java 设置查询参数；参数值与预期类型不匹配
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setQueryParams; Parameter value did not match expected type
提问by Hymanson Bray
Ok, so I have the user inputing a date, which is to be queried in java using em.createQuery. As you can see from the screenshots, I have the input data going in as pattern="dd-MMM-yy(thats how its stored in the server), but I have also tried this without the pattern tag and it still does not work. The actual error is at the setQueryParams(q)though and I haven't been able to figure out what it is. Anyone have an idea to where I might look? THanks.
好的，所以我让用户输入一个日期，该日期将在 java 中使用em.createQuery进行查询。正如您从屏幕截图中看到的那样，我将输入数据输入为pattern="dd-MMM-yy（这就是它存储在服务器中的方式），但是我也尝试过没有模式标记的情况，但它仍然无法正常工作. 实际的错误是在setQueryParams(q) 上，但我一直无法弄清楚它是什么。有人知道我可能在哪里看吗？谢谢。
回答by matt b
You haven't shown us what qis, but it sounds like you are giving a java.lang.Stringwhere a java.util.Dateis expected.
您还没有向我们展示什么q是，但听起来您给出了java.lang.String一个java.util.Date预期的地方。
Also, what is up with writing strings like
另外，写字符串是怎么回事
queryStr += " and c." + "dateCreated" + " >=:" + ...
? that looks like a pain to maintain/read.
? 这看起来很难维护/阅读。
回答by eric
I agree with Matt b, looks like you're supplying a string and expecting a date (though it's hard to read the text on your screenshot). Take a look at SimpleDateFormat, and use the "parse" method to derive a Date object from a String.
我同意 Matt b 的观点，看起来您正在提供一个字符串并期待一个日期（尽管很难阅读屏幕截图上的文字）。看看SimpleDateFormat，并使用“解析”方法从字符串派生一个 Date 对象。
Edit:
编辑：
It looks like you're date is in a string format that looks something like this:
看起来您的日期是字符串格式，如下所示：
Tue Jan 01 00:00:00 EST 2013
美国东部时间 2013 年 1 月 1 日星期二 00:00:00
Here is code that should parse a string in that format:
这是应该解析该格式字符串的代码：
public static void main(String[] args) {
String dateString = "Tue Jan 01 00:00:00 EST 2013";
SimpleDateFormat format = new SimpleDateFormat("EEE MMM dd hh:mm:ss z yyyy");
try {
Date date = format.parse(dateString);
System.out.println(date.toString());
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
I can't tell by looking at your log statements if the square brackets are part of your string or not, if they are you'd have to include those in your format:
我无法通过查看您的日志语句来判断方括号是否是字符串的一部分，如果是，您必须在格式中包含这些内容：
SimpleDateFormat format = new SimpleDateFormat("[EEE MMM dd hh:mm:ss z yyyy]");
Note I don't have your exactdate string here, so I may have made a mistake transcribing it from your image. Use a breakpoint or a print statement to get the exact format of the String q.
注意我这里没有您的确切日期字符串，所以我可能在从您的图像转录它时犯了一个错误。使用断点或打印语句来获取字符串 q 的确切格式。
Of course, this is all under the assumption that q is a string, based on your logs it seems like that's the case.
当然，这一切都假设 q 是一个字符串，根据您的日志，情况似乎就是这样。
