java Object转Integer实现方式

Object obj = 42; // 假设这是一个 Integer 对象
if (obj instanceof Integer) {
    Integer intObj = (Integer) obj;
    System.out.println("Converted value: " + intObj);
} else {
    System.out.println("Object is not an Integer");
}

Object obj = "42"; // 假设这是一个 String 对象
try {
    Integer intObj = Integer.valueOf(obj.toString());
    System.out.println("Converted value: " + intObj);
} catch (NumberFormatException e) {
    System.out.println("Object cannot be converted to Integer");
}

Object obj = 42; // 或者 "42"
Integer intObj = null;

if (obj instanceof Integer) {
    intObj = (Integer) obj;
} else if (obj instanceof String) {
    try {
        intObj = Integer.valueOf((String) obj);
    } catch (NumberFormatException e) {
        System.out.println("String cannot be converted to Integer");
    }
} else {
    System.out.println("Object is not convertible to Integer");
}

if (intObj != null) {
    System.out.println("Converted value: " + intObj);
}

public class ObjectToIntegerConversion {
    public static void main(String[] args) {
        Object obj1 = 42;      // Integer 对象
        Object obj2 = "42";    // String 对象
        Object obj3 = 3.14;    // 其他类型对象

        convertAndPrint(obj1);
        convertAndPrint(obj2);
        convertAndPrint(obj3);
    }

    public static void convertAndPrint(Object obj) {
        Integer intObj = null;

        if (obj instanceof Integer) {
            intObj = (Integer) obj;
        } else if (obj instanceof String) {
            try {
                intObj = Integer.valueOf((String) obj);
            } catch (NumberFormatException e) {
                System.out.println("String cannot be converted to Integer: " + obj);
            }
        } else {
            System.out.println("Object is not convertible to Integer: " + obj);
        }

        if (intObj != null) {
            System.out.println("Converted value: " + intObj);
        }
    }
}