Java全面细致讲解Wrapper的使用

int i = 500; 
Integer t = new Integer(i);

Float f = new Float(“4.56”);
//Long l = new Long(“asdf”); 报错：NumberFormatException

Integer in3 = new Integer("123abc");
System.out.println(in3.toString());
/*  
报错：
Exception in thread "main" java.lang.NumberFormatException: For input string: "123abc"
 */

boolean b = bObj.booleanValue();

    int i = new Integer(“12”);

Float f = Float.parseFloat(“12.1”);

int num1 = (int)str1;
Integer in1 = (Integer)str1;
//可能会报NumberFormatException

   String fstr = String.valueOf(2.34f);

   String intStr = 5 + "";

//(1)
     Object o1 = true ? new Integer(1) : new Double(2.0);
     System.out.println(o1);//1.0
     Object o2;
        if (true)
            o2 = new Integer(1);
        else
            o2 = new Double(2.0);
        System.out.println(o2);//1
    }
//(2)
//java
        Integer i = new Integer(1);
        Integer j = new Integer(1);
        System.out.println(i == j);//false
        Integer m = 1;
        Integer n = 1;
        System.out.println(m == n);//true
        Integer x = 128;
        Integer y = 128;
        System.out.println(x == y);//false