resource-platform/backend/repack_v3.py

import zipfile, os

SRC = "target/resource-platform-v2.jar"
DST = "target/resource-platform-v3.jar"
NEW_CLASS_SRC = "build_tmp_classes/com/example/resourceplatform/common/PurchaseDuration.class"
TARGET_ENTRY = "BOOT-INF/classes/com/example/resourceplatform/common/PurchaseDuration.class"

with open(NEW_CLASS_SRC, "rb") as f:
    new_bytes = f.read()

with zipfile.ZipFile(SRC, "r") as zin:
    infos = zin.infolist()
    manifest = zin.getinfo("META-INF/MANIFEST.MF")
    with zipfile.ZipFile(DST, "w", compression=zipfile.ZIP_DEFLATED) as zout:
        zout.writestr(manifest, zin.read(manifest.filename))
        for info in infos:
            name = info.filename
            if name == "META-INF/MANIFEST.MF":
                continue
            if name == TARGET_ENTRY:
                zi = zipfile.ZipInfo(name)
                zi.compress_type = info.compress_type
                zi.external_attr = info.external_attr
                zi.date_time = info.date_time
                zout.writestr(zi, new_bytes)
                print("replaced:", name)
            else:
                data = zin.read(info.filename)
                zi = zipfile.ZipInfo(name, date_time=info.date_time)
                zi.compress_type = info.compress_type
                zi.external_attr = info.external_attr
                zout.writestr(zi, data)
    print("wrote", DST, os.path.getsize(DST), "bytes")

# sanity: manifest first + class present
with zipfile.ZipFile(DST) as z:
    names = z.namelist()
    print("manifest first?", names[0] == "META-INF/MANIFEST.MF")
    print("class present?", TARGET_ENTRY in names)