perf: 优化快照接口——缓存预序列化 JSON,消除重复序列化

- Caffeine 缓存改为存储 bundle JSON 字符串而非 SiteSnapshot 对象(减少内存占用)
- 新增 getActiveBundleJson 方法,SnapshotController 直接使用缓存 JSON
- bundle JSON 新增 checksum 字段,ETag 比较无需额外查库
- 删除 SnapshotController.toJson 重复序列化代码
- publish 时复用已序列化的 JSON 上传 CDN
This commit is contained in:
mediabot-pt
2026-07-07 11:28:28 +08:00
parent 9f94b53753
commit 820b180d87
3 changed files with 42 additions and 49 deletions

View File

@@ -34,6 +34,13 @@ public interface SiteSnapshotService {
*/
SiteSnapshot getActive(String siteId);
/**
* 获取站点当前生效快照的预序列化 JSON(带 Caffeine 缓存)
* 供 SnapshotController 使用,避免重复序列化
* @return JSON 字符串,或 null 表示无快照
*/
String getActiveBundleJson(String siteId);
/**
* 按 checksum 判断是否需要更新
*/

View File

@@ -43,8 +43,8 @@ public class SiteSnapshotServiceImpl implements SiteSnapshotService {
private final CachedStorageService storageService;
private static final ObjectMapper om = new ObjectMapper();
/** 已发布快照本地缓存:key=siteId, value=SiteSnapshot */
private final Cache<String, SiteSnapshot> activeSnapshotCache = Caffeine.newBuilder()
/** 已发布快照 JSON 缓存:key=siteId, value=预序列化的 bundle JSON */
private final Cache<String, String> bundleJsonCache = Caffeine.newBuilder()
.expireAfterWrite(Duration.ofMinutes(10))
.maximumSize(500)
.build();
@@ -193,12 +193,12 @@ public class SiteSnapshotServiceImpl implements SiteSnapshotService {
draft.setPublishedAt(LocalDateTime.now());
snapshotMapper.updateById(draft);
// 刷新本地缓存
activeSnapshotCache.put(siteId, draft);
// 序列化并刷新缓存
String bundleJson = toBundleJson(draft);
bundleJsonCache.put(siteId, bundleJson);
// 上传到七牛云 CDN 作为灾备
// 上传到七牛云 CDN 作为灾备(复用已序列化的 JSON)
try {
String bundleJson = toBundleJson(draft);
String cdnPath = "snapshots/" + siteId + ".json";
storageService.store(cdnPath, bundleJson);
// 也保存版本化副本
@@ -217,9 +217,19 @@ public class SiteSnapshotServiceImpl implements SiteSnapshotService {
@Override
public SiteSnapshot getActive(String siteId) {
return activeSnapshotCache.get(siteId, key -> {
log.debug("缓存未命中,查询数据库 siteId={}", siteId);
return snapshotMapper.selectLatestPublished(siteId);
return snapshotMapper.selectLatestPublished(siteId);
}
@Override
public String getActiveBundleJson(String siteId) {
return bundleJsonCache.get(siteId, key -> {
SiteSnapshot active = snapshotMapper.selectLatestPublished(key);
if (active == null) {
log.debug("站点 {} 无 published 快照", key);
return ""; // 空字符串表示无数据,Caffeine 会缓存
}
log.debug("缓存未命中,序列化 siteId={}", key);
return toBundleJson(active);
});
}
@@ -253,6 +263,7 @@ public class SiteSnapshotServiceImpl implements SiteSnapshotService {
try {
Map<String, Object> bundle = new LinkedHashMap<>();
bundle.put("siteId", snapshot.getSiteId());
bundle.put("checksum", snapshot.getChecksum());
bundle.put("generatedAt", snapshot.getPublishedAt() != null
? snapshot.getPublishedAt().toString() : LocalDateTime.now().toString());