类型不匹配：无法从 java.util.Date 转换为 java.sql.Date
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Type mismatch: cannot convert from java.util.Date to java.sql.Date
提问by Julie24
I am trying to get my code to work with the SimpleDateFormat class here in the code. Does anybody knows why? Have a nice day from Julie
我试图让我的代码与代码中的 SimpleDateFormat 类一起使用。有人知道为什么吗？祝朱莉度过愉快的一天
When I run the code where I have imported: import java.util.Date. I get the error: "The type Date is ambiguous" in the lines:
当我运行导入的代码时：import java.util.Date。我在行中收到错误：“日期类型不明确”：
Date startDate = format.parse(req.getParameter("startDate"));
Date endDate = format.parse(req.getParameter("endDate"));
When I run the code where I have imported: import java.sql.Date; I get the error:
当我运行导入的代码时： import java.sql.Date; 我收到错误：
Date startDate = format.parse(req.getParameter("startDate"));
Date endDate = format.parse(req.getParameter("endDate"));
"Type mismatch: cannot convert from java.util.Date to java.sql.Date"
“类型不匹配：无法从 java.util.Date 转换为 java.sql.Date”
import java.sql.Date;
package WorkPackage;
import java.io.*;
import java.sql.*;
import java.text.SimpleDateFormat;
import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.util.*;
import java.util.Date.*;
public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException{
String connectionURL = "jdbc:mysql://localhost/NekiWork";
Connection connection=null;
//String startDate = req.getParameter("startDate");
//String endDate= req.getParameter("endDate");
try {
//Load database driver
Class.forName("com.mysql.jdbc.Driver");
//Connection to the database
connection = DriverManager.getConnection(connectionURL, "root", "");
//Getting the data from database
String sql = "SELECT *, (Day_hours + (Day_minutes / 60)) AS Allday_hours FROM Workdata "
+ "WHERE Date = startdate = ? AND endDate = ? ";
PreparedStatement pst = connection.prepareStatement(sql);
//Date startDate;
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
Date startDate = format.parse(req.getParameter("startDate"));
Date endDate = format.parse(req.getParameter("endDate"));
pst.setDate(1,startDate);
pst.setDate(2, endDate);
采纳答案by Ravinder Reddy
java.util.Dateand java.sql.Dateare different. Database accepts only java.sql.Date.
For that, you need to convert java.util.Dateinto java.sql.Date.
java.util.Date并且java.sql.Date是不同的。数据库只接受java.sql.Date.
为此，您需要转换java.util.Date为java.sql.Date.
Try this:
尝试这个：
java.util.Date util_StartDate = format.parse( req.getParameter("startDate") );
java.sql.Date sql_StartDate = new java.sql.Date( util_StartDate.getTime() );
Now you can use this sql_StartDateto set parameter values using prepared statement.
现在您可以使用它sql_StartDate来使用准备好的语句设置参数值。
pst.setDate( 1, sql_StartDate );
Use the same procedure on other sql specific dates to use with jdbc.
在其他 sql 特定日期上使用相同的过程以与 jdbc 一起使用。
回答by Rich O'Kelly
Where you have both the java.sql.*and java.util.*namespaces imported, the compiler cannot uniquely determine a best type for the Datetoken. In this instance you can qualify your type with the namespace:
如果您同时导入了java.sql.*和java.util.*命名空间，编译器就无法唯一确定Date令牌的最佳类型。在这种情况下，您可以使用命名空间限定您的类型：
java.util.Date startDate = format.parse(req.getParameter("startDate"));
回答by Edwin Rafael Pimienta Calderon
Date fechaNace= new java.sql.Date(persona.getFechaNacimiento().getTime());
ps.setDate(6,(java.sql.Date) fechaNace);
