Integer 源码 private static class IntegerCache { static final int low = -128; static final int high; static final Integer cache[]; 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); }Integer 缓存-128 ~ 127 之间的数字,范围外的就只能去new了
static final int low = -128;
static final int high;
static final Integer cache[]; 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);
}Integer 缓存-128 ~ 127 之间的数字,范围外的就只能去new了