传递Date参数以创建日期范围查询 [英] passing Date parameter to create date range query
问题描述
使用下面的代码我想问一下如何传递来自文本字段的日期参数。我打算使用DAO和servlet创建一个简单的日期范围查询。我可以使用此代码显示所有列但是我想使用日期过滤...
Using the codes below I would like to ask how can I pass a "Date" parameter coming from a text field. I am planning to create a simple date range query using DAO and servlet. I can display all columns using this codes however I want to filter in using Date...
这是我的代码:
My Servlet
package source;
import java.io.*;
import java.sql.SQLException;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.*;
/**
*
* @author jaypee.martinez
*/
public class parseServlet extends HttpServlet {
private parseDAO parseDAO;
@Override
public void init() throws ServletException {
String driver = "org.postgresql.Driver";
String url = "jdbc:postgresql://localhost5432/mydb";
String username = "postgres";
String password = "secret";
Database database = new Database(driver, url, username, password);
this.parseDAO = new parseDAO(database);
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
List<parseBean> parse_array = parseDAO.results();
request.setAttribute("parse_array", parse_array);
request.getRequestDispatcher("results.jsp").forward(request, response);
}
catch (SQLException e) {
throw new ServletException("Cannot retrieve areas", e);
}
}
}
和我的DAO
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package source;
import java.sql.*;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
public class parseDAO {
private Database database;
public parseDAO(Database database) {
this.database = database;
}
public List<parseBean> results() throws SQLException {
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
List<parseBean> parse_array = new ArrayList<parseBean>();
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
try {
connection = database.getConnection();
statement = connection.prepareStatement("select * from dateparse");
resultSet = statement.executeQuery();
while (resultSet.next()) {
parseBean parsearray = new parseBean();
parsearray.setDate(resultSet.getDate("date"));
parsearray.setName(resultSet.getString("name"));
parsearray.setAddress(resultSet.getString("address"));
parse_array.add(parsearray);
}
} finally {
if (resultSet != null) try { resultSet.close(); } catch (SQLException logOrIgnore) {}
if (statement != null) try { statement.close(); } catch (SQLException logOrIgnore) {}
if (connection != null) try { connection.close(); } catch (SQLException logOrIgnore) {}
}
return parse_array;
}
}
推荐答案
使用 HttpServletRequest#getParameter()
收集请求参数。假设输入字段的名称为 date
。
String dateString = request.getParameter("date");
使用 SimpleDateFormat #parse()
to将其转换为 java.util。使用特定模式的日期
,具体取决于要求最终用户输入日期的方式。
Use SimpleDateFormat#parse()
to convert it to java.util.Date
using a specific pattern, depending on how the enduser was asked to enter the date.
Date date = null;
try {
date = new SimpleDateFormat("yyyy-MM-dd").parse(dateString);
}
catch (ParseException e) {
// Show error message to enduser about the wrong format and forward back to the JSP with the form.
request.setAttribute("error", "Invalid format, please enter yyyy-MM-dd");
request.getRequestDispatcher("search.jsp").forward(request, response);
return;
}
将此作为方法参数传递给DAO方法:
Pass this as a method argument to your DAO method:
List<ParseBean> results = parseDAO.search(date);
您需要将其转换为 java.sql.Date
,以便您可以使用 PreparedStatement #setDate()
在SQL查询上设置它:
You need to convert it to java.sql.Date
, so that you can use PreparedStatement#setDate()
to set it on the SQL query:
String query = "SELECT * FROM dateparse WHERE date = ?";
// ...
statement.setDate(1, new java.sql.Date(date.getTime()));
您可以使用 WHERE日期> ?
搜索比给定日期更新的记录,或 WHERE date< ?
搜索超过给定日期的记录,或 WHERE日期BETWEEN?和?
搜索指定日期之间的记录。
You can use WHERE date > ?
to search for records newer than the given date, or WHERE date < ?
to search for records older than the given date, or WHERE date BETWEEN ? and ?
to search for records between the specified dates.
这篇关于传递Date参数以创建日期范围查询的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!