【发布时间】：2019-07-23 11:46:06
【问题描述】：
我需要学习如何创建我的自定义 .tostring 和 .fromstring
我已尝试将其投射回对象，但它似乎不起作用 我也尝试检索对象并将其转换为字符串，然后比较字符串，但它仍然不起作用
问题从这里开始，所以 .toString() 试图绕过问题
我只能保存元素 id，但是在同时处理三个不同的表时检索时会很忙
我想要一个持久化来保存我可以通过它实现的所有对象，但在检索期间必须创建三个查询，这与我目前对事件实体所做的不同
detached entity passed to persist: entities.Event
package entities;
// Generated Jul 23, 2019 11:11:55 AM by Hibernate Tools 4.3.1
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
/**
* Event generated by hbm2java
*/
public class Event implements java.io.Serializable {
private Integer id;
private String image;
private String location;
private int upto100;
private Integer upto300;
private Integer upto500;
private Integer upto1000;
private int phoneno;
private String scenario;
private String name;
private String mail;
private Users owner;
private String description;
public Event() {
}
public Event(String image, String location, int upto100, int phoneno, String scenario, String name, String mail) {
this.image = image;
this.location = location;
this.upto100 = upto100;
this.phoneno = phoneno;
this.scenario = scenario;
this.name = name;
this.mail = mail;
}
public Event(String image, String location, int upto100, Integer upto300, Integer upto500, Integer upto1000, int phoneno, String scenario, String name, String mail, Users owner, String description) {
this.image = image;
this.location = location;
this.upto100 = upto100;
this.upto300 = upto300;
this.upto500 = upto500;
this.upto1000 = upto1000;
this.phoneno = phoneno;
this.scenario = scenario;
this.name = name;
this.mail = mail;
this.owner = owner;
this.description = description;
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getImage() {
return this.image;
}
public void setImage(String image) {
this.image = image;
}
public String getLocation() {
return this.location;
}
public void setLocation(String location) {
this.location = location;
}
public int getUpto100() {
return this.upto100;
}
public void setUpto100(int upto100) {
this.upto100 = upto100;
}
public Integer getUpto300() {
return this.upto300;
}
public void setUpto300(Integer upto300) {
this.upto300 = upto300;
}
public Integer getUpto500() {
return this.upto500;
}
public void setUpto500(Integer upto500) {
this.upto500 = upto500;
}
public Integer getUpto1000() {
return this.upto1000;
}
public void setUpto1000(Integer upto1000) {
this.upto1000 = upto1000;
}
public int getPhoneno() {
return this.phoneno;
}
public void setPhoneno(int phoneno) {
this.phoneno = phoneno;
}
public String getScenario() {
return this.scenario;
}
public void setScenario(String scenario) {
this.scenario = scenario;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String getMail() {
return this.mail;
}
public void setMail(String mail) {
this.mail = mail;
}
public Users getOwner() {
return this.owner;
}
public void setOwner(Users owner) {
this.owner = owner;
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
/*public String toStreng(Event event) throws JsonProcessingException {
return new ObjectMapper().writeValueAsString(event);
}
public Event fromStreng(String string) throws IOException {
return new ObjectMapper().readValue(string, Event.class);
}*/
}
这是我需要覆盖 .tostring 和 .fromstring 的类 下面的页面是我必须将对象转换为字符串的地方
<%--
Document : Book
Created on : Jul 21, 2019, 8:27:27 PM
Author : Tariana
--%>
<%@page import="java.util.Iterator"%>
<%@page import="java.util.List"%>
<%@page import="org.hibernate.service.ServiceRegistry"%>
<%@page import="org.hibernate.cfg.Configuration"%>
<%@page import="org.hibernate.service.ServiceRegistryBuilder"%>
<%@page import="org.hibernate.Session"%>
<%@page import="org.hibernate.Query"%>
<%@page import="org.hibernate.SessionFactory"%>
