java - 如何修复 "This ResultSet is closed "错误？

Question

我想在我的 java 代码中使用两个 sql 查询。第一个查询保留 table2 的所有行，第二个查询逐行获取它的行。我写了下面的代码，但它面对“这个 ResultSet 已关闭，这意味着 rs ResultSet”错误。我该如何解决？

try{
 String sqlSelectTable2 = "SELECT * FROM table2;";
        ResultSet rs = stmt.executeQuery(sqlSelectTable2); 
while (rs.next()) {
            String strLineId = rs.getString(1);
           String strPoints = rs.getString(2);
        String sqlWithin = "SELECT ST_Within(ST_GeometryFromText('POINT( ),ST_GeomFromText('POLYGON((443425 4427680, 441353 4427680, 441368 4426075, 443762 4426149, 443425 4427680))', 4326));";
ResultSet rsWithin = stmt.executeQuery(sqlWithin);
} // end while ... **It get error when it is reading second ResultSet **
} catch (Exception e) {
System.out.println(e.getMessage());
}

Answer 1

您需要为内部查询创建单独的 PreparedStatement 对象

try{
 String sqlSelectTable2 = "SELECT * FROM table2;";
 ResultSet rs = stmt.executeQuery(sqlSelectTable2); 
 while (rs.next()) {
       String strLineId = rs.getString(1);
       String strPoints = rs.getString(2);
       PreparedStatement preparedStatement = null;
       String sqlWithin = "SELECT ST_Within(ST_GeometryFromText('POINT( ),ST_GeomFromText('POLYGON((443425 4427680, 441353 4427680, 441368 4426075, 443762 4426149, 443425 4427680))', 4326));";

       preparedStatement = dbConnection.prepareStatement(sqlWithin);
       ResultSet rsWithin = preparedStatement.executeQuery();
} // end while ... **It get error when it is reading second ResultSet **
} catch (Exception e) {
System.out.println(e.getMessage());
}