java.util.zip.ZipException：无效的通用标志位：9

Question

我得到这个错误在Android 6.0

java.util.zip.ZipException: Invalid General Purpose Bit Flag: 9 java.util.zip.ZipInputStream.getNextEntry(ZipInputStream.java:253)

这是我的代码：

ZipInputStream zin = new ZipInputStream(getAppContext().getContentResolver().openInputStream(uri)); 

是什么意思？我究竟做错了什么？

Answer 1

这里的ZIP文件规范：

Flags General purpose bit flag: 
Bit 00: encrypted file 
Bit 01: compression option 
Bit 02: compression option 
Bit 03: data descriptor 
Bit 04: enhanced deflation 
Bit 05: compressed patched data 
Bit 06: strong encryption 
Bit 07-10: unused 
Bit 11: language encoding 
Bit 12: reserved 
Bit 13: mask header values 
Bit 14-15: reserved 

所以，9:1的GPBF值既具有“加密文件”，并设置“数据描述符”位。

在Android源代码这里一个偷看： https://chromium.googlesource.com/android_tools/+/9e9b6169a098bc19986e44fbbf65e4c29031e4bd/sdk/sources/android-22/java/util/zip/ZipFile.java （旧版本，但我怀疑这并没有改变）显示了这一点：

static final int GPBF_ENCRYPTED_FLAG = 1 << 0; 

[...]

/** 
* Supported General Purpose Bit Flags Mask. 
* Bit mask of bits not supported. 
* Note: The only bit that we will enforce at this time 
* is the encrypted bit. Although other bits are not supported, 
* we must not enforce them as this could break some legitimate 
* use cases (See http://b/8617715). 
*/ 
static final int GPBF_UNSUPPORTED_MASK = GPBF_ENCRYPTED_FLAG; 

[...]

// At position 6 we find the General Purpose Bit Flag. 
int gpbf = Short.reverseBytes(is.readShort()) & 0xffff; 
if ((gpbf & ZipFile.GPBF_UNSUPPORTED_MASK) != 0) { 
    throw new ZipException("Invalid General Purpose Bit Flag: " + gpbf); 
} 

所以，你的ZIP文件CL旨在对文件进行加密（设置GPBF的位00），并且ZipFile实现不支持读取加密文件。