如何迭代Map< String，Collection>在素数表中 [英] how to iterate Map<String,Collection> in datatable in primefaces

问题描述

将JSF 2.1与Primefaces配合使用

Using JSF 2.1 with primefaces

class FOO{
String name;
String value;
public void setName(String name){
this.name=name;
}
public String getName(){
return this.name;
}
public void setValue(String value){
this.value=value;
}
public String getValue(){
return this.value;
}

}

我有一个Map<String, List<FOO>>

标题名称应为地图的关键字.我需要创建多个列(即Map的大小)，并且每个列都应具有FOO列表以在行中显示FOO.Name.

Header name should be Key of the Map. I need to create multiple columns (i.e. size of Map) and each column should have the list of FOO to display FOO.Name in rows.

例如: 如果地图的大小是4

For Example : if size of map is 4

库姆----- Key1

Coulmns-----Key1

第一列的行-针对Key1的List<FOO>

ROWs of 1st column - List<FOO> against Key1

Coulmns ----- Key2

Coulmns-----Key2

第一列的行-针对Key2的List<FOO>

ROWs of 1st column - List<FOO> against Key2

Coulmns ----- Key3

Coulmns-----Key3

第一列的行-针对Key3的List<FOO>

ROWs of 1st column - List<FOO> against Key3

Coulmns ----- Key4

Coulmns-----Key4

第一列的行-针对Key4的List<FOO>

ROWs of 1st column - List<FOO> against Key4

有人可以告诉我使用什么组件在xhtml页面中显示这种类型的输出吗?我尝试使用动态数据表创建，但无法显示出来.

Can someone tell me what component to use for displaying this type of output in xhtml page ? I have tried using dynamic datatable creation but not able to show this.

推荐答案

您的数据结构错误.将其更改为正确的数据结构.最简单的方法是在表示rows属性的List<Map<String, Object>>中收集数据. Map代表以列名作为键的列.将这些列名称收集在一个单独的List<String>中，该List<String>表示columns属性.最后按<p:columns>所示:

You've there a wrong data structure. Change it to the right data structure. Easiest is to collect the data in a List<Map<String, Object>> which represents the rows property. The Map represents the columns, keyed by a column name. Collect those column names in a separate List<String> which represents the columns property. Finally show it as follows by <p:columns>:

<p:dataTable value="#{bean.rows}" var="row">
    <p:columns value="#{bean.columns}" var="column">
        #{row[column]}
    </p:columns>
</p:dataTable>

如果需要，这里是将奇怪的数据结构转换为正确的数据结构的方式(并假设每个List<FOO>具有相同的大小；整个数据结构的意义不那么明显):

Here's how you could convert the strange data structure to the right data structure, if necessary (and assuming that each List<FOO> is of the same size; the whole data structure makes otherwise less sense):

Map<String, List<FOO>> wrongDataStructure = createItSomehow();
List<String> columns = new ArrayList<String>(wrongDataStructure.keySet()); // Note I expect LinkedHashMap ordering here.
List<Map<String, Object>> rows = new ArrayList<Map<String, Object>>();
int size = wrongDataStructure.values().iterator().next().size();

for (int i = 0; i < size; i++) {
    Map<String, Object> row = new HashMap<String, Object>();

    for (String column : columns) {
        row.put(column, wrongDataStructure.get(column).get(i).getName());
    }

    rows.add(row);
}

// Now use "columns" and "rows".

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