high)
            return IntegerCache.cache[i + (-IntegerCache.low)];
        return new Integer(i);
    }