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尝试在Android中创建应用校验和,但没有改变

checksum apk android java

TheGribble · 技术社区 · 7 年前

我正在尝试这个,公然从 https://www.programcreek.com/java-api-examples/index.php?class=java.util.zip.CheckedInputStream&method=read :

String apkPath = App.getContext().getPackageCodePath();
Log.i("Checksum", "getting checksum for " + apkPath);
Long chksum = null;
Log.i("Checksum", "Size: " + new File(apkPath).length());
Log.i("Checksum", "Date: " + new Date(new File(apkPath).lastModified()));

try {
    // Open the file and build a CRC32 checksum.
    FileInputStream fis = new FileInputStream(new File(apkPath));
    CRC32 chk = new CRC32();
    CheckedInputStream cis = new CheckedInputStream(fis, chk);
    byte[] buff = new byte[80];
    while (cis.read(buff) >= 0) ;
    chksum = chk.getValue();
} catch (Exception e) {
    e.printStackTrace();
}
Log.i("Checksum", "Checksum is  " + chksum);

运行良好,输出良好:

09-27 15:17:35.775 17288-17288/com.test.checksum.checksum I/Checksum: getting checksum for /data/app/com.test.checksum.checksum-2/base.apk
09-27 15:17:35.775 17288-17288/com.test.checksum.checksum I/Checksum: Size: 3245610
09-27 15:17:35.775 17288-17288/com.test.checksum.checksum I/Checksum: Date: Wed Sep 27 15:17:03 BST 2017
09-27 15:17:37.075 17288-17288/com.test.checksum.checksum I/Checksum: And Checksum is  0DAD53E0

问题是,更改代码似乎没有任何区别-因此,以下代码:

String apkPath = App.getContext().getPackageCodePath();
Log.i("Checksum", "getting checksum for " + apkPath);
Long chksum = null;
Log.i("Checksum", "Size: " + new File(apkPath).length());
Log.i("Checksum", "Date: " + new Date(new File(apkPath).lastModified()));

//do something differently
Log.i("Checksum", "And now do something else!");
Toast toast = Toast.makeText(getApplicationContext(), "I'm doing something else!", Toast.LENGTH_SHORT);
toast.show();

try {
    // Open the file and build a CRC32 checksum.
    FileInputStream fis = new FileInputStream(new File(apkPath));
    CRC32 chk = new CRC32();
    CheckedInputStream cis = new CheckedInputStream(fis, chk);
    byte[] buff = new byte[80];
    while (cis.read(buff) >= 0) ;
    chksum = chk.getValue();
} catch (Exception e) {
    e.printStackTrace();
}
Log.i("Checksum", "Checksum is  " + String.format("%08X", chksum));

生成此输出:

09-27 15:45:51.085 29517-29517/com.test.checksum.checksum I/Checksum: getting checksum for /data/app/com.test.checksum.checksum-2/base.apk
09-27 15:45:51.085 29517-29517/com.test.checksum.checksum I/Checksum: Size: 3245610
09-27 15:45:51.085 29517-29517/com.test.checksum.checksum I/Checksum: Date: Wed Sep 27 15:45:30 BST 2017
09-27 15:45:51.085 29517-29517/com.test.checksum.checksum I/Checksum: And now do something else!
09-27 15:45:52.335 29517-29517/com.test.checksum.checksum I/Checksum: Checksum is  0DAD53E0

File().list()

谢谢

2 回复 | 直到 7 年前

user1531971 user1531971 7 年前

cis.getChecksum().getValue()

您所做的是从一个新实例化的CRC32对象中获取相同的长值,该对象从未更改。

通常创建流:

CheckedInputStream cis = new CheckedInputStream(fis, new CRC32())

也就是说,传入的校验和不是“out”变量。一旦计算完成,您必须从流中获取它。

TheGribble 7 年前

但是,如果我用稍微不同的代码构建两个APK文件并手动安装,那么一切似乎都很好——安装每个APK文件都会给出一个单独的校验和,但每个文件的校验和是一致的。

我只能假设Android Studio调试器安装了一个标准或核心APK文件,并在调试器中运行时从其他地方加载代码,如Visual Studio。vshost。exe文件。

谢谢你抽出时间,

本。