java.util.Date cannot be cast to java.sql.Date 将date类型的数据存入数据库

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页面接受的date是java.util.date，放入数据库要用java.sql.date，实现两者之间的转化：

1.user.java
package model;

import java.util.Date;

public class User {
public String username,password,address,email;
Date birth;
public User(){

}
public User(String username, String password, String address, String email, Date birth) {
super();
this.username = username;
this.password = password;
this.address = address;
this.email = email;
this.birth = birth;
}
//getter,setter方法。。略

}

2.add.jsp：注册页面（我写的是struts2项目，但是将date放入数据库的例子是常见的）

<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<%@taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>注册</title>
</head>
<body>
<s:form action="add" methods="post">
<s:fielderror/>
<table width="60%" height="76" border="0">
<s:textfield name="user.username" label="用户名"/>
<s:password name="user.password" label="密码"/>
<s:textfield name="user.email" label="邮箱"/>
<s:textfield name="user.address" label="地址"/>
<s:textfield name="user.birth" format="yyyy-MM-dd" nice="false" label="出生日期"/>

<s:submit value="注册" align="center"/>
</table>
</s:form>
</body>
</html>

3.AddAction.java

package com;
import com.opensymphony.xwork2.ActionSupport;
import java.util.*;
import dao.AddDao;
import model.User;

public class AddAction extends ActionSupport{
private static String FORWARD=null;//页面导向
private User user =new User();
//private User user;
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public String execute() throws Exception{
AddDao dao=new AddDao();
User u=new User();
u=dao.findName(this.user.getUsername());

if(u.getUsername()==null){
System.out.println("注册成功");
// System.out.println(this.user.getUsername());
// System.out.println(u.getUsername());
// System.out.println(u.getBirth());
dao.add(this.user);//在AddDao中
FORWARD="success";
}
else{
System.out.println("注册失败");
FORWARD="input";
}

return FORWARD;
}
}

4.AddDao.java

package dao;

import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import model.User;

public class AddDao {
Connection con;
String driver="com.mysql.jdbc.Driver";
String url="jdbc:mysql://localhost:3306/struts2";
public AddDao(){
try{
Class.forName(driver);
this.con=DriverManager.getConnection(url,"root","root");
}catch(Exception e){
e.printStackTrace();
}
}
/*

public void add(User user){
String sql="INSERT INTO user(username,password,address,email,birth) VALUES ( ?, ?, ?, ? ,?)";
try {
PreparedStatement cmd=this.con.prepareStatement(sql);
cmd.setString(1, user.getUsername());
cmd.setString(2, user.getPassword());
cmd.setString(3, user.getAddress());
cmd.setString(4, user.getEmail());
cmd.setDate(5, new java.sql.Date(user.getBirth().getTime()));//重点
cmd.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

...
}

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