使用 JDBC 插入 PostgreSQL 时间类型时出错

Question

我在 postgres 数据库中有一个具有“没有时区的时间”数据类型的表，在尝试使用准备好的语句插入时出现语法错误。我尝试创建一个新的 java.sql.Time 对象，而不是使用来自网页的输入，但我仍然遇到同样的错误。我做错了什么？

错误：

org.postgresql.util.PSQLException: ERROR: invalid input syntax for type time: "1970-01-01 +01:00:00"

表：

                                     Table "public.reservation"
   Column   |          Type          |                          Modifiers
------------+------------------------+--------------------------------------------------------------
 res_id     | integer                | not null default nextval('reservation_res_id_seq'::regclass)
 cust_id    | character varying(50)  | not null
 date       | date                   | not null
 time       | time without time zone | not null
 num_people | integer                | not null
Indexes:
    "reservation_pkey" PRIMARY KEY, btree (res_id)
Foreign-key constraints:
    "reservation_cust_id_fkey" FOREIGN KEY (cust_id) REFERENCES customer(cust_id)
Referenced by:
    TABLE "reservation_table" CONSTRAINT "reservation_table_res_id_fkey" FOREIGN KEY (res_id) REFERENCES reservation(res_id)

预订Java：

 public static boolean createReservation(String custID, Date date, Time time, int numPeople) throws ServletException {

    //TODO add checking
    //TODO need to add determing table and if reservation time is free

    boolean succeeded = false;

    //checks if reservation is possible to be booked
    if(checkReservationPossible()){

        //convet date to correct format for database
        //SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy/MM/dd");
        //String formattedDate = dateFormatter.format(date);

        //convert time to correct format for database
        //SimpleDateFormat timeFormatter = new SimpleDateFormat("HH:mm");
        //String formattedTime = timeFormatter.format(time);

        DatabaseAccess db = new DatabaseAccess();
        String sql = "INSERT INTO reservation (cust_id, date, time, num_people)"
                + "VALUES (?,?,?,?)";

        LinkedList<Object> params = new LinkedList<Object>();
        params.add(custID);
        params.add(date);
        params.add(time);
        params.add(numPeople);

        succeeded = db.runUpdateQuery(sql,params);

        db.close();
    }

    return succeeded;
}

数据库访问 Java：

public boolean runUpdateQuery(String sql, LinkedList<Object> params) throws ServletException
{
    // Using try {...} catch {...} for error control
    try{
        // Create a statement variable to be used for the sql query
        //Statement statement = this.connection.createStatement();

        // Perform the update

        PreparedStatement pst = this.connection.prepareStatement(sql);

        Iterator iter = params.iterator();

        for(int i = 1;iter.hasNext(); i++){
            Object curr = iter.next();
            //TODO may need to add more for different types
            if(curr instanceof String){
                pst.setString(i, curr.toString());
            }else if (curr instanceof Integer){
                pst.setInt(i, (Integer)curr);
            }else if (curr instanceof java.util.Date){
                //convert to sql date
                java.util.Date tempDate = (java.util.Date)curr;
                java.sql.Date sqlDate = new java.sql.Date(tempDate.getTime());
                pst.setDate(i, sqlDate);
            }else if (curr instanceof Time){
                pst.setTime(i, Time.valueOf("11:30:00"));
            }
        }

        int numRows = pst.executeUpdate();

        pst.close();

        if(numRows > 0){
            return true;
        }else{
            return false;
        }
    } catch (SQLException e){
        // Deal with the error if it happens
        throw new ServletException(String.format("Error: Problem running query... "), e);
    }
}

Answer 1

您不需要所有这些检查。我建议您将代码更改为：

for (int i = 1; iter.hasNext(); i++) {
    Object curr = iter.next();    
    pst.setObject(i, curr);
}

JDBC 知道如何处理所有各种常用的 java 类型 - 无需转换。

您需要检查类型的唯一时间是如果您想使用一些自定义类并且想从中获取一些符合 JDBC 的类型。这不是这里的情况。

Answer 2

我认为问题在于 java 正在发送日期和时间，而不仅仅是时间。解决此问题的一个好方法是创建一个派生自 Time 的类并覆盖 toString() 方法，JDBC 内部使用该方法将 ? 替换为参数值：

public class PosgreSqlTime inherits java.sql.Time
{
     private static SimpleDateFormat SDF = new SimpleDateFormat("HH:mm:ss:SSS");
     @Override
     public String toString()
     {
          return SDF.format(this);
     }
}