0 
query = "SELECT * FROM POST_COMMENT WHERE Post_date_time= ? AND Post_User= !;";
     query = query.replace("?", "'"+post.getDatetime()+"'");
     query = query.replace("!", Integer.toString(post.getPublisher().getID()));

    PreparedStatement pstm = con.prepareStatement(query);
    ResultSet rs = pstm.executeQuery();

结果查询如下所示

SELECT * FROM POST_COMMENT WHERE Post_date_time= '2013-04-12 07:20:34.0' AND Post_User= 378;

在 MySQL 提示行中可以正常工作，但是从准备好的语句启动时会引发此错误：

Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '07:20:34.0 AND Post_User=378' at line 1

但

pstm.setString(1, post.getDatetime());
pstm.setString(2, Integer.toString(post.getPublisher().getID()));

也不工作。

表定义

CREATE TABLE Post_Comment (
  Comment_ID INTEGER(7) NOT NULL,
  Post_date_time DATETIME NOT NULL,
  Post_User INTEGER(7) NOT NULL,
  PRIMARY KEY(Comment_ID, Post_date_time, Post_User),
  CONSTRAINT Post_Comment_Post
    FOREIGN KEY (Post_User, Post_date_time)
    REFERENCES Post (User, date_time)
    ON DELETE   CASCADE
    ON UPDATE CASCADE,
  CONSTRAINT Post_Comment_Comment
    FOREIGN KEY (Comment_ID)
    REFERENCES Commentary (ID)
    ON DELETE   CASCADE
    ON UPDATE CASCADE
)
;

请帮忙。

4

2 回答 2

3 
query = "SELECT * FROM POST_COMMENT WHERE Post_date_time= ? AND Post_User= ?;";

PreparedStatement pstm = con.prepareStatement(query);
pstm.setObject(1, post.getDatetime());
pstm.setObject(2, post.getPublisher().getID());
ResultSet rs = pstm.executeQuery();
于 2013-04-14T04:11:35.643 回答
3

查看Java 教程。您不应该replace()使用 String 函数的字段。

您应该调用PreparedStatement 的“设置”方法。

编辑：

不，看看可用的方法。以及数据库列期望的类型。如果您想要日期，请使用setDate()，如果您想要整数，请使用setInt()。例子：

query = "SELECT * FROM POST_COMMENT WHERE Post_date_time = ? AND Post_User = ?;";

PreparedStatement pstm = con.prepareStatement(query);
pstm.setDate(1, post.getDatetime());
pstm.setInt(2, post.getPublisher().getID());
ResultSet rs = pstm.executeQuery();

另请注意，查询?用于两个占位符，而不是!.

于 2013-04-14T04:11:48.727 回答