java - 为什么 While (rs.next()) 语句在第一次迭代后结束？

Question

我正在使用 SELECT 语句从表中获取数据，然后将其插入到另一个表中。然而，“stmt.executeQuery(query);”这一行从表中插入第一行然后退出。当我注释掉这一行时，while 循环遍历所有打印出来的行。堆栈跟踪没有显示任何错误。为什么会这样？

try{                
    String query = "SELECT * FROM "+schema_name+"."+table;

    rs = stmt.executeQuery(query);

    while (rs.next()) {

        String bundle = rs.getString("BUNDLE");
        String project_cd = rs.getString("PROJECT_CD");
        String dropper = rs.getString("DROPPER");
        String week = rs.getString("WEEK");
        String drop_dt = rs.getString("DROP_DT").replace(" 00:00:00.0","");

        query = "INSERT INTO INDUCTION_INFO (BUNDLE, PROJECT_CD, DROPPER, WEEK, DROP_DT) "
              + "VALUES ("
              + bundle+","
              + "'"+project_cd+"',"
              + dropper+","
              + week+","
              + "to_date('"+drop_dt+"','YYYY-MM-DD'))";

        System.out.println(query);

        stmt.executeQuery(query);
    }
}catch(Exception e){
    e.printStackTrace();
}

Answer 1

您正在重新使用用于在循环的最后一行生成 rs 的 Statement。

这将关闭 ResultSet rs。作为stated in the documentation :

A ResultSet object is automatically closed when the Statement object that generated it is closed, re-executed, or used to retrieve the next result from a sequence of multiple results.

您需要使用第二个 Statement 对象来执行 INSERT 语句。