写一个java方法从apk中找到APK签名分块参数是RandomAccessFile apk long centralDirOffset 返回值是PairByteBuffer Long

以下是一个可以实现你要求的Java方法：

import javafx.util.Pair;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;

public class ApkSignatureBlockFinder {
    public static Pair<ByteBuffer, Long> findSignatureBlock(RandomAccessFile apk, long centralDirOffset) throws IOException {
        // 移动到中央目录的偏移量位置
        apk.seek(centralDirOffset);

        // 搜索APK签名分块的魔数
        byte[] magicBytes = {'P', 'K', 0x05, 0x06};
        byte[] buffer = new byte[4];
        long signatureBlockOffset = -1;
        while (apk.read(buffer) != -1) {
            if (buffer[0] == magicBytes[0] &&
                    buffer[1] == magicBytes[1] &&
                    buffer[2] == magicBytes[2] &&
                    buffer[3] == magicBytes[3]) {
                signatureBlockOffset = apk.getFilePointer() - 4;
                break;
            }

            apk.seek(apk.getFilePointer() - 3);
        }

        if (signatureBlockOffset == -1) {
            throw new IOException("APK signature block not found.");
        }

        // 获取APK签名分块的大小
        apk.seek(signatureBlockOffset + 12);
        int signatureBlockSize = apk.readInt();

        // 读取APK签名分块的内容
        apk.seek(signatureBlockOffset);
        ByteBuffer signatureBlockBuffer = ByteBuffer.allocate(signatureBlockSize);
        apk.readFully(signatureBlockBuffer.array());

        return new Pair<>(signatureBlockBuffer, signatureBlockOffset);
    }

    public static void main(String[] args) {
        try {
            RandomAccessFile apkFile = new RandomAccessFile("path/to/your/apk", "r");
            long centralDirOffset = 12345; // 设置中央目录的偏移量
            Pair<ByteBuffer, Long> result = findSignatureBlock(apkFile, centralDirOffset);
            ByteBuffer signatureBlock = result.getKey();
            long signatureBlockOffset = result.getValue();

            // 打印APK签名分块的内容和偏移量
            System.out.println("Signature Block Offset: " + signatureBlockOffset);
            System.out.println("Signature Block Content: " + new String(signatureBlock.array()));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请注意，你需要将 path/to/your/apk 替换为你实际的APK文件路径，以及设置正确的中央目录的偏移量。此方法将搜索APK文件中的APK签名分块，并返回一个 Pair 对象，其中包含签名分块的内容（作为 ByteBuffer 对象）和签名分块的偏移量。在 main 方法中，你可以根据需要处理这些返回值