如何遍历List< T>并在JSF Facelets中渲染每个项目 [英] How iterate over List<T> and render each item in JSF Facelets

问题描述

我想知道如何在Facelet中显示如下所示的List<T>:

I am wondering how to display a List<T> as obtained below in a Facelet:

public List<T> searchByString(String string) {
    return getEntityManager().createNamedQuery("Userdetails.findByUsername").setParameter("username", "%" + string + "%").getResultList();
}

<h:dataTable>是合适的方法吗?

推荐答案

您将需要对其进行迭代. JSF 2提供了三个迭代组件.前提是User实体如下所示，

You're going need to iterate over it. JSF 2 offers three iteration components out the box. Provided that the User entity look like below,

@Entity
public class User {
    private @Id Long id;
    private String username;
    private String email;
    private LocalDate birthdate;
    // Add/generate getters+setters.
}

，并且将搜索结果分配为Bean的List<User> users属性，该属性可以作为#{bean}，

and that the search results are assigned as a List<User> users property of a bean which is available as #{bean},

@Named @RequestScoped
public class Bean {
    private List<User> users;
    // Add/generate postconstruct+getter.
}

以下是一些基于此的示例:

here are some examples based on it:

1. ，这是一个生成HTML <table>的UI组件.

1. <h:dataTable>, an UI component which generates a HTML <table>.

<h:dataTable value="#{bean.users}" var="user">
    <h:column>#{user.id}</h:column>
    <h:column>#{user.username}</h:column>
    <h:column><a href="mailto:#{user.email}">#{user.email}</a></h:column>
    <h:column>#{user.birthdate}</h:column>
</h:dataTable>

，它是一个不会生成HTML标记的UI组件(因此，您必须自己以所需的方式编写所有HTML，可以轻松将其更改为例如<ul><li>，<dl><dt><dd>或<div><span>等):

<ui:repeat>, an UI component which generates no HTML markup (so, you'd have to write all that HTML in the desired fashion yourself, which could easily be changed to e.g. <ul><li>, or <dl><dt><dd>, or <div><span>, etc):

<table>
    <ui:repeat value="#{bean.users}" var="user">
        <tr>
            <td>#{user.id}</td>
            <td>#{user.username}</td>
            <td><a href="mailto:#{user.email}">#{user.email}</a></td>
            <td>#{user.birthdate}</td>
        </td>
    </ui:repeat>
</table>

，它是在视图构建时而不是视图渲染时运行的标记处理程序(此处的背景说明:

<c:forEach>, a tag handler which runs during view build time instead of view render time (background explanation here: JSTL in JSF2 Facelets... makes sense?), it also doesn't produce any HTML markup:

<table>
    <c:forEach items="#{bean.users}" var="user">
        <tr>
            <td>#{user.id}</td>
            <td>#{user.username}</td>
            <td><a href="mailto:#{user.email}">#{user.email}</a></td>
            <td>#{user.birthdate}</td>
        </td>
    </c:forEach>
</table>

另请参见:

• Java EE 6教程-向页面添加组件-使用<h:dataTable>
• >如何以及何时从中加载模型h:dataTable的数据库

See also:

• Java EE 6 tutorial - Adding components to a page - using <h:dataTable>
• How and when should I load the model from database for h:dataTable

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