<%@page import="entities.*"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<%
String eventid = (String) session.getAttribute("venueid");
Users owner = new Users();
int id = Integer.parseInt(eventid);
SessionFactory sessionFactory;
ServiceRegistry serviceRegistry;
Configuration configuration = new Configuration();
configuration.addAnnotatedClass(Users.class)
.configure();
serviceRegistry = new ServiceRegistryBuilder()
.applySettings(configuration.getProperties())
.configure("hibernate.cfg.xml")
.build();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
Session sess = sessionFactory.openSession();
String hql = "SELECT e FROM Event e WHERE e.id = :id";
Query query = sess.createQuery(hql);
query.setInteger("id", id);
List<Event> products;
List results = query.list();
products = results;
Users own = null;
Event venues = null;
String upto;
Iterator<Event> itr = products.iterator();
while(itr.hasNext()){
Event g = itr.next();
System.out.println(g.getUpto100());
owner = g.getOwner();
own = owner;
venues = g;
}
System.out.println(own.getUsername());
String owns = (String) own.getUsername();
sess.close();
if(venues.getUpto300() != null){
upto = "upto300";
}else if(venues.getUpto500() != null){
upto = "upto500";
}else if(venues.getUpto1000() != null){
upto = "upto1000";
}else{
upto = "upto100";
}
session.setAttribute("owner", owner);
session.setAttribute("venue", venues);
%>
<html>
<head>
<style>
.navy{
float: right;
}
</style>
<%@include file = "BookHeader.jsp" %>
<title>Book</title>
</head>
<body>
<div id="lookbookHeader">
<video autoplay poster="data:image/png;base64, <%=venues.getImage()%>" onerror="this.onerror=null;this.poster='event.png';" id="bgvid">
</video>
<div id="headerContentContainer">
<h1 class="whitey"><%=venues.getName()%></h1>
<div class="initial-arrow-small"></div>
</div>
</div>
</div>
<div id="introContent">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/momentjs/2.14.1/moment.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.37/js/bootstrap-datetimepicker.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datetimepicker/4.17.37/css/bootstrap-datetimepicker.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<br>
<h2>Book Venue</h2>
<h5 class="lefty">Email:</h5> <h5 class="rightey"><%=venues.getMail()%></h5><br><br>
<h5 class="lefty">Max Capacity:</h5> <h5 class="rightey"><%=upto%></h5><br><br>
<h5 class="lefty">Price for up to 100 people:</h5> <h5 class="rightey"><%=venues.getUpto100()%></h5><br><br>
<h5 class="lefty">Price for up to 300 people:</h5> <h5 class="rightey"><%=venues.getUpto300()%></h5><br><br>
<h5 class="lefty">Price for up to 500 people:</h5> <h5 class="rightey"><%=venues.getUpto500() %></h5><br><br>
<h5 class="lefty">Price for up to 1000 people:</h5> <h5 class="rightey"><%=venues.getUpto1000()%></h5><br><br>
<h5 class="lefty">Phone no.:</h5> <h5 class="rightey"><%=venues.getPhoneno()%></h5><br><br>
<h5 class="lefty">Location:</h5> <h5 class="rightey"><%=venues.getLocation()%></h5><br><br>
<h5 class="lefty">Scenario:</h5> <h5 class="rightey"><%=venues.getScenario()%></h5><br><br>
<h5 class="lefty">Posted By:</h5> <h5 class="rightey"><%=owns%></h5><br><br>
<p class="lefty">Description:</p> <p class="rightey">
<%=venues.getDescription()%>
</p><br><br>
<h4>Set Event Details</h4>
<form action="/Eventer/Booking">
<!--<script src="//code.jquery.com/jquery-1.10.2.js"></script>
<script src="//code.jquery.com/ui/1.11.1/jquery-ui.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.11.1/themes/smoothness/jquery-ui.css"/>
<script>
$( "#from" ).datepicker().datepicker("setDate", "today");
$(function() {
$( "#from" ).datepicker({
defaultDate: "+0w",
