Apache Ignite缓存未命中处理程序

1 回答

• 0

  通过这篇伟大的文章https://dzone.com/articles/apache-ignite-how-to-read-data-from-persistent-sto得到了答案 . 如果存在高速缓存未命中，我们可以通过高速缓存存储从db获取它，如下所示

  public class PersonStore implements CacheStore<Long, Person> {
  
  @SpringResource(resourceName = "dataSource")
  private DataSource dataSource;
  
  // This method is called whenever IgniteCache.loadCache() method is called.
  @Override
  public void loadCache(IgniteBiInClosure<Long, Person> clo, @Nullable Object... objects) throws CacheLoaderException {
      System.out.println(">> Loading cache from store...");
  
      try (Connection conn = dataSource.getConnection()) {
          try (PreparedStatement st = conn.prepareStatement("select * from PERSON")) {
              try (ResultSet rs = st.executeQuery()) {
                  while (rs.next()) {
                      Person person = new Person(rs.getLong(1), rs.getLong(2), rs.getString(3), rs.getInt(4));
  
                      clo.apply(person.getId(), person);
                  }
              }
          }
      }
      catch (SQLException e) {
          throw new CacheLoaderException("Failed to load values from cache store.", e);
      }
  }
  
  // This method is called whenever IgniteCache.get() method is called.
  @Override
  public Person load(Long key) throws CacheLoaderException {
      System.out.println(">> Loading person from store...");
  
      try (Connection conn = dataSource.getConnection()) {
          try (PreparedStatement st = conn.prepareStatement("select * from PERSON where id = ?")) {
              st.setString(1, key.toString());
  
              ResultSet rs = st.executeQuery();
  
              return rs.next() ? new Person(rs.getLong(1), rs.getLong(2), rs.getString(3), rs.getInt(4)) : null;
          }
      }
      catch (SQLException e) {
          throw new CacheLoaderException("Failed to load values from cache store.", e);
      }
  }
  
  // Other CacheStore method implementations.
  …
  

  }

  回复于 2024-05-13T07:17:17+08:00