不同语言的base64字符串的解码值给出不同的输出

我有一个像这样的base64字符串

String value = "fefWUeQvPgBe/9QaG/RdPnn9PrzQK2VhVwBzAIr7eei9PQrZA2/sXTA/2SCodnTSJn4Lk+ve5kuPGjco4ljYrjNTsrKBAjN6APSHn0BqBce2lOZbm/z29U6j7j79niPbYl/UIc0VTjc0IgRhmNLn1eVvMTuoaGhlwlxUf/+xenC4NmEM2A6y5/DNRheNw6OrmHik/kowpWGQsRNFyXJ2VtzE54nqs9naePBkRlWna/oqBxzA/txtHXn8h/9xTT2caozcU5/R9JayFZq7ZeclzGs2DAACr1TyQwEb9JJpBXr04Zu4rlWLtnSbyflyK3lnSAocma0L6ENnCZoMiN8gUg=="

我用这个方法在java中解码字符串

Base64Utils.decode(value.getBytes())
output:125,-25,-42,81,-28,47,62,0,94,-1,-44,26,27,-12,93,62,121,-3,62,-68,-48,43,101,97,87,0,115,0,-118,-5,121,-24,-67,61,10,-39,3,111,-20,93,48,63,-39,32,-88,118,116,-46,38,126,11,-109,-21,-34,-26,75,-113,26,55,40,-30,88,-40,-82,51,83,-78,-78,-127,2,51,122,0,-12,-121,-97,64,106,5,-57,-74,-108,-26,91,-101,-4,-10,-11,78,-93,-18,62,-3,-98,35,-37,98,95,-44,33,-51,21,78,55,52,34,4,97,-104,-46,-25,-43,-27,111,49,59,-88,104,104,101,-62,92,84,127,-1,-79,122,112,-72,54,97,12,-40,14,-78,-25,-16,-51,70,23,-115,-61,-93,-85,-104,120,-92,-2,74,48,-91,97,-112,-79,19,69,-55,114,118,86,-36,-60,-25,-119,-22,-77,-39,-38,120,-16,100,70,85,-89,107,-6,42,7,28,-64,-2,-36,109,29,121,-4,-121,-1,113,77,61,-100,106,-116,-36,83,-97,-47,-12,-106,-78,21,-102,-69,101,-25,37,-52,107,54,12,0,2,-81,84,-14,67,1,27,-12,-110,105,5,122,-12,-31,-101,-72,-82,85,-117,-74,116,-101,-55,-7,114,43,121,103,72,10,28,-103,-83,11,-24,67,103,9,-102,12,-120,-33,32,82,

然后我使用这个方法来解码nodejs中的字符串

Buffer.from(value, 'base64')
output:125,231,214,81,228,47,62,0,94,255,212,26,27,244,93,62,121,253,62,188,208,43,101,97,87,0,115,0,138,251,121,232,189,61,10,217,3,111,236,93,48,63,217,32,168,118,116,210,38,126,11,147,235,222,230,75,143,26,55,40,226,88,216,174,51,83,178,178,129,2,51,122,0,244,135,159,64,106,5,199,182,148,230,91,155,252,246,245,78,163,238,62,253,158,35,219,98,95,212,33,205,21,78,55,52,34,4,97,152,210,231,213,229,111,49,59,168,104,104,101,194,92,84,127,255,177,122,112,184,54,97,12,216,14,178,231,240,205,70,23,141,195,163,171,152,120,164,254,74,48,165,97,144,177,19,69,201,114,118,86,220,196,231,137,234,179,217,218,120,240,100,70,85,167,107,250,42,7,28,192,254,220,109,29,121,252,135,255,113,77,61,156,106,140,220,83,159,209,244,150,178,21,154,187,101,231,37,204,107,54,12,0,2,175,84,242,67,1,27,244,146,105,5,122,244,225,155,184,174,85,139,182,116,155,201,249,114,43,121,103,72,10,28,153,173,11,232,67,103,9,154,12,136,223,32,82

java输出是我真正想要的，为什么不同

---

如何正确获取nodejs中的解码值

Base64Utils。decode

在Java中返回有符号的8位值

Buffer.from

返回Nodejs中的无符号8位值。虽然两者都返回8位（字节）值，但Java方法将高位解释为负数。Nodejs没有签名

Buffer.from(value, 'base64')
output:125,231,214,81,228,47,62,0,94,255,212,26,27,244,93,62,121,253,62,188,208,43,101,97,87,0,115,0,138,251,121,232,189,61,10,217,3,111,236,93,48,63,217,32,168,118,116,210,38,126,11,147,235,222,230,75,143,26,55,40,226,88,216,174,51,83,178,178,129,2,51,122,0,244,135,159,64,106,5,199,182,148,230,91,155,252,246,245,78,163,238,62,253,158,35,219,98,95,212,33,205,21,78,55,52,34,4,97,152,210,231,213,229,111,49,59,168,104,104,101,194,92,84,127,255,177,122,112,184,54,97,12,216,14,178,231,240,205,70,23,141,195,163,171,152,120,164,254,74,48,165,97,144,177,19,69,201,114,118,86,220,196,231,137,234,179,217,218,120,240,100,70,85,167,107,250,42,7,28,192,254,220,109,29,121,252,135,255,113,77,61,156,106,140,220,83,159,209,244,150,178,21,154,187,101,231,37,204,107,54,12,0,2,175,84,242,67,1,27,244,146,105,5,122,244,225,155,184,174,85,139,182,116,155,201,249,114,43,121,103,72,10,28,153,173,11,232,67,103,9,154,12,136,223,32,82

var值='fefWUeQvPgBe/9QaG/rdpnn9przqk2vwbzair\
7eei9PQrZA2/sXTA/2SCodnTSJn4Lk+ve5kuPGj\
co4ljYrjNTsrKBAjN6APSHn0BqBce2lOZbm/z29\
U6j7j79niPbYl/UIC0VTJC0IGRHMNLN1 VVMTUO\
aGhlwlxUf/+xenC4NmEM2A6y5/DNRheNw6OrmHi\
k/kowpWGQsRNFyXJ2VtzE54nqs9naePBkRlWna/\
oqBxzA/txtHXn8h/9xTT2caozcU5/R9JayFZq7Z\
eclzGs2DAACr1TyQwEb9JJpBXr04Zu4rlWLtnSb\
yflyK3lnSAocma0L6ENnCZoMiN8gUg=='
buffervalue=Buffer.from（值'base64'）；
对于（i=0；i127）{
y=-（256-y）；
}
控制台日志（y）；
}