java - JDBC、MySQL : getting back row data from PreparedStatement executes

Question

我正在使用以下设置:

public MySQLProcessWriter(Connection con) throws SQLException { 
 String returnNames[] = {"processId","length","vertices"};
 addresser = con.prepareStatement("INSERT INTO addressbook (length, vertices, activity) VALUES (?, ?, ?)", returnNames);
}

processId 对应于地址簿表中的自动递增列。所以想法是:我有一个重复的插入，我取回一些插入的内容+自动生成的processId。但是，当我在执行准备好的语句(在适当设置值之后)后尝试 addresser.getGenerateKeys().getInt("processId"); 时，出现“未找到列”SQLException 。其代码是

addresser.setInt(1, length);
addresser.setInt(2, vertices);
addresser.setDouble(3, activity);
addresser.executeUpdate();
int processId = addresser.getGeneratedKeys().getInt("processId");

在更新长度、顶点、 Activity 的循环内。那么...什么给出了？我是否误解了prepareStatement(sqlstring, string[])方法的作用？

Answer 1

我认为你需要对返回的结果集调用 next()

ResultSet keys = addresser.getGeneratedKeys();
int processId = -1;
if (keys.next())
{
  processId = keys.getInt("processId");
}