如何将Bean中的项目列表显示到JSF网页上? [英] How do I display a list of items from a Bean onto a JSF webpage?
问题描述
我是JSF的新手,在学习建立在线书店应用程序的过程中。
我有1个类和1个bean: Book.java
和 BookCatelogBean.java
。 Book类有3个属性: id
, title
和 author
与它的相应的getters和setters。 BookCatelogBean
包含 ArrayList< Book>
,其中用 Books
(在将来我会将其连接到数据库)。
我有两个网页: index.xhtml
和 book.xhtml
。我想在 index.xhtml
上显示每个格式化为REST链接的书名列表,以及它们的ID为 book.xhtml
,像这样:< h:link outcome =book?id =#{bookCatelogBean.id}value =#{bookCatelogBean.title}/>
我知道如何使用 BookCatelogBean
显示1 book
但我想显示所有的?我有一个想法从 BookCatelogBean
调用 getAllBooks()
返回每个书籍标题的方法,我将每个人返回index.xhtml作为JavaserverFace链接而不是字符串?
感谢
这是我的代码:
Book.java
包书店;
import java.io.Serializable;
public class Book implements Serializable {
private int id;
private String title;
private String author;
public Book(int id,String title,String author){
this.title = title;
this.id = id;
this.author = author;
}
public String getAuthor(){
return author;
}
public void setAuthor(String author){
this.author = author;
}
public int getId(){
return id;
}
public void setId(int id){
this.id = id;
}
public String getTitle(){
return title;
}
public void setTitle(String title){
this.title = title;
}
}
BookCatelogBean.java / p>
包书店;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
@ManagedBean
@SessionScoped
public class BookCatelogBean implements Serializable {
private int currentItem = 0;
private ArrayList< Book> books = new ArrayList< Book>(Arrays.asList(
new Book(1,Theory of Money and Credit,Ludwig von Mises),
new Book(2,Man,Economy and State,Murry Rothbard),
new Book(3,Real Time Relationships,Stefan Molyneux)));
public String getTitle(){
return books.get(currentItem).getTitle();
}
public int getId(){
return books.get(currentItem).getId();
}
public String getAuthor(){
return books.get(currentItem).getAuthor();
}
}
index.xhtml
<?xml version ='1.0'encoding ='UTF-8'?&
<!DOCTYPE html PUBLIC - // W3C // DTD XHTML 1.0 Transitional // ENhttp://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">
< html xmlns =http://www.w3.org/1999/xhtml
xmlns:h =http://java.sun.com/jsf/html>
< h:head>
< title> BookShop< / title>
< / h:head>
< h:body>
< h:link outcome =book?id =#{bookCatelogBean.id}value =#{bookCatelogBean.title}/>
< / h:body>
< / html>
JSF2提供了两个迭代组件: < ui:repeat>
和 < h:dataTable>
。前者对响应没有任何反应(所以你对最终的HTML输出有100%的控制权),而后者在响应中呈现一个HTML < table>
< h:column>
表示< td>
的列。两个组件可以包括 List< E>
作为值。
bean如下:
@ManagedBean
@RequestScoped
public class BookCatalog implements Serializable {
private List< Book>图书;
@PostConstruct
public void init(){
books = new ArrayList< Book>();
books.add(new Book(1,Theory of Money and Credit,Ludwig von Mises));
books.add(new Book(2,Man,Economy and State,Murry Rothbard));
books.add(new Book(3,Real Time Relationships,Stefan Molyneux));
}
公开列表< Book> getBooks(){
return books;
}
}
$ c>< ui:repeat> 以生成例如< ul>< li>
:
< ul>
< ui:repeat value =#{bookCatalog.books}var =book>
< li>
< h:link value =#{book.title}outcome =book>
< f:param name =idvalue =#{book.id}/>
< / h:link>
< / li>
< / ui:repeat>
< / ul>
属性基本上暴露当前迭代的项目在组件内的EL范围内的给定名称)
下面是如何使用
< h:dataTable>
代替:< h :dataTable value =#{bookCatalog.books}var =book>
< h:column>
< h:link value =#{book.title}outcome =book>
< f:param name =idvalue =#{book.id}/>
< / h:link>
< / h:column>
< / h:dataTable>
对于JSTL
< c:forEach>
,这也是可能的,但你应该记住JSTL标签有不同的生命周期比JSF组件。长故事: JSF中的JSTL Facelets ...有意义吗? p>
另请参阅:
- 如何选择正确的bean作用域?
