Java DiskLruCache類代碼示例

import com.squareup.okhttp.internal.DiskLruCache; //導入依賴的package包/類
@Override public CacheResponse get(URI uri, String requestMethod,
    Map<String, List<String>> requestHeaders) {
  String key = uriToKey(uri);
  DiskLruCache.Snapshot snapshot;
  Entry entry;
  try {
    snapshot = cache.get(key);
    if (snapshot == null) {
      return null;
    }
    entry = new Entry(snapshot.getInputStream(ENTRY_METADATA));
  } catch (IOException e) {
    // Give up because the cache cannot be read.
    return null;
  }

  if (!entry.matches(uri, requestMethod, requestHeaders)) {
    snapshot.close();
    return null;
  }

  return entry.isHttps() ? new EntrySecureCacheResponse(entry, snapshot)
      : new EntryCacheResponse(entry, snapshot);
}
 

import com.squareup.okhttp.internal.DiskLruCache; //導入依賴的package包/類
private void update(CacheResponse conditionalCacheHit, HttpURLConnection httpConnection)
    throws IOException {
  HttpEngine httpEngine = getHttpEngine(httpConnection);
  URI uri = httpEngine.getUri();
  ResponseHeaders response = httpEngine.getResponseHeaders();
  RawHeaders varyHeaders =
      httpEngine.getRequestHeaders().getHeaders().getAll(response.getVaryFields());
  Entry entry = new Entry(uri, varyHeaders, httpConnection);
  DiskLruCache.Snapshot snapshot = (conditionalCacheHit instanceof EntryCacheResponse)
      ? ((EntryCacheResponse) conditionalCacheHit).snapshot
      : ((EntrySecureCacheResponse) conditionalCacheHit).snapshot;
  DiskLruCache.Editor editor = null;
  try {
    editor = snapshot.edit(); // returns null if snapshot is not current
    if (editor != null) {
      entry.writeTo(editor);
      editor.commit();
    }
  } catch (IOException e) {
    abortQuietly(editor);
  }
}
 

import com.squareup.okhttp.internal.DiskLruCache; //導入依賴的package包/類
public CacheRequestImpl(final DiskLruCache.Editor editor) throws IOException {
  this.editor = editor;
  this.cacheOut = editor.newOutputStream(ENTRY_BODY);
  this.body = new FilterOutputStream(cacheOut) {
    @Override public void close() throws IOException {
      synchronized (HttpResponseCache.this) {
        if (done) {
          return;
        }
        done = true;
        writeSuccessCount++;
      }
      super.close();
      editor.commit();
    }

    @Override public void write(byte[] buffer, int offset, int length) throws IOException {
      // Since we don't override "write(int oneByte)", we can write directly to "out"
      // and avoid the inefficient implementation from the FilterOutputStream.
      out.write(buffer, offset, length);
    }
  };
}
 

import com.squareup.okhttp.internal.DiskLruCache; //導入依賴的package包/類
public void writeTo(DiskLruCache.Editor editor) throws IOException {
  OutputStream out = editor.newOutputStream(ENTRY_METADATA);
  Writer writer = new BufferedWriter(new OutputStreamWriter(out, UTF_8));

  writer.write(uri + '\n');
  writer.write(requestMethod + '\n');
  writer.write(Integer.toString(varyHeaders.length()) + '\n');
  for (int i = 0; i < varyHeaders.length(); i++) {
    writer.write(varyHeaders.getFieldName(i) + ": " + varyHeaders.getValue(i) + '\n');
  }

  writer.write(responseHeaders.getStatusLine() + '\n');
  writer.write(Integer.toString(responseHeaders.length()) + '\n');
  for (int i = 0; i < responseHeaders.length(); i++) {
    writer.write(responseHeaders.getFieldName(i) + ": " + responseHeaders.getValue(i) + '\n');
  }

  if (isHttps()) {
    writer.write('\n');
    writer.write(cipherSuite + '\n');
    writeCertArray(writer, peerCertificates);
    writeCertArray(writer, localCertificates);
  }
  writer.close();
}
 

import com.squareup.okhttp.internal.DiskLruCache; //導入依賴的package包/類
private FilterInputStream getFromCache(String url) throws Exception {
    DiskLruCache cache = DiskLruCache.open(CommonUtil.getImageSavePath(), 1, 2, 2*1024*1024);
    cache.flush();
    String key = Util.hash(url);
    final DiskLruCache.Snapshot snapshot;
    try {
        snapshot = cache.get(key);
        if (snapshot == null) {
            return null;
        }
    } catch (IOException e) {
        return null;
    }
    FilterInputStream bodyIn = new FilterInputStream(snapshot.getInputStream(1)) {
        @Override
        public void close() throws IOException {
            snapshot.close();
            super.close();
        }
    };
    return bodyIn;
}
 

import com.squareup.okhttp.internal.DiskLruCache; //導入依賴的package包/類
private void update(CacheResponse conditionalCacheHit, HttpURLConnection httpConnection) throws IOException {
    HttpEngine httpEngine = getHttpEngine(httpConnection);
    URI uri = httpEngine.getUri();
    ResponseHeaders response = httpEngine.getResponseHeaders();
    RawHeaders varyHeaders = httpEngine.getRequestHeaders().getHeaders().getAll(response.getVaryFields());
    Entry entry = new Entry(uri, varyHeaders, httpConnection);
    DiskLruCache.Snapshot snapshot = (conditionalCacheHit instanceof EntryCacheResponse) ? ((EntryCacheResponse) conditionalCacheHit).snapshot : ((EntrySecureCacheResponse) conditionalCacheHit).snapshot;
    DiskLruCache.Editor editor = null;
    try {
        editor = snapshot.edit(); // returns null if snapshot is not current
        if (editor != null) {
            entry.writeTo(editor);
            editor.commit();
        }
    } catch (IOException e) {
        abortQuietly(editor);
    }
}