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：和。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> 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： p>
另请参阅：
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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