- 什么时候应该从数据库加载h:dataTable
- 创建实体的主 - 详细页面,如何链接它们以及要选择哪个bean范围
I'm new to JSF and in the process of learning im building an online book store application.
I have 1 class and 1 bean: Book.java
and BookCatelogBean.java
. The Book class has 3 properties: id
, title
, and author
with it's corresponding getters and setters. The BookCatelogBean
contains an ArrayList<Book>
where I populate it with Books
(in future I will connect it to a database).
I have two pages: index.xhtml
and book.xhtml
. I want to display the list of book titles on index.xhtml
each formatted as a REST link and their ID to book.xhtml
, like so: <h:link outcome="book?id=#{bookCatelogBean.id}" value="#{bookCatelogBean.title}" />
I know how to use BookCatelogBean
to display 1 book
but I want to display all of them? I have an idea to call a method from BookCatelogBean
called getAllBooks()
that returns each of the books titles but how would I return each one of them to index.xhtml as a JavaserverFace link instead of a string?
Thanks
Here is my code:
Book.java
package bookshop;
import java.io.Serializable;
public class Book implements Serializable {
private int id;
private String title;
private String author;
public Book(int id, String title, String author){
this.title = title;
this.id = id;
this.author = author;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
}
BookCatelogBean.java
package bookshop;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
@ManagedBean
@SessionScoped
public class BookCatelogBean implements Serializable {
private int currentItem = 0;
private ArrayList<Book> books = new ArrayList<Book>(Arrays.asList(
new Book(1, "Theory of Money and Credit", "Ludwig von Mises"),
new Book(2, "Man, Economy and State", "Murry Rothbard"),
new Book(3, "Real Time Relationships", "Stefan Molyneux")));
public String getTitle(){
return books.get(currentItem).getTitle();
}
public int getId(){
return books.get(currentItem).getId();
}
public String getAuthor(){
return books.get(currentItem).getAuthor();
}
}
index.xhtml
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html">
<h:head>
<title>BookShop</title>
</h:head>
<h:body>
<h:link outcome="book?id=#{bookCatelogBean.id}" value="#{bookCatelogBean.title}" />
</h:body>
</html>
JSF2 offers two iterating components out the box: <ui:repeat>
and <h:dataTable>
. The former renders nothing to the response (so you have 100% control over the final HTML output), while the latter renders a HTML <table>
to the response and requires a <h:column>
to represent a column of <td>
s. Both components can take among others a List<E>
as value.
So, you can just have your managed bean like follows:
@ManagedBean
@RequestScoped
public class BookCatalog implements Serializable {
private List<Book> books;
@PostConstruct
public void init() {
books = new ArrayList<Book>();
books.add(new Book(1, "Theory of Money and Credit", "Ludwig von Mises"));
books.add(new Book(2, "Man, Economy and State", "Murry Rothbard"));
books.add(new Book(3, "Real Time Relationships", "Stefan Molyneux"));
}
public List<Book> getBooks() {
return books;
}
}
And you can use <ui:repeat>
to generate for example an <ul><li>
:
<ul>
<ui:repeat value="#{bookCatalog.books}" var="book">
<li>
<h:link value="#{book.title}" outcome="book">
<f:param name="id" value="#{book.id}" />
</h:link>
</li>
</ui:repeat>
</ul>
(note that the var
attribute basically exposes the currently iterated item by exactly the given name in the EL scope within the component)
And here's how to use a <h:dataTable>
instead:
<h:dataTable value="#{bookCatalog.books}" var="book">
<h:column>
<h:link value="#{book.title}" outcome="book">
<f:param name="id" value="#{book.id}" />
</h:link>
</h:column>
</h:dataTable>
As to the JSTL <c:forEach>
, that's also quite possible, but you should keep in mind that JSTL tags have a different lifecycle than JSF components. Long story short: JSTL in JSF2 Facelets... makes sense?
See also:
- How to choose the right bean scope?
- When should I load the collection from database for h:dataTable
- Creating master-detail pages for entities, how to link them and which bean scope to choose
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