* This method will always cache values in the range -128 to 127, * inclusive, and may cache other values outside of this range. * * @param i an {@code int} value. * @return an {@code Integer} instance representing {@code i}. * @since 1.5 */ public static Integer valueOf(int ...
This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range. 此⽅法将始终缓存-128到127（包括端点）范围内的值，并可以缓存此范围之外的其他值 缓存设计 valueOf ⽅法中 IntegerCache.low = -128； IntegerCache.high = 127 ; 也就...
// high value may be configured by property int h = 127; String integerCacheHighPropValue = sun.misc.VM.getSavedProperty("java.lang.Integer.IntegerCache.high"); if (integerCacheHighPropValue != null) { try { int i = parseInt(integerCacheHighPropValue); i = Math.max(i, 127); // Maxim...
对于integer类型使用==比较大小实际调用了`Integer valueOf`方法,源码如下: public static Integer valueOf(int var0) { return var0 >= -128 && var0 <= Integer.IntegerCache.high ? Integer.IntegerCache.cache[var0 + 128] : new Integer(var0); } 就是说如果参数大于等于-128并且小于等于Integer.Integer...
* This method will always cache values in the range -128 to 127, * inclusive, and may cache other values outside of this range. * * @param i an {@code int} value. * @return an {@code Integer} instance representing {@code i}. ...
Integer只有一个非静态字段value,用来表示其包装的int值。0x80000000和0x7fffffff分别是 int 最小值和最大值的十六进制表示,这里要注意十六进制 int 值在内存中的表示方法,有兴趣的同学可以了解一下,这里先占个坑,有时间单独写[一篇文章]()。 我们都知道int是 4 字节,32 比特,和 C/C++ 不同的时,Java中整型...
在JavaAPI中是这样解释的: Returns an Integer instance representing the specified int value. If a new Integer instance is not required, this method should generally be used in preference to the constructor Integer(int), as this method is likely to yield significantly better space and time performan...
1 Integer.valueOf() 整形的赋值操作底层其实是调用了 Integer.valueOf(num) 方法。 所以, Integer a = 888 这句代码其实等价于: Integer a = Integer.valueOf(888); 来看看 Integer.valueOf 的代码实现: /*** This method will always cache values in the range -128 to 127,* inclusive, and may...
The string is converted to an int value in exactly the manner used by the parseInt method for radix 10. Parameters: s - the String to be converted to an Integer. Throws: NumberFormatException - if the String does not contain a parsable integer. See Also: parseInt(java.lang.String, int)...
// high value may be configured by property int h = 127; String integerCacheHighPropValue = VM.getSavedProperty("java.lang.Integer.IntegerCache.high"); if (integerCacheHighPropValue != null) { try { int i = parseInt(integerCacheHighPropValue); ...