在postgresql中,当它是“没有时区的时间戳”时,Java中的参数类型

postgresql中“table”的“activitydate”列是“没有时区的时间戳”.我试图使用String来传递日期但是没有用(org.postgresql.util.PSQLException：错误：运算符不存在：没有时区的时间戳>字符变化).

我应该使用什么类型而不是String来存储“start_date”和“end_date”并将它们传递给查询？

BTW SELECT COUNT(*)FROM表WHERE activitydate> ‘2014-11-20’AND activitydate< '2014-11-21'AND zipcode = 12345在pgadmin中完美运行.

public Response query(
          @QueryParam("start_date") String start_date,@QueryParam("end_date") String end_date,@QueryParam("zipcode") String zipcode
          ) throws Exception {
...
...

pstmt = conn.prepareStatement("SELECT COUNT(*) FROM table WHERE activitydate > ? AND activitydate < ? AND zipcode = ?");

pstmt.setString(1,start_date); 
pstmt.setString(2,end_date); 
pstmt.setString(3,zipcode);

更新：
我将其更改为java.sql.Timestamp但仍然无效：

public Response query(
          @QueryParam("start_date") Timestamp start_date,@QueryParam("end_date") Timestamp end_date,@QueryParam("zipcode") String zipcode
          ) throws Exception {
...
...

pstmt = conn.prepareStatement("SELECT COUNT(*) FROM table WHERE activitydate > ? AND activitydate < ? AND zipcode = ?");

pstmt.setTimestamp(1,start_date); 
pstmt.setTimestamp(2,zipcode);