String sql = "select count(*) from message";
ps =  cn.prepareStatement(sql);

rs = ps.executeQuery();
int rowCount = 0;
while(rs.next()) {
    rowCount = Integer.parseInt(rs.getString("count(*)"));
    System.out.println(Integer.parseInt(rs.getString("count(*)")));
}
System.out.println("Count : " + rowCount);

int i = 0;
while(rs.next()) {
    i++;
}

我检查了ResultSet接口的运行时值，发现它几乎一直都是一个ResultSetImpl。ResultSetImpl有一个名为getUpdateCount()的方法，它返回您正在寻找的值。

下面的代码示例应该足够了: ResultSet ResultSet = executeQuery(sqlQuery); double rowCount = ((ResultSetImpl)resultSet).getUpdateCount()

我知道向下转换通常是一个不安全的过程，但这个方法还没有让我失败。

为列命名。

String query = "SELECT COUNT(*) as count FROM

引用该列从ResultSet对象到int，并从那里做你的逻辑。

PreparedStatement statement = connection.prepareStatement(query);
statement.setString(1, item.getProductId());
ResultSet resultSet = statement.executeQuery();
while (resultSet.next()) {
    int count = resultSet.getInt("count");
    if (count >= 1) {
        System.out.println("Product ID already exists.");
    } else {
        System.out.println("New Product ID.");
    }
}

今天，我用了这个逻辑，为什么我不知道得到RS的计数。

int chkSize = 0;
if (rs.next()) {
    do {  ..... blah blah
        enter code here for each rs.
        chkSize++;
    } while (rs.next());
} else {
    enter code here for rs size = 0 
}
// good luck to u.

这是一种简单的行计数方法。

ResultSet rs = job.getSearchedResult(stmt);
int rsCount = 0;

//but notice that you'll only get correct ResultSet size after end of the while loop
while(rs.next())
{
    //do your other per row stuff 
    rsCount = rsCount + 1;
}//end while