changeMonth: true,
numberOfMonths: 1,
onClose: function( selectedDate ) {
$( "#to" ).datepicker( "option", "minDate", "today" );
$( "#to" ).datepicker( "option", "minDate", selectedDate );
$( "#to" ).datepicker( "option", "maxDate", selectedDate);
}
});
$( "#to" ).datepicker({
defaultDate: "today",
changeMonth: true,
numberOfMonths: 1,
onClose: function( selectedDate ) {
$( "#from" ).datepicker( "option", "minDate", "today" );
}
});
});
</script>
<div class="form-group">
<label class="sr-only" for="eventedit">Start date:</label>
<input type="text" id="from" name="from" >
</div>
<div class="form-group">
<label class="sr-only" for="eventedit">End date:</label>
<input type="text" id="to" name = "to">
</div>-->
<div class="form-group">
<label for="Event Name">Event Name:</label>
<input type="text" class="form-control" name="eventname" id="" aria-describedby="helpId" placeholder="" required>
<small id="emailHelpId" class="form-text text-muted">Enter location of venue</small>
</div>
<div class='input-group date' id='datetimepicker1'>
<label for="Event Name">Set Event Date:</label>
<input name="date" type='text' class="form-control" id="" aria-describedby="helpId" required/><br>
<small id="helpId" class="form-text text-muted">Enter date of event</small>
<span class="input-group-addon">
<span class="glyphicon glyphicon-calendar"></span>
</span><br>
</div>
<script>
$(function () {
$('#datetimepicker1').datetimepicker();
var minDate = $( "#datetimepicker1" ).datepicker( "option", "minDate" );
minDate.datepicker( "option", "minDate", "today" );
});
</script>
<h2>Choose Booking Capacity</h2>
<div class="form-check">
<input type="radio" class="form-check-input" name="capacity" id="" checked value="upto100">
<label class="form-check-label">
<br>
<i class="fa fa-1x" aria-hidden="true"><h3>Up to 100 people</h3></i>
</label>
</div>
<%
if(venues.getUpto300() != null){
%>
<div class="form-check">
<input type="radio" class="form-check-input" name="capacity" id="" value="upto300">
<label class="form-check-label">
<br>
<i class="fa fa-1x" aria-hidden="true"><h3>Up to 300 people</h3></i>
</label>
</div>
<%
}
%>
<%
if(venues.getUpto500() != null){
%>
<div class="form-check">
<input type="radio" class="form-check-input" name="capacity" id="" value="upto500">
<label class="form-check-label">
<br>
<i class="fa fa-1x" aria-hidden="true"><h3>Up to 500 people</h3></i>
</label>
</div>
<%
}
%>
<%
if(venues.getUpto1000() != null){
%>
<div class="form-check">
<input type="radio" class="form-check-input" name="capacity" id="" value="upto1000">
<label class="form-check-label">
<br>
<i class="fa fa-1x" aria-hidden="true"><h3>Up to 1000 people</h3></i>
</label>
</div>
<%
}
%>
<button class="btn-view">Book Venue</button>
</form>
</div>
</body>
</html>
我需要从这个页面的数据库中检索项目
<%--
Document : MyEvents
Created on : Jul 23, 2019, 11:17:46 AM
Author : Tariana
--%>
<%@page import="entities.Event"%>
<%@page import="java.util.Iterator"%>
<%@page import="java.util.List"%>
<%@page import="newpackage.Booking"%>
<%@page import="org.hibernate.Query"%>
<%@page import="org.hibernate.Session"%>
<%@page import="org.hibernate.service.ServiceRegistryBuilder"%>
<%@page import="entities.Users"%>
<%@page import="org.hibernate.cfg.Configuration"%>
<%@page import="org.hibernate.service.ServiceRegistry"%>
<%@page import="org.hibernate.SessionFactory"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<%
//checks whether there is a farmer account with a session within the system
//this header spans over all the pages after the farmer has logged into the system
if(session.getAttribute("mail") == null){
out.println("<script type=\"text/javascript\">");
out.println("alert('You need to login first!!');");
out.println("window.location.href = \"/Eventer/Users/Login.jsp\";");
out.println("</script>");
}else{
%>
<html>
<head>
<%@include file="BookHeader.jsp" %>
<title>My Events</title>
</head>
<body class="eventer">
<div class="kadi">
<%
SessionFactory sessionFactory;
ServiceRegistry serviceRegistry;
Configuration configuration = new Configuration();
configuration.addAnnotatedClass(Users.class)
.configure();
serviceRegistry = new ServiceRegistryBuilder()
.applySettings(configuration.getProperties())
.configure("hibernate.cfg.xml")
.build();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
Session sess = sessionFactory.openSession();
String hql = "FROM Booking";
Query queryy = sess.createQuery(hql);
List<Booking> buying;
List results = queryy.list();
buying = results;
Iterator<Booking> itr = buying.iterator();
Users owner;
Event venue;
Booking event = new Booking();
System.out.println();
while(itr.hasNext()){
Booking g = itr.next();
event = g;
%>
<div class="card">
<img class="card-img-top" src="event.png" alt="">
<div class="card-body">
<h4 class="card-title"><%=event.getEventname()%></h4>
<p class="card-text">Date: <%=event.getDate()%></p>
<p class="card-text">Capacity for: <%=event.getCapacity()%></p>
<p class="card-text eve">ksh.<%=event.getPricing()%></p>
<form>
<div class="form-group">
<label class="sr-only" for="inputName">Hidden input label</label>
<input type="text" class="form-control" name="inputName" id="inputName" placeholder="" value="" hidden>
<button type="submit" class="btn-view">View Venue</button>
</div>
</form>
</div>
</div>
<%
}
%>
</div>
</body>
</html>
<%
}
%>
预订舱位
package newpackage;
// Generated Jul 23, 2019 11:11:55 AM by Hibernate Tools 4.3.1
/**
* Booking generated by hbm2java
*/
public class Booking implements java.io.Serializable {
private Integer id;
private String capacity;
private String date;
private String eventname;
private String venue;
private String owner;
private int pricing;
private String user;
public Booking() {
}
public Booking(String capacity, String date, String eventname, String venue, String owner, int pricing, String user) {
this.capacity = capacity;
this.date = date;
this.eventname = eventname;
this.venue = venue;
this.owner = owner;
this.pricing = pricing;
this.user = user;
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getCapacity() {
return this.capacity;
}
public void setCapacity(String capacity) {
this.capacity = capacity;
}
public String getDate() {
return this.date;
}
public void setDate(String date) {
this.date = date;
}
public String getEventname() {
return this.eventname;
}
public void setEventname(String eventname) {
this.eventname = eventname;
}
public String getVenue() {
return this.venue;
}
public void setVenue(String venue) {
this.venue = venue;
}
public String getOwner() {
return this.owner;
}
public void setOwner(String owner) {
this.owner = owner;
}
public int getPricing() {
return this.pricing;
}
public void setPricing(int pricing) {
this.pricing = pricing;
}
public String getUser() {
return this.user;
}
public void setUser(String user) {
this.user = user;
}
}
我需要学习一种方法来比较对象或将对象更改回原来的对象状态
我想尝试一个将每个元素转换为字符串的 .tostring 方法，但它会引发一个问题，例如我存储类的问题，例如上述 POJO 类中的所有者，这将导致我目前面临的相同问题
【问题讨论】：
-
fromstring方法是什么？ -
请阅读“如何创建minimal reproducible example”。然后使用edit 链接改进您的问题（不要通过 cmets 添加更多信息）。否则我们无法回答您的问题并为您提供帮助。 “但它仍然不起作用”......不是一个有效的问题描述。您只发布了您的 Event 类，但 none 您的“测试”代码将实例化一个 Event、对其调用 toString() 或 fromstring() （无论首先实现该方法） .
-
除此之外：您实际上想要做什么？将对象转换为特定的字符串格式（如 JSON）？或者您想发明自己的字符串格式，并使用它来（取消）持久化您的 Event 对象？
-
所以我改为将所有映射文件转换为字符串，将类元素转换为字符串，以便持久性工作
标签： java string hibernate casting tostring