java - 如何获取preparedstatement中的batch数？

Question

我想这一定很简单。为此必须有一些方法。这就是我想要的:-

PreparedStatement ps = ...
ps.addBatch ( );
ps.addBatch ( );
ps.addBatch ( );
logger.info ( "totalBatches: " + ps.someMethod() ); 
ps.executeBatch ( );

结果将是:总批处理:3；
如果没有这样的方法，那怎么办呢？

Answer 1

不支持此功能。但是您可以通过添加计数成员来包装 Statement 并覆盖 addBatch() 。如果使用 Apache Commons DBCP ，您可以从 DelegatingPreparedStatement 继承，否则您缺少 PreparedStatement 的包装器。所以我使用代理添加方法:

public class BatchCountingStatementHandler implements InvocationHandler {

  public static BatchCountingStatement countBatches(PreparedStatement delegate) {
    return Proxy.newProxyInstance(delegate.getClassLoader(), new Class[] {BatchCountingStatement.class}, new BatchCountingStatementHandler(delegate));
  }

  private final PreparedStatement delegate;
  private int count = 0;

  private BatchCountingStatementHandler(PreparedStatement delegate) {
    this.delegate = delegate;
  }

  public Object invoke(Object proxy, Method method, Object[] args)
    throws Throwable {
    if ("getBatchCount".equals(method.getName())) {
      return count;
    }
    try {
      return method.invoke(delegate, args);
    } finally {
      if ("addBatch".equals(method.getName())) {
        ++count;
      }
    }
  }

  public static interface BatchCountingStatement extends PreparedStatement {
    public int getBatchCount();
  